PeakTech TFG1900A Series User manual

User’s Guide
TFG1900A Series Function/Arbitrary
Waveform Generators
Shijiazhuang Suin Instruments Co.,Ltd. 08/2011

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
Shijiazhuang Suin Instruments Co., Ltd 1
Introduction of TFG1900A Series Function/Arbitrary
Waveform Generators
The present guide is valid for three models of TFG1900A Series Function/Arbitrary
Waveform Generators:
TFG1903A, TFG1905A, TFG1910A and TFG1920A, the highest sine wave frequency of
which are respectively 3MHz, 5MHz, 10MHz and 20MHz.
With Direct Digital Synthesis (DDS) technology, the TFG1900A Series
Function/Arbitrary Waveform Generators are 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 generators are of 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 20ppm, 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

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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

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
Shijiazhuang Suin Instruments Co., Ltd 3
TFG1900A Series Function/Arbitrary Waveform Generators and accessories
TFG19xxA Series Function/Arbitrary Waveform Generator 1
3-core power cord 1
CD 1
And the following contents are included in CD:
USB Driver programmer
Remote control demonstration software
Waveform edition software
User’s Guide
Programmers’ Guide
Waveform edition instruction
Interface usage instruction

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
Shijiazhuang Suin Instruments Co., Ltd 4
Summary of this Guide
Chapter 1 Getting started
To learn the basic operation of the generator now.
Chapter 2 Principle introduction
To describe the basic working principle of the generator.
Chapter 3 Reference
To introduce the functions, operations and applications of the generator in detail.
Chapter 4 Service and support
To promise warranty and technological support of the generator.
Chapter 5 Specification
To list the function characteristics and specifications of the generator.
Note: This document is just a guide of operation of this instrument, it is unavoidable for not-so-adequate
description of technology and wrong printing, please excuse any modification of the contents
without special notification.

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Content
Chapter 1 Getting started ---------------------------------------------------------------------5
Prepare the generator for use -----------------------------------------------------------5
Front and rear panel ---------------------------------------------------------------------6
Display introduction --------------------------------------------------------------------7
Keyboard introduction ------------------------------------------------------------------7
Basic operation --------------------------------------------------------------------------9
Chapter 2 Principle introduction ------------------------------------------------------------13
Principle diagram of the generator ----------------------------------------------------------------13
DDS working principle -----------------------------------------------------------------------------13
Control working principle--------------------------------------------------------------------------14
Chapter 3 Reference --------------------------------------------------------------------------15
Data input --------------------------------------------------------------------------------------------15
CHA continuous ------------------------------------------------------------------------------------15
CHB continuous ------------------------------------------------------------------------------------19
FM-----------------------------------------------------------------------------------------------------20
AM-----------------------------------------------------------------------------------------------------21
PM-----------------------------------------------------------------------------------------------------22
PWM--------------------------------------------------------------------------------------------------23
FSK----------------------------------------------------------------------------------------------------25
Frequency sweeping function ---------------------------------------------------------------------26
Burst---------------------------------------------------------------------------------------------------27
Arbitrary Waveform---------------------------------------------------------------------------------29
Setting parameter storage--------------------------------------------------------------------------31
External memory------------------------------------------------------------------------------------32
Frequency Measurement---------------------------------------------------------------------------32
Output port ------------------------------------------------------------------------------------------33
Input port---------------------------------------------------------------------------------------------35
Communication Port-------------------------------------------------------------------------------35
Parameter calibration -------------------------------------------------------------------------------35
Default setting ---------------------------------------------------------------------------------------37
Firmware version -----------------------------------------------------------------------------------37
Chapter 4 Service and support -----------------------------------------------------------------------38
Chapter 5 Specifications ------------------------------------------------------------------------------39

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
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Chapter 1 Getting started
The front and rear panels, operations and functions of the TFG1900 series 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:
1.1 Prepare the generator for use
1.1.1 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.
1.1.2 Connect to power supply
Boot the generator only under the following conditions.
Voltage:AC 100～240V Frequency: 45～65Hz
Power consumption: ＜30VA
Temperature: 0～40℃Humidity: ＜80％
Plug the attaching plug into an AC100~240V 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.

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1.2 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
1.3 Rear panel
1. Modulation in 2. Trig in 3. Count in 4. Fan
5. Power socket 6. USB Device 7. USB Host

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
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1.4 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.
1.5 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.
【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.

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
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【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
1.6 Basic operation

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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.
1.6.1 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 “Vdc” unit, press【-】【1】【Vdc】.
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(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】【#】.
1.6.2 CHB continuous: CHB outputs stable and continuous signal with continuous.
Press【Shift】【CHA/CHB】key, select “CHB” option and set CHB parameters.

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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.
1.6.3 Frequency modulation function: set the CHA continuous as 20kHz 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.
1.6.4 Amplitude modulation function:
Press【AM】key to output amplitude modulation signal.
Modulation frequency setting: set modulation frequency as 1kHz
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.
1.6.5 Phase modulation function:
Press【PM】key to output phase modulation signal.
Modulation frequency setting: set modulation frequency as 10kHz
Press【Menu】key, select “Mod_f” option and press【1】【0】【kHz】.
Phase deviation setting: set phase deviation as 180°

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
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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.
1.6.6 Pulse 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.
1.6.7 Frequency shift keying function: set waveform as sinewave
Press【FSK】key to output frequency shift keying signal.
Hop rate setting: set hop rate as 1kHz
Press【Menu】key, select “Rate” option and press【1】【kHz】.
Hop frequency setting: set hop frequency as 2kHz
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.
1.6.8 Frequency sweeping function:

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Press【Sweep】key to output frequency sweeping signal.
Start frequency setting: set the start frequency as 5kHz
Press【Menu】key, select “Start” frequency and press【5】【kHz】.
End frequency setting: set end frequency as 20Hz
Press【Menu】key, select “Stop” and press【2】【0】【Hz】.
Sweeping time setting: set sweeping time as 5s
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.
1.6.9 Burst function: set continuous as 1kHz
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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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.
2.1 Principle diagram of generator
2.2 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
Micro-controller
MCU
Digital synthesis
FPGA
Digital-analog
converter D/A
Amplitude control
Offset control
Clock
20MHz
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

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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.
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.
2.3 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.

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Chapter 3 Reference
3.1 Data input
3.1.1 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.
3.1.2 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.
3.1.3 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.
3.2 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.

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3.2.1 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.
3.2.2 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.
3.2.3 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|)
3.2.4 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.
3.2.5 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

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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.
3.2.6 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 50Ω output 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.
3.2.7 Offset setting Press【Offset】key, the light of which will be on, press “Vdc”
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

TFG1900A Series Function/Arbitrary Waveform Generators User’s Guide
Shijiazhuang Suin Instruments Co., Ltd 19
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.
3.2.8 DC voltage output Set amplitude at 0V, the offset value could be set
arbitrarily within ±10V range, the generator is now a DC voltage power supply and
outputs specified DC voltage signal.
3.2.9 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
3.2.10 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,