PeakTech 4065 User manual

PeakT
ech
®
4065
Operation manual
DDS Arbitrary
Waveform enerator

1. Safety Precautions
This product complies with the requirements of the following European Community Directives: 2004/108/EG
(Electromagnetic Compatibility) and 2006/95/EG (Low Voltage) as amended by 2004/22/EC (CE-Marking).
Overvoltage category II; pollution degree 2.
To ensure safe operation of the equipment and eliminate the danger of serious injury due to short-circuits
(arcing), the following safety precautions must be observed.
Damages resulting from failure to observe these safety precautions are exempt from any legal claims
whatever.
* The instrument must be set up so that the power plug can be removed from the socket easily.
* Prior to connection of the equipment to the mains outlet, check that the available mains voltage
corresponds to the voltage setting of the equipment.
* Connect the mains plug of the equipment only to a mains outlet with earth connection.
* Do not place the equipment on damp or wet surfaces.
* Do not cover the ventilation slots of the cabinet to ensure that the air is able to circulate freely inside.
* Do not insert metal objects into the equipment by way of the ventilation slots.
* Do not place water filled containers on the equipment (danger of short-circuit in case of knock over of the
container).
* Do not exceed the maximum permissible input ratings (danger of serious injury and/or destruction of the
equipment).
* To avoid electric shock, disconnect power to the unit under test and discharge all capacitors before taking
any resistance measurements.
* Check test leads and probes for faulty insulation or bare wires before connection to the equipment.
* To avoid electric shock, do not operate this product in wet or damp conditions. Conduct measuring works
only in dry clothing and rubber shoes, i. e. on isolating mats.
* Comply with the warning labels and other info on the equipment.
* The measurement instrument is not to be to operated unattended.
* Do not subject the equipment to direct sunlight or extreme temperatures, humidity or dampness.
* Do not subject the equipment to shocks or strong vibrations.
* Do not operate the equipment near strong magnetic fields (motors, transformers etc.)
* Keep hot soldering irons or guns away from the equipment.
* Allow the equipment to stabilize at room temperature before taking up measurement (important for exact
measurements).
* Do not input values over the maximum range of each measurement to avoid damages of the meter.
* Use caution when working with voltages above 35V DC or 25V AC. These Voltages pose shock hazard.
* Periodically wipe the cabinet with a damp cloth and mid detergent. Do not use abrasives or solvents.
* The meter is suitable for indoor use only
* Do not operate the meter before the cabinet has been closed and screwed safely as terminal can carry
voltage.
* Do not store the meter in a place of explosive, inflammable substances.
* Do not modify the equipment in any way
* Do not place the equipment face-down on any table or work bench to prevent damaging the controls at
the front.
* Opening the equipment and service – and repair work must only be performed by qualified service
personnel
*-Measuring instruments don’t belong to children hands-
-1-

2. Introduction of PeakTech
®
4065 Function/Arbitrary Waveform Generator
With Direct Digital Synthesis (DDS) technology, the PeakTech
®
4065 Function/Arbitrary Waveform
Generator is of the high performance indexes and rich function characteristics which are necessary for the
fast completion of measuring. The clear and bright VFD fluorescent display interface is convenient for the
users to operate and observe.
The generator has the following advanced specifications and powerful function characteristics:
* Two-channel output: two independent output channels, CHA and CHB, the
characteristics of the two are the same
* Sync output: output sync signal
* Frequency characteristics: frequency accuracy 20 ppm, 6 digits, resolution 1µHz
* Amplitude offset characteristics: amplitude and offset accuracy 1％, 5 digits, resolution 0.1mV
* Unlimited measurement range: without limitation for the whole range, digital setting directly
* Non-intergraded process: up to the stable value immediately when switching, continuous
signal phase and amplitude without deflection
* High waveform accuracy: the output waveform is synthesized by the computation value of
functions with higher waveform accuracy and less distortion
* Square and Ramp: set accurate square duty cycle and Ramp symmetry
* Pulse: set accurate pulse width
* Arbitrary: 11 internal fixed waveforms and 5 user-defined waveforms
* Phase characteristics: set phase difference of CHA and CHB
* Modulation characteristics: output FM, AM, PM, PWM, FSK signal
* Frequency sweeping: be of the function of output linearity or logarithm frequency
sweeping signal, start point and stop point can be set arbitrarily
* Burst characteristics: output burst signal of which the number has been set.
* External trigger: external trigger is available under frequency sweeping, FSK
modulation and burst function.
* Frequency measurement: be of the function of frequency measurement function.
* Computation function: frequency or period, amplitude virtual value or peak-peak value
can be selected.
* Operation mode: keyboard operation, fluorescent display screen, direct digital
setting or continuous adjusting by knobs.
* High reliability: large scale integrated circuit, surface-mount technology, high
reliability and long service life
* Programmable interface: equipped with USB device interface, with which the generator
could be program-control and download waveforms
* Programmable interface: equipped with USB host interface, with which the parameter setting
and user-defined waveforms could be stored to a U disk
3. Chapter 1 Getting started
The front and rear panels, operations and functions of the PeakTech
®
4065 function generator are described
in this chapter so as to help users to master the basic operation as quickly as possible. The main contents of
this chapter are as follows:
3.1. Prepare the generator for use
3.1.1. Check the generator and the accessories
Check the completeness of the generator and its accessories based on the package list. If the packing box is
damaged badly, please keep it till the generator passes the performance test.
-2-

3.1.2. Connect to power supply
Boot the generator only under the following conditions.
Voltage: AC 100 ~ 240 V
Frequency: 45 ~ 65 Hz
Power consumption: < 30 V A
Temperature: 0 ~ 40°C
Humidity: < 80 %
Plug the attaching plug into an AC 100 ~ 240 V outlet with grounding conductor, press the mains switch on
the panel in to turn on the generator. The generator now is initializing itself and obtaining the default
parameters, outputting sine waveform under continuous working state, with frequency and amplitude of the
signal displayed.
Warning!
In order to ensure the security of the operator, use triple- core socket outlet with grounding conductor.
3.2. Front panel
1. Power switch
2. Function keys
3. CHA output
4. CHB output
5. SYNC output
6. Arrow keys
7. Display screen
8. Number keys
9. Adjusting knob
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1. 2. 3. 4. 5. 6.
7. 8. 9.

3.3. Rear panel
1. Modulation in
2. Trig in
3. Count in
4. Fan
5. Power socket
6. USB Device
7. USB Host
3.4 Display introduction
The display screen display two groups of digits, the group on the left with 6 digits shows frequency, period
and attenuation and so on of the signals. And the 5 digits on the right show amplitude, offset, duty cycle and
so on of the signals. There are also letter and letter indicator lights on the display screen, to indicate present
waveform signal, parameter options and also units of parameters.
3.5 Keyboard introduction
There are totally 28 keys on the front panel (see front panel picture), the functions of which respectively are:
【0】【1】【2】【3】【4】【5】
【6】【7】【8】【9】keys: Digits inputting key.
【.】key: Point inputting key.
【-】key: Minus inputting key, press this key to input minus under offset and
waveform edition option. Press this key to enable or disable the key-
tone circularly under other options.
【＜】key: Move the cursor left; delete the input when inputting digits.
【＞】key: Move the cursor right.
【Freq/Period】select frequency and period circularly; disable calibration process when
calibrating.
【Ampl/Offset】keys: select amplitude and offset circularly.
【Width/Duty】key: select pulse width, duty cycle of square or symmetry of Ramp circularly.
【FM】【AM】【PM】【PWM】
【FSK】【Sweep】【Burst】keys: press them to select respectively frequency modulation, amplitude
modulation, phase modulation, pulse width modulation, frequency shift
keying, frequency sweeping and burst functions, press again to return
back to continuous function.
-4-
1. 2. 3. 4. 5.
6. 7.

【Count/Edit】key: press this key to select waveform edition function when CHA output
user-defined waveforms, and select frequency measurement function
under other functions, press again to return back to continuous function.
【Menu】key: key for menu, select different options circularly under different
functions(see below function option list).
【Shift/Local】key: select shift, or press this key to resume keyboard function under
program control state.
【Output】key: open and close output signal circularly.
【Sine】【Square】【Ramp】
【Pulse】keys: shift keys, select respectively sinewave, square, Ramp and pulse four
common waveforms fast.
【Waveform】key: shift key, select respectively 16 kinds of waveforms with the waveform
sequence numbers.
【CHA/CHB】key: shift key, select CHA and CHB as output channel circularly.
【Trig】key: shift key, manual trigger under frequency sweeping and burst functions
【Cal】key: shift key, select parameter calibration function.
Unit key: The five keys with unit characters above them on the left bottom of the
instrument are not shift keys, but double-function keys, press these
keys directly to execute the functions marked on themselves; when
inputting digits with numeric keys, press these five keys to select the
unit of the inputting and end the digits inputting at the same time.
Options list of menu
Menu Option
CHA continuous Amplitude attenuation, output mode, state and waveform storage, state recall
CHB continuous Amplitude attenuation, output mode, AB phase difference, version number
FM Frequency deviation, modulation frequency, modulation waveform, modulation
source
AM Modulation amplitude depth, modulation frequency, modulation waveform,
modulation source
PM Phase deviation, modulation frequency, modulation waveform, modulation
source
PWM Pulse width deviation, modulation frequency, modulation waveform, modulation
source
FSK Hop frequency, hop rate, trigger source
Frequency sweeping Start frequency, end frequency, sweep time, sweep mode, trigger source
Burst Repeated period, pulse count, start phase, trigger source
Waveform edition Edition point number, horizontal phase, vertical voltage
Frequency measurement Gate time
Calibration Calibration value: zero, offset, amplitude, frequency, flatness
3.6. Basic operation
Below are some samples to describe the basic operation of the generator, for more complex usage and
problems, please refer to the details in chapter 3.
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3.6.1. CHA continuous function
* CHA continuous function: CHA outputs stable and continuous signal with continuous.
Press【Shift】【CHA/CHB】key, select “CHA” option, and set CHA parameters.
* Frequency setting: set frequency value as 3.5kHz
Press【Freq】key and select “Hz” unit, press【3】【.】【5】【kHz】.
* Frequency adjusting: Press【＜】or【＞】key to move the cursor, switch the adjusting knob left or right
to decrease or increase the digit on the cursor position, borrowing from or carrying to the former digit
continuously. Move the cursor left to do rough adjusting, and right to do fine adjusting. The adjusting knob
is applicable for adjusting digits of other options too, which will not be described any more.
* Period setting: set the period as 2.5ms
Press【Period】key and select “s” unit, press【2】【.】【5】【ms】.
* Amplitude setting: set amplitude value as 1.5Vpp
Press【Ampl】key and select “Vpp” unit, press【1】【.】【5】【Vpp】.
* Attenuation setting: set attenuation as 0dB
Press【Menu】key and select “Atten” option, press【0】【dB】.
* Offset setting: set DC offset as -1Vdc
Press【Offset】key and select “V DC” unit, press【-】【1】【V DC】.
* Common waveform selection: select square
Press【Shift】【Square】.
* Duty cycle setting: set square duty cycle as 20％
Press【Duty】key, press【2】【0】【％】.
* Other waveform selection: select exponent waveform sequence number 5, see waveform sequence
number table)
Press【Shift】【Waveform】key, press【5】【#】.
* Output mode selection: the phase of output signal is the opposite of the one of sync signal
Press【Menu】key, select “Mode” option and press 【1】【#】.
3.6.2. CHB continuous
* CHB continuous: CHB outputs stable and continuous signal with continuous.
Press【Shift】【CHA/CHB】key, select “CHB” option and set CHB parameters.
* AB phase difference setting: set the phase difference of CHA and CHB as 90°
Press【Menu】key, select “Phase” option and press【9】【0】【°】.
* Other parameter setting of CHB is the same as the one of CHA.
3.6.3. Frequency modulation function
* Frequency modulation function: set the CHA continuous as 20 kHz first.
Press【FM】key to output frequency modulation signal.
* Modulation frequency setting: set modulation frequency as 10Hz
Press【Menu】key, select “Mod_f” option and press【1】【0】【Hz】.
* Frequency deviation setting: set frequency deviation as 2kHz
Press【Menu】key, select “Devia” option and press 【2】【kHz】.
* Modulation waveform setting: set the modulation waveform as Ramp
Press【Menu】key, select “Shape” option and press【2】【#】.
* Modulation source setting: set external modulation source
Press【Menu】key, select “Source” option and press【1】【#】.
* Return back to continuous function: Under frequency modulation, press 【FM】key to return back to
continuous function.
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3.6.4. Amplitude modulation function
* Press【AM】key to output amplitude modulation signal.
* Modulation frequency setting: set modulation frequency as 1 kHz
* Press【Menu】key, select “Mod_f” option and press【1】【kHz】.
* Modulation amplitude depth setting: set modulation amplitude depth as 50％
* Press【Menu】key, select “Depth” option and press【5】【0】【％】.
* Modulation waveform setting: set modulation waveform as sinewave
* Press【Menu】key, select “Shape” option and press【0】【#】.
* Modulation source setting: set internal modulation source
* Press【Menu】key, select “Source” option and press【0】【#】.
* Return back to continuous function: Under amplitude modulation, press【AM】key to return back to
continuous function.
3.6.5. Phase modulation function
* Phase modulation function: Press【PM】key to output phase modulation signal.
* Modulation frequency setting: set modulation frequency as 10 kHz
Press【Menu】key, select “Mod_f” option and press【1】【0】【kHz】.
* Phase deviation setting: set phase deviation as 180°
Press【Menu】key, select “Devia” option and press【1】【8】【0】【°】.
* Modulation waveform setting: set modulation waveform as square
Press【Menu】key, select “Shape” option and press【1】【#】.
* Modulation source setting: set external modulation source
Press【Menu】key, select “Source” option and press【1】【#】.
* Return back to continuous function: Under phase modulation, press 【PM 】key to return back to
continuous function.
3.6.6. Pulse width modulation function
* width modulation function: Press【PWM】key to output pulse width modulation signal.
* Modulation frequency setting: set modulation frequency as 1Hz
Press【Menu】key, select “Mod_f” option and press【1】【Hz】.
* Pulse width deviation setting: set pulse width deviation as 80 %
Press【Menu】key, select “Devia” option and press【8】【0】【%】.
* Modulation waveform setting: set modulation waveform as sinewave
Press【Menu】key, select “Shape” option and press【0】【#】.
* Modulation source setting: set internal modulation source
Press【Menu】key, select “Source” option and press【0】【#】.
* Return back to continuous function: Under pulse width modulation, press【PWM】key to return back to
continuous function.
3.6.7. Frequency shift keying function
* Frequency shift keying function: set waveform as sinewave
Press【FSK】key to output frequency shift keying signal.
* Hop rate setting: set hop rate as 1 kHz
Press【Menu】key, select “Rate” option and press【1】【kHz】.
* Hop frequency setting: set hop frequency as 2 kHz
Press【Menu】key, select “Hop_f” option and press【2】【kHz】.
* Trigger source setting: set internal trigger source
Press【Menu】key, select “Source” option and press【0】【#】.
* Return back to continuous function: Under frequency shift keying function, press【FSK】key to return
back to continuous function.
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3.6.8. Frequency sweeping function
* Frequency sweeping function: Press【Sweep】key to output frequency sweeping signal.
* Start frequency setting: set the start frequency as 5 kHz
Press【Menu】key, select “Start” frequency and press【5】【kHz】.
* End frequency setting: set end frequency as 20 Hz
Press【Menu】key, select “Stop” and press【2】【0】【Hz】.
* Sweeping time setting: set sweeping time as 5 s
Press【Menu】key, select “Time” option and press【5】【s】.
* Sweeping mode setting: set logarithm sweeping mode
Press【Menu】key, select “Mode” option and press【1】【#】.
* Trigger source setting: set external trigger source
Press【Menu】key, select “Source” option and press【1】【#】.
* Single trigger setting: trigger sweeping once
Press【Shift】【Trig】keys to trigger sweeping once.
* Return back to continuous function: Under frequency sweeping, press【Sweep】key to return back to
continuous function.
3.6.9. Burst function
* Burst function: set continuous as 1 kHz
Press【Burst】key to output burst signal.
* Repeated period setting: set repeated period as 5ms
Press【Menu】key, select “Period” option and press【5】【ms】.
* Pulse count setting: set pulse count as 1
Press【Menu】key, select “Ncyc” option and press【1】【#】.
* Start phase setting: set start phase as 180°
Press【Menu】key, select “Phase” option and press【1】【8】【0】【°】.
* Trigger source setting: set internal trigger source
Press【Menu】key, select “Source” option and press【0】【#】.
* Return back to continuous function: Under burst function, press【Burst】to return back to continuous
function.
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4. Chapter 2 Principle introduction
This chapter describes the basic concept of signal shaping and internal operation of the generator, to help
users to learn more about the performance and specifications then operate the generator more smoothly.
4.1. Principle diagram of generator
4.2. DDS working principle
To generate a voltage signal, traditional analog function generator adopt electronic components to consist
oscillator by many different means, the signals generated are of poor frequency accuracy and stability, low
resolution, inconvenient to set frequency and programmed with computer, but request complex techniques.
Direct Digital Synthesis (DDS) technology is an up-to-date technique to generates signals, it need no
oscillator but digital synthesis technique to generate series of data-current which convert to analog signals
through digital-analog converter.
To generate a sine signal, for example, the function of Y＝SinX should be digitally quantized first, and then
taking x as the address and y as the quantized data to store them into waveform memorizer. DDS uses
phase adding technique to control the address of waveform memorizer. Add a phase increment on the
present result of phase accumulator in each sampling clock period so as to change the output frequency
value by change phase increment. According to the address from the phase accumulator, take the quantized
data out from the wave memorizer and then convert it into analog voltage via digit-analog converter and
operation amplifier. Since the waveform data are discontinuous sampling, stair sine waveform is output from
DDS generator. The included high-level harmonic wave should be filtered by lowpass filter so to output a
continuous sine wave. With high accurate reference voltage source in digit-analog converter, the output
waveform is of high amplitude accuracy and stability.
-9-
Micro-
controller
MCU
Digital
synthesis
FPGA
Digital-analog
converter D/A
Amplitude
control
Offset
control
Clock 20 MHz
Keyboard,
display,
adjusting knob
Voltage
amplification
Power
amplification
Attenuator
20dB+40dB
SYNC output
Output port
Output
protection
Lowpass filter
Data storage
FLASH
Programmable
interface
USB
Power

Amplitude controller is a multiplication digital-analog converter, analog signal that has been filtered is the
voltage standard of the digital-analog converter, this standard multiplies amplitude value inputting with the
numeric key to make output signal frequency be equal to this inputting value. Offset controller is also a
multiplication digital-analog converter, a high-accuracy DC voltage standard of which multiplies offset value
inputting with the numeric key to make the output signal offset be equal to this inputting value. The
synthesized signal from amplitude and offset controllers is amplified by the power amplifier and voltage
amplifier then output from output port.
4.3. Control working principle
Micro-controller controls the keyboard and display parts with interface circuit, when a key is pressed, the
micro-controller recognizes the code of pressed key and executes corresponding command program of this
key. The display circuit will work to display the instrument’s working state and each parameter.
Switch the adjusting knob on the panel to change the digit on the cursor position, generating a trigger pulse
every 15° rotation. The microprocessor could judge the rotation is left or right, if it is left, the number in the
position of cursor will be subtracted by 1; if it is right, the number in the position of cursor will be added by 1
with continuous carry or borrow.
5. Chapter 3 Reference
5.1. Data input
5.1.1. Input with the numeric keys
Select an option and input with the numeric keys the parameters of this option. The ten digit keys are of the
function of inputting data from left to right one by one. Point is allowed in this data, but only the first one is
valid when more than one points inputted. Under “offset” function, minus may be input. The digit keys input
digit to the display area which do not work yet and could be deleted by pressing 【＜】, or select this option
again, to input right one if it is a wrong input, but these must happen before pressing an unit key. End the
digits input and make them valid by pressing an unit key.
For any input by pressing the point key and the units, the generator will display this input in its own certain
form. Such as, the generator displays 1.50000 kHz for both of input of 1.5 kHz and 1500 Hz.
5.1.2. Adjust with the adjusting knob
In actual operations, users may use the adjusting knob to continuously adjust the signal. Press 【＜】or
【＞】to move the cursor left or right. Rotate the adjusting knob on the front panel right to add the digit on
the cursor position by 1, it can do a carry to the former; rotate the adjusting knob left to subtract the digit on
the cursor position by 1, it can borrow digit from the former. The digit adjusted by the adjusting knob works
immediately and no need to press unit key. Move the cursor to the left to do rough adjusting by the knob, and
to the right to do fine adjusting.
5.1.3 Selection of the inputting means
For known data, it is the most convenient to use numeric keys to input as it can be gotten easily without the
generating of transient data no matter how big the change of the data is, which is so important in some
operations. For the modifying of the entered data or for entering sequence data to observe, it will be more
convenient to use the adjusting knob. So user should select flexibly according to the different applications.
5.2. CHA continuous
“CHA continuous” means CHA outputs stable and continuous signal, of which the waveform, frequency,
amplitude and phase will not change along with time.
Press【Shift】【CHA/CHB】key, select “CHA” option and then set the parameters of CHA.
5.2.1. Frequency setting
Press【Freq】key, the light of which will be on, press “Hz” unit to display present frequency value. Input
frequency value with numeric keys or adjusting knob and the signals of this frequency will be output from the
output port.
-10-

5.2.2. Period setting
Press【Period】key, the light of which will be on, press “s” unit to display present period value, input period
value with numeric keys or adjusting knob. Frequency is synthesized in the internal of the generator, and
converted to period when inputting and displaying. Limited by the frequency low resolution, for a
comparatively long period, the generator could only output some frequency points with long period interval,
so the period of actual output signal may be comparatively different from them, which should be under
consideration during operations.
5.2.3 Amplitude setting
Press【Ampl】key, the light of which will be on, press “Vpp” or “Vrms” to display present amplitude value,
input amplitude value with numeric keys or adjusting knob and the signals of this amplitude will be output
from the output port.
The relation between maximum amplitude and DC offset value should be below formula, if the setting of
amplitude exceeds specification, the generator will modify it until it is within the range of allowed maximum
amplitude value.
Vpp ≤2 × (10-|offset|)
5.2.4 Amplitude value form
There are two forms for amplitude input and display: peak-peak form and RMS form. Press 【Vpp】or
【mVpp】to input amplitude peak-peak value after inputting the digits, press【Vrms】or【mVrms】to input
amplitude RMS value. RMS value is applicable only to sinewave, square wave, Ramp wave and pulse wave
four common waveforms, and other waveforms could only be shown by amplitude peak-peak value.
5.2.5. Amplitude attenuation setting
Press【Ampl】key and select “Atten” option to show the present attenuation value. Amplitude attenuation is
auto as default of booting and there display “Auto”, the generator will select automatically proper attenuation
proportion according to the amplitude setting value, higher amplitude resolution, higher signal-noise ratio and
less waveform distortion could be realized at the same time regardless of the amplitude magnitude of the
signal. The output signal makes a momentary hop when the attenuation changes, which is not welcome in
some operations, but the generator has fixed attenuation function to avoid this circumstance. Input
attenuation values of 0dB, 20dB, 40dB and 60dB with the numeric keys, input 80dB to select auto
attenuation. Users may use the adjusting knob as well, the attenuation changes to next one for every step of
the rotation. When select fixed attenuation mode, the attenuation is fixed while the signal amplitude changes,
and the output signal could changes continuously within the whole amplitude range. But higher distortion of
the waveform and poor signal-noise ratio maybe appear when the attenuation is 0dB and the amplitude of
the signal is small.
5.2.6. Output load
The setting value of amplitude is calibrated when the output end is open. The real voltage of output load is
the setting value of amplitude multiplied by the assignment ratio of load impedance and output impedance.
The output impedance of the generator is fixed at 50Ω. When the load impedance is high enough, the
assignment ratio approaches to 1. The voltage loss of output impedance can be neglected. The real voltage
approaches to the setting value of amplitude. But when the load impedance is lower, the voltage loss of
output impedance cannot be neglected. It should be paid more attention that the real voltage does not
accord with the setting value of amplitude. Especially when the frequency is comparatively high, the output
and the change of inductance and condensance on the load will cause a comparatively large error.
With 50Ωoutput resistance, a momentary short-circuit of the output port makes no damage to the generator,
but the users should try to avoid long time short-circuit under high voltage output as a danger of making
damage to the generator. The generator has function of opposite voltage protection, with which the generator
close output automatically, make an alarm with the output indicating light off when carelessly connect a high
voltage(less than 30V) to the output port. Open the output by pressing 【Output】key only after the fault
cleared.
-11-

5.2.7. Offset setting
Press【Offset】key, the light of which will be on, press “V DC” unit to display present offset value. Input
offset value with the numeric keys or adjusting knob for the output signal to generate this DC offset.
The relationship between the maximum DC offset and amplitude value should be below formula, if the setting
of offset exceeds, the generator will modify it until it is within the limit of the maximum offset value.
|offset|≤10-Vpp÷2
When it comes to adjust the DC offset of the output signals, it is more convenient to use the adjusting knob
than the numeric keys. As usual, taking no account of the sign of the present DC offset, right rotation makes
the DC level up, while left rotation makes it down, the sign of the DC offset value changes automatically
when passing the zero point.
5.2.8. DC voltage output
Set amplitude at 0V, the offset value could be set arbitrarily within ±10 V range, the generator is now a DC
voltage power supply and outputs specified DC voltage signal.
5.2.9. Output waveform selection
The generator could output 16 kinds of waveforms, and sine, square, Ramp and pulse are four common
waveforms, press 【Shift】【Sine】【Shift】【Square】【Shift】【Ramp】and 【Shift】【Pulse】keys to
select them directly, the corresponding waveform character light will be on. All 16 kinds of waveforms could
be selected with the waveform sequence numbers, press【Shift】【Waveform】key, and the instrument
shows the present waveform sequence number, users may select output waveforms by inputting waveform
sequence number with the numeric keys or adjusting knob. Except the four common waveforms, the
waveform character of other waveforms is “Arb”. The waveform sequence numbers of 16 kinds of waveforms
are as listed as below:
Waveform sequence numbers list
Sequence
number
Waveform Sequence
number
Waveform Sequence
number
Waveform
00 Sine 06 Logarithm 12 User-defined 2
01 Square 07 Sinc 13 User-defined 3
02 Ramp 08 Half-round 14 User-defined 4
03 Pulse 09 Cardiogram 15 User-defined 5
04 White noise 10 Vibration
05 Exponent 11 User-defined 1
5.2.10. Duty cycle setting
When the present selection of waveform is square, press【Duty】key, the “Duty” keyboard light will be on
and the generator display current duty cycle value, input duty cycle value with numeric keys or adjusting
knob, then the output will be a square with a fixed duty cycle value. While the frequency of square changes,
its duty cycle keeps the same. The definition of square duty cycle is the ratio of high level time of one square
to the period of this square. When the frequency of square is comparatively high, the setting of duty cycle is
limited by the edge time, in a relationship as below formula:
Duty cycle× Period≥2× Edge time or Duty cycle ×Period≤Period－(2× Edge time)
5.2.11. Symmetry setting
When the present selection of waveform is Ramp, press【Duty】key, the “Duty” keyboard light will be on
and the generator display current symmetry value, input symmetry value with numeric keys or adjusting knob,
then the output will be a Ramp with a fixed symmetry value. While the frequency of a Ramp changes, its
symmetry keeps the same. The definition of Ramp symmetry is the ratio of rising time of one Ramp to the
period of this Ramp. Ramp with 100% symmetry is named as rising Ramp wave, and Ramp with 0%
symmetry is named as falling Ramp wave, Ramp with 50% symmetry is named as triangle wave.
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5.2.12. Pulse width setting
Select pulse wave and press【Width】key, the “Width” keyboard indicator will be lighted and the generator
display current pulse width value, the users may use the numeric keys or knob to input pulse width value,
and the generator will output pulse wave with this pulse width set. The pulse width keeps unchanging while
the pulse frequency changes. Pulse width is defined as, the time value of the high level of the pulse wave.
When the frequency of the pulse wave is comparatively high, the set of pulse width will be limited by edge
time, and should accord with below formula:
Pulse width≥2×edge time or period-pulse width≥2×edge time
5.2.13. Output mode setting
Press【Menu】key and select “Mode” option to display the output mode value, use the numeric keys or knob
to input mode value. There are only two values to choose: 0 or 1, when set the value as 0, the signal from
the output port is in-phase with the sync port, and when set it as 1, the two are inverted.
5.3. CHB continuous
“CHB continuous” means CHB outputs stable and continuous signal, of which the waveform, frequency,
amplitude and phase will not change along with time.
Press【Shift】【CHA/CHB】key, select “CHB” option and then set parameters of CHB.
5.3.1. Phase difference between CHA and CHB setting
When the frequencies of CHA and CHB are the same, press【Menu】key and select “Phase” option, the
generator will indicate the phase difference between CHA and CHB, use the numeric keys or knob to input
phase difference value, the phase difference between signals from CHA and CHB could be set in advance. It
is meaningless to set phase difference when the frequencies of CHA and CHB are different.
The settings of other parameters of CHB is the same as the one of CHA.
Below contents give detail explanations of FM, AM, PM, PWM, FSK, frequency sweeping, burst and arbitrary
waveform functions, which are only applicable to CHA.
5.4. Frequency modulation (FM)
In Frequency modulation, the frequency of the carrier is varied by the instantaneous voltage of modulating
waveform, all the 16 kinds of waveforms listed in the waveforms table could be used as carrier waveform.
Before entering into frequency modulation, the users should set the waveform, frequency and amplitude
value of the carrier wave first under CHA continuous function.
Press【FM】key, the keyboard indicator of “FM” will be on, and CHA output frequency modulation signal.
5.4.1. Frequency deviation
Press【Menu】key and select “Devia” option, and then set frequency deviation value. Frequency deviation
represents the frequency variation of carrier wave when the modulating waveform is with full amplitude
during FM process. When the amplitude of the modulating waveform is at positive peak value, the output
frequency is equal to the frequency of the carrier plus the frequency deviation, and when it is at the negative
peak value, the output frequency is equal to the carrier frequency minus the frequency deviation. Therefore,
the frequency deviation setting must conform to the following two conditions:
(Carrier frequency－frequency deviation)＞0
(Carrier frequency＋frequency deviation)＜The upper limit of the generator
5.4.2. Modulation frequency
Press【Menu】key and select “Mod_f” option, and then set modulation frequency value. In FM, modulation
frequency is usually far lower than carrier frequency.
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5.4.3. Modulation waveform
Press【Menu】key and select “Shape” option, set modulation waveform by setting waveform No., the
modulation waveform may be any one of the 16 kinds of waveforms listed in the waveforms table.
5.4.4. Modulation source
Press【Menu】key, select “Source” option and then set modulation source, there are only two values to
choose: 0 and 1. Set the value as 0 to choose internal modulation source, and set it as 1 to choose external
modulation source. If external modulation source is chosen, connect a modulation signal to the 《Modulation
In》port on the rear panel of the generator. When external modulation signal reaching to full amplitude as
±5 V, the display of frequency deviation accords with its real value. Or the display of frequency deviation is
incorrect.
5.4.5. Sync output
In FM, the generator outputs a sync signal from the front panel “Sync” connector, which is a square wave
with TTL level and 50% duty cycle, its frequency is equal to modulating wave frequency and its phase is
referenced to the phase of the modulating wave.
In FM, press 【FM 】key, the keyboard indicator of “FM” will be off, the generator will exit frequency
modulation function and return back to continuous function.
5.5. Amplitude modulation (AM)
In AM, the amplitude of the carrier is varied by the instantaneous voltage of the modulating waveform, all the
16 kinds of waveforms listed in the waveforms table could be used as carrier waveform. Before entering into
amplitude modulation, the users should set the waveform, frequency and amplitude value of the carrier wave
first under CHA continuous function.
Press【AM】key, the keyboard indicator of “AM” will be on and CHA output amplitude modulation signal.
5.5.1. Modulation depth
Press【Menu】key and select “Depth” option, and then set modulation depth value. Modulation depth
represents the percentage of variation of the carrier amplitude to the amplitude setting value while the
modulating wave is with full amplitude during AM process. If the maximum amplitude of the modulated carrier
waveform is called as Amax, the minimum amplitude as Amin, the amplitude setting value as A, the
modulation depth as M, then the relationship between the four values is:
Amax＝(1+M)×A÷2.2 Amin＝(1-M)×A÷2.2
Then the modulation depth is M＝(Amax－Amin)×1.1÷A
If modulation depth is 120%, Amax=A, Amin=-0.09A. If modulation depth is 100%, Amax=0.909A, Amin=0. If
modulation depth is 50%, Amax=0.682A, Amin=0.227A. If modulation depth is 0 ％, Amax=0.455A,
Amin=0.455A. That is to say, when modulation depth is 0, carrier amplitude is about half of the amplitude
setting.
3.5.2. Modulation frequency
Press【Menu】key and select “Mod_f” option, and then set modulation frequency value. In AM, modulation
frequency is usually far lower than carrier frequency.
3.5.3. Modulation waveform
Press【Menu】key and select “Shape” option, set modulation waveform by setting waveform no. The
modulation waveform may be any one of the 16 kinds of waveforms listed in the waveforms table.
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5.5.4. Modulation source
Press【Menu】key, select “Source” option and then set modulation source, there are only two values to
choose: 0 and 1. Set the value as 0 to choose internal modulation source, and set it as 1 to choose external
modulation source. If external modulation source is chosen, connect a modulation signal to the 《Modulation
In》port on the rear panel of the generator. When external modulation signal reaching to full amplitude as
±5V, the display of modulation depth accords with its real value. Or the display of modulation depth is
incorrect.
5.5.5. Sync output
In AM, the generator outputs a sync signal from the front panel “Sync” connector, which is a square wave
with TTL level and 50% duty cycle, its frequency is equal to modulating frequency and its phase is
referenced to the phase of the modulating signal.
In AM, press【AM】key again, the “AM” indicator will be off, and the generator exits AM function and returns
back to continuous function.
5.6. Phase modulation (PM)
In PM, the phase of the carrier is varied by the instantaneous voltage of the modulating waveform, all the 16
kinds of waveforms listed in the waveforms table could be used as carrier waveform. Before entering into
phase modulation, the users should set the waveform, frequency and amplitude value of the carrier wave
first under CHA continuous function.
Press【PM】key to light “PM”, and the CHA output phase modulation signal.
5.6.1. Phase deviation
Press 【Menu 】key and select “Devia” option, and then set phase deviation value. Phase deviation
represents the variation of carrier phase while the modulating waveform is with full amplitude in phase
modulation. When the amplitude of the modulating waveform is at positive peak value, the phase of the
outputted signal increase one phase shift, and when it is at the negative peak value, the phase of the
outputted signal decrease one phase shift.
5.6.2. Modulation frequency
Press【Menu】key and select “Mod_f” option and then set modulation frequency value. In PM, modulation
frequency is usually far lower than carrier frequency.
5.6.3. Modulation waveform
Press【Menu】key and select “Shape” option, set modulation waveform by setting waveform No., the
modulation waveform may be any one of the 16 kinds of waveforms listed in the waveforms table.
5.6.4. Modulation source
Press【Menu】key, select “Source” option and then set modulation source, there are only two values to
choose: 0 and 1. Set the value as 0 to choose internal modulation source, and set it as 1 to choose external
modulation source. If external modulation source is chosen, connect a modulation signal to the 《Modulation
In》port on the rear panel of the generator. When external modulation signal reaching to full amplitude as
±5 V, the display of phase deviation accords with its real value. Or the display of phase deviation is incorrect.
3.6.5 Sync output: in PM, the generator outputs a sync signal from the front panel “Sync” connector, which is
a square wave with TTL level and 50% duty cycle, its frequency is equal to modulating frequency and its
phase is referenced to the phase of the modulating signal.
In PM, press【PM】key, the “PM” indicator will be off, the generator exits PM function and returns back to
continuous function.
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5.7. Pulse width modulation (PWM)
In PWM, the pulse width of the carrier varies with the instantaneous voltage of the modulating signal, and the
waveform shape of the carrier must be pulse. Before entering into PWM, users should firstly set the
frequency and amplitude of carrier wave under CHA continuous function.
Press【PWM】key, the keyboard indicator of “PWM” will be on and the CHA output phase width
modulation signal, the carrier wave is automatically set as pulse wave.
5.7.1. Pulse width deviation
Press【Menu】key and select “Devia” option, then set pulse width deviation value. It represents the
variation of carrier pulse width to the period of the pulse when the modulating waveform is with full amplitude
during PWM process, also the variation of the duty cycle. Name the maximum duty cycle of modulated
carrier as Dmax, and the minimum as Dmin, the pulse width deviation’s formula should be:
Pulse width deviation＝Dmax－Dmin
If Dmax=80%, Dmin=20%, the pulse width deviation is 60％. If Dmax=50%, Dmin=50%, the pulse
width deviation should be 0%. That is to say, when pulse width deviation is 0, the duty cycle of pulse wave is
50%.
5.7.2. Modulation frequency
Press【Menu】key, select “Mod_f” option and set modulation frequency value.
5.7.3. Modulation waveform
Press【Menu】key and select “Shape” option, set modulation waveform by setting waveform No.,
the modulation waveform may be any one of the 16 kinds of waveforms listed in the waveforms
table.
5.7.4. Modulation source
Press【Menu】key, select “Source” option and then set modulation source, there are only two
values to choose: 0 and 1. Set the value as 0 to choose internal modulation source, and set it as
1 to choose external modulation source. If external modulation source is chosen, connect a
modulation signal to the 《Modulation In》port on the rear panel of the generator. When external
modulation signal reaching to full amplitude as ±5V, the display of pulse width deviation accords
with its real value. Or the display of pulse width deviation is incorrect.
5.7.5. Sync output
In PWM, the generator outputs a sync signal from the front panel “Sync” connector, which is a square wave
with TTL level and 50% duty cycle, its frequency is equal to modulating frequency and its phase is
referenced to the phase of the modulating signal.
In PWM, press【PW M】key, the “PWM” keyboard indicator will be off, and the generator exits
PWM function and returns back to continuous function.
5.8. Frequency shift keying (FSK)
In FSK, the frequency of the carrier shifts between “carrier frequency” and “hop frequency”
alternately, the rate at which the output shifts is determined by hop rate, all the 16 waveforms
listed in the waveforms table could be used as carrier wave. Before entering into FSK, users
should firstly set the waveform, frequency and amplitude value of the carrier wave under CHA
continuous function.
Press【FSK】key to light “FSK” keyboard indicator, and CHA will output FSK signal.
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5.8.1. Hop frequency
Press【Menu】key to light “Hop_f” character, and then set hop frequency value. Frequency shift
keying is similar with FM whose modulating waveform is square. “hop frequency” is similar with
“frequency deviation”, with the difference of, frequency deviation is an offset value that the
frequency of carrier wave plus or minus, whose setting range is relational with the frequency of
carrier wave, hop frequency could be set arbitrarily within whole frequency range, it has no
relationship with carrier frequency.
5.8.2. Hop rate
Press 【Menu 】key to light “Rate” character, then set hop rate value. In FSK, the modulation
waveform is fixed as a square wave with 50% duty cycle, the frequency of the square wave is the
hop rate.
5.8.3. Trigger source
Press【Menu】key, select “Source” option and then set trigger source, there are only two values
to choose: 0 and 1. Set the value as 0 to choose internal trigger source, and set it as 1 to choose
external trigger source. If external trigger source is chosen, connect a TTL trigger signal to the
《Trig In》port on the rear panel of the generator. When the trigger signal is with logic low level,
the frequency of output signal is the carrier frequency. When the trigger signal is with logic high
level, the frequency of output signal is the hop frequency. When external trigger source is chosen,
the hop rate setting is ignored.
5.8.4. Sync output
In FSK, the generator outputs a sync signal from the front panel “Sync” connector, which is a
square wave with TTL level and 50% duty cycle, its frequency is equal to the hop rate. When the
output signal is the carrier, a low level sync signal is outputted. When the output is hop frequency,
a high level sync signal is outputted.
In FSK, press【FSK】key again, the “FSK” keyboard indicator will be off, the generator exits FSK
function and returns back to continuous function.
5.9. Frequency sweeping function
In frequency sweep, the output frequency changes from the start frequency point to the end
frequency point according to the setting sweep time. Users may sweep within the whole frequency
range. During this process, the phase of output signals is continuous. All the 16 kinds of
waveform except of pulse and white noise listed in the waveform table could be swept.
Linearity frequency sweeping is similar with Ramp frequency modulation, with the difference of,
frequency sweeping does not use modulation waveform, but continuously output a series of
discrete frequency points according to certain time interval.
Press【Sweep】key, the light of it will be lighted and the CHA output frequency sweeping signal.
5.9.1. Start and end frequency
Press【Menu】key to light “Start” letter and then set start frequency point. Press【Menu】key to
light “Stop” letter and then set end frequency point. If the end frequency value is more than the
start frequency value, the sweep is positive from lower frequency to higher frequency, increasing
step by step from the start frequency to the end frequency and then return to the start frequency.
If end frequency value is less than the start frequency value, the sweep is opposite from higher
frequency to lower frequency, decreasing step by step from the start frequency to the end
frequency and then return to the start frequency.
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5.9.2. Sweeping time
Press【Menu】key and select “Time” option and then set sweep time value. Sweep time means
the time of sweeping from the start frequency point to the end frequency point. The sweep time of
every frequency point is the same, so the longer the sweep time is, the more frequency points are
swept, the less the step of the frequency point is, and the finer the sweep is. The shorter of the
sweep time is, the less frequency points are swept, the more the step of the frequency point is,
and the rougher the sweep is.
5.9.3. Sweeping mode
Press【Menu】key and select “Mode” option to set sweeping mode. There are only two value of
sweeping mode: 0 and 1, Set the value as 0 to select “linear” option, and the sweeping mode now
is linearity. Set the value as 1 to select “log” option, to select logarithm mode.
Under linearity sweeping mode, the frequency step is fixed, but a fixed frequency step always
does a bad effect when sweeping comparatively wide-range frequency. In that case, the
resolution is high when sweeping high end of frequency, the frequency changes slowly, and the
sweeping is fine. But the resolution is low when sweeping the low end of frequency, the frequency
changes very quickly, the sweeping is rough. So linearity sweeping is applicable only for
sweeping with narrow frequency range.
Under logarithm sweeping mode, the frequency step value is not fixed but changes according to
logarithm relation. When sweeping the high end of frequency, the frequency step value is
comparatively large; when sweeping the low end of frequency, the frequency step value is
comparatively small. The frequency change is comparatively average for sweeping with wide
frequency range. So logarithm sweeping is applicable for sweeping with wide frequency range.
5.9.4. Trigger source
Press【Menu】key, select “Source” option and then set trigger source, there are only two values
to choose: 0 and 1. Set the value as 0 to choose internal trigger source, and set it as 1 to choose
external trigger source. If external trigger source is chosen, the sweeping will stop when reaching
to the end point, then each time you press 【Shift】【trig】keys, the sweeping will run once, then
stop on the start frequency and wait for next trigger. External trigger signal could also be chosen,
connect a TTL trigger signal to the 《Trig In 》port on the rear panel of the generator. The
sweeping will run once at the rising edge of each trigger signal. Of course, the period of trigger
signal should be longer than sweeping time.
5.9.5. Sync output
During frequency sweeping, the 《Sync 》port on the front panel output a sync signal. A sync
signal is a pulse wave signal with TTL level, of which the rising edge of the pulse is match along
with the start point of the sweeping, and the falling edge is match along with the middle point of
the sweeping area, the period of the pulse wave is the same with sweeping time.
Under sweeping function, press【Sweep】key(the “Sweep” key-light will be off) to exit frequency
sweeping function and return back to continuous function.
5.10. Burst
It is explained that in burst mode, the word “burst” means the cycle of any waveform, not only the
pulse. In burst output, instrument outputs continuously a series of burst or trigger and output a
single burst according to repeated period, pulse count and start phase set. All the 16 waveforms
listed in the waveforms table could be used as burst waveform. Before entering into burst function,
users should firstly set the waveform, frequency and amplitude value of the burst under CHA
continuous function.
Press 【Burst】key to light “Burst” keyboard indicator, the CHA will output burst signal.
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5.10.1. Repeated Period
Press【Menu】key and select “Period” option, and then set repeated period. Period represents
time from the start of one burst to the start of the next one which must be long enough to contain
the pulse numbers of setting, as the following formula shows:
Repeated period＞(Pulse count / Pulse frequency)
If the repeated period setting is too short, the instrument will modify it to the allowable minimum
value.
5.10.2. Burst count
Press【Menu】key and select “Ncyc” option, and then set the burst count. Burst count represents
the number of cycles of burst in a repeated period, which must be small enough to be contained
in one repeated period, as following formula shows:
Pulse count＜(repeated period ×pulse frequency)
If the burst count setting is too big, the instrument will modify it to the allowable maximum value.
5.10.3. Start phase
Press【Menu】key and select “Phase” option, and then set start and end phase value. The start
and end of the burst are always on the same phase of the waveform, this phase is named as the
start phase. The start phase setting range is 0° to 360°, it is not available to square wave.
5.10.4. Trigger source
Press【Menu】key, select “Source” option and set trigger source, there are only two values to
choose. Set the value as 0 to choose internal trigger source, and set it as 1 to choose external
trigger source. When choosing external trigger source, burst output will stop, then each time you
press 【Shift】【trig】keys, the generator will output a burst, then keep on the start phase and
wait for next trigger. External trigger signal could be chosen as well, connect a TTL trigger signal
to the 《Trig In》port on the rear panel of the generator. The generator will output a burst at the
rising edge of each trigger signal, then keep on the start phase and wait for next trigger. Of
course, the period of the trigger signal should accords with the limitation condition of repeated
period setting. When external trigger source is chosen, the setting of repeated period is ignored.
5.10.5. Sync output
During burst output, a sync signal can be outputted from the front panel “Sync” connector. It is a
TTL level’s pulse wave, its rising edge is corresponding to the burst starting point, while the
falling edge is corresponding to the end of the burst. That is to say, during the continuation of
burst, sync output keeps high level; during the stop period of burst, sync output keeps at low level.
In burst function, press 【Burst 】key again, the “Burst” keyboard indicator will be off, the
generator exits burst function and returns back to continuous function.
5.11. Arbitrary waveform
The generator could output 16 kinds of waveforms(see waveform sequence number table), where
0#～10# are internal fixed waveforms, which the users could only use but not edit or make any
change to, 11# ～15# are user-defined waveforms, the users may edit arbitrary waveforms by
themselves, or edit and change current waveforms.
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