Quartzlock E6-SS Instruction Manual

Model E6-SS Operation Manual
E6-SS Manual A5 29 September 2015
Page 1
E6-
Desk Top Universal Reference Source
USER’S HANDBOOK
Quartzlock UK Ltd
Gothic, Plymouth Road, Totnes, Devon. TQ9 5LH, England.
Tel: [phone]
Web: www.quartzlock.com E-mail: [e-mail]

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Revision
Date
Description
By
1
12th Aug 2015
Initial Release
N. Law

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Contents
1Safety Considerations ..............................................................4
1.1 General............................................................................ 4
1.1.1 Before Applying Power............................................4
1.1.2 Before Cleaning.......................................................4
1.2 Voltage, Frequency and Power Characteristics...............5
1.2.1 Universal Full Range AC Input Power Adaptor .......5
1.2.2 Unit Power Requirements........................................ 5
1.3 Environmental Conditions................................................5
1.3.1 Temperature............................................................5
1.4 Cleaning Instructions .......................................................5
2Desk Top Universal Reference Source ....................................7
2.1 Universal Reference Source............................................7
2.1.1 Introduction..............................................................7
2.1.2 Technical Description..............................................7
3Operating Procedure..............................................................12
3.1 Connection to power supply...........................................12
3.2 Connection to interface..................................................12
3.3 Control codes.................................................................12
3.3.1 General instructions ..............................................12
3.4 Calibration...................................................................... 13
3.4.1 Internal reference frequency calibration................14
3.4.2 RF level accuracy calibration ................................ 14
3.4.3 Low range RF level interpolation calibration......... 15
3.4.4 AM depth calibration..............................................16
4Specification...........................................................................17
5Unit Outline.............................................................................22
6Accessories............................................................................ 23
6.1 Plug Top Supply.............................................................23
Appendix A...................................................................................... 24

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1 Safety Considerations
1.1 General
This product and related documentation must be reviewed for familiarisation
before operation. If the equipment is used in a manner not specified by the
manufacturer, the protection provided by the instrument may be impaired.
1.1.1 Before Applying Power
Verify that the product is set to match the available charger and the correct
fuse is installed.
1.1.2 Before Cleaning
Disconnect the product from operating power before cleaning.
WARNING
Bodily injury or death may result from failure to heed a
warning. Do not proceed beyond a warning until the
indicated conditions are fully understood and met.
CAUTION
Damage to equipment, or incorrect measurement data,
may result from failure to heed a caution. Do not proceed
beyond a caution until the indicated conditions are fully
understood and met.

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1.2 Voltage, Frequency and Power Characteristics
1.2.1 Universal Full Range AC Input Power Adaptor
Class II power (no earth)
Overvoltage, short circuit & over temperature protection
GS, UL/cUL & CE approval
Voltage 100 - 240V AC
Frequency 50 - 60Hz
Power characteristics 600mA Max
Output Voltage 15V DC 1.2A
1.2.2 Unit Power Requirements
Input Voltage 11Vdc –18Vdc
Input Current 600mA max
1.3 Environmental Conditions
1.3.1 Temperature
Operating (ambient)
-20oC to +50oC
Charging
0oC to +45oC
Storage
-20oC to +40oC
1.4 Cleaning Instructions
To ensure long and trouble free operation, keep the unit free from dust and
use care with liquids around the unit.
Be careful not to spill liquids onto the unit. If the unit does get wet, turn the
power off immediately and let the unit dry completely before turning it on
again.
Never spray cleaner directly onto the unit or let liquid run into any part of it.
Never use harsh or caustic products to clean the unit.

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2 Desk Top Universal Reference Source
2.1 Universal Reference Source
2.1.1 Introduction
The instrument is a synthesized source optimised for signal purity. A wide
range of output frequencies is provided, at output levels between –18 and
+13dBm. Various analogue and digital modulation modes are available.
The instrument is powered from a 12V DC supply with a maximum power
consumption of 6 watts.
A USB interface is provided. Communication can either use a set of simple
control codes, or a front end Windows graphic interface.
2.1.2 Technical Description
A block diagram is shown in FIG1
FIG 2 shows the front and rear panel layouts.
The basis of the source is two single chip fractional N synthesizers with built
in VCOs.
The first synthesizer (reference synthesizer) generates an intermediate
reference frequency between 50MHz and 56.5MHz in steps of 0.5MHz. The
reference input to the reference synthesizer is either the internal TCXO at
20MHz, or the external reference input at 10MHz. The reference synthesizer
operates in integer mode. The phase comparison frequency is 10MHz. The
VCO operates between 2GHz and 2.26GHz. The internal divider is 40.
The second (main) synthesizer generates directly the high range of output
frequencies between 100MHz and 3GHz. The internal VCO operates
between 1.5GHz and 3GHz, and lower frequencies are generated by binary
division using the internal divider. The divider range is 2 to 62. When using
the divider, the output is close to a square wave.
The low range of frequencies from 380kHz to 100MHz are generated by
external binary dividers with ratios between 2 and 64. ECL dividers are used,
with differential outputs.

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With predominately square wave outputs from the dividers, the second
harmonic is theoretically suppressed, however the third harmonic is only -
9.5dBc. Therefore all outputs are filtered to achieve harmonics at about -
40dBc.
On the high range, the filters are monolithic low pass filters switched by FET
switches. On the low range, the filters are discrete component filters
switched by PIN diodes.
On the high range, amplitude is set by an internal gain control in the main
synthesizer chip. This has steps of 1dB.
On the low range, amplitude control is achieved by varying the current in the
output emitter followers of the ECL dividers. The setting is made by a 10 bit
DAC controlled by the microcontroller.
The main level control is a monolithic FET switched attenuator with a range
of 0 to 31.5dB in 0.5dB steps. This is followed by an output amplifier.
The main synthesizer may be operated in integer, fractional, or exact
frequency modes. The mode is automatically selected by the software.
Integer mode is used when there is an integer relationship between the phase
comparison frequency and the VCO frequency. Fractional mode is used
when there the VCO frequency is not an integer multiple of the phase
comparison frequency. Fractional mode is more susceptible to spurious
outputs. The most problematic spurs occur when a multiple of the phase
comparison frequency falls within a loop bandwidth (~200kHz) of the VCO
frequency. These are called integer boundary spurs. The use of an
intermediate reference frequency (50MHz to 56.5MHz in 0.5MHz steps)
enables integer boundary spurs to be avoided.
Generally fractional frequency mode does not allow exact decimal
relationships between an external reference frequency and an output
frequency. For example, a required output frequency of 2.048MHz will
actually generate an output frequency of 2.0480000018MHz. This can be a
serious problem when generating specific reference frequencies from a
frequency standard.
Exact frequency mode is a modification of fractional mode that enables exact
decimal relationships with output frequencies entered with a resolution of
1kHz or less on low range, or 3kHz on high range. For any CW frequency,
the software attempts to use exact frequency mode. If successful, a front
panel LED indicator is lit. In addition a status bit is set in an interface
message.

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Various modulation modes are available, described in detail as follows:
AM.
AM is available on low range only. Depth is adjustable from 0 to 40% in
steps of 1%. AM modulation frequency is adjustable from 1Hz to 20kHz in
steps of 1Hz. AM is achieved by modulation of the low range amplitude
control DAC. The modulation frequency is generated by a software DDS
with a sampling frequency of 65,57377ks/s
FM (internal)
Internal FM is available with deviations up to 0.5% of the centre frequency,
adjustable in 1Hz steps. Modulation frequency is adjustable from 1Hz to
20kHz in 1Hz steps. Internal FM is achieved by direct modulation of the
synthesizer fractional divider. The modulation offsets are generated by a
software DDS with a sampling frequency of 65,57377ks/s. The offsets to the
fractional divider have 16 bit quantization.
As no baseband filter is used after the software DDS, aliased copies of the
modulation spectrum will be present at multiples of the sampling frequency.
These are typically- 50dB relative to the main response.
FM (external)
DC coupled external FM is available by supplying a suitable modulation
waveform to the external modulation input BNC socket on the rear panel.
The input range is ±1Volt for calibrated deviations, and ±1.25V clipping
level. The input impedance is 1kohm.
The input waveform is sampled at a 40ks/s rate using a 12bit ADC. The
result is then scaled by the selected deviation, and is used to directly
modulate the synthesizer fractional divider. As no baseband filter is used, the
modulation spectrum will repeat at multiples of the sampling frequency,
typically at a level of –50dB relative to the main response.
FSK (external)
Frequency shift keying is available by applying a logic input to the external
modulation input on the rear panel. The logic levels are TTL or 3.3V
CMOS. A logic 0 produces a negative frequency shift, and a logic 1 a
positive shift. The total frequency shift is that programmed for internal FM
deviation. i.e., a programmed deviation of 10kHz produces a frequency shift
of ±5kHz. The maximum baud rate is about 35kbaud. If the maximum rate is
exceeded, data bits will be skipped.

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ASK (external)
Amplitude shift keying is available by applying a logic input to the external
modulation input on the rear panel. The logic levels are TTL or 3.3V
CMOS. A logic 0 gives the attenuated level, and a logic 1 the full level. The
shift is applied relative to the CW RF level. i.e., if a CW level of 10dBm is
programmed, then an ASK shift of 10dB results in a low level of 0dBm, and
a high level of 10dBm. If the low level is less than –18dBm, then the low
level will use the carrier disable function, which will give a low level equal to
the carrier disable level, typically –80dBm. The maximum baud rate for ASK
is about 60kbaud.
SWEEP
A flexible frequency sweep mode is provided. This is controlled with three
parameters, start frequency, stop frequency, and sweep time. The start and
stop frequency may be any frequency within the total operating range of
380kHz to 3GHz. The stop frequency must be greater than the start
frequency. The sweep time must be between 10ms and 50 seconds. The
number of points will be automatically calculated as sweep time divided by
100us, or 1000 points maximum. Band changes will occur as the sweep
crosses band edges. These band changes will result in a short amplitude
glitch lasting typically 200us. Fast sweeps across band edges should be
avoided. A sync pulse is available at the rear panel modulation input. This
occurs at the start of each sweep, and has a high level of 2.4V, and a
duration of about 30us.
PHASE ADJUST
The phase adjust mode is only useful if two signal source units are used. If
these are locked to the same external reference using a power splitter, then
the relative phase between the two outputs may be adjusted if both units are
set to the same frequency. Note that exact frequency mode cannot be used,
and will be disabled automatically. This means that the output frequency will
not have an exact decimal relationship to the external reference.
The external reference input on the rear panel accepts a 10MHz sine wave
reference. The external reference should be at a level of 7dBm to 13dBm for
optimum phase noise. The input impedance is 100ohms. The presence of the
internal reference is detected automatically, and if present an LED is lit on
the front panel. The external reference replaces the internal TCXO reference,
rather than phase locking the internal reference. This means that the external
reference phase noise will directly affect the output phase noise over the
range of the loop bandwidth, approximately 0Hz to 200kHz.

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One of the design objectives was that the source could be used without the
interface connected. This can be useful when the source is used to supply a
few frequencies that are not often changed. In order to achieve this, 5 user
memories are provided. One of these is the power on memory, automatically
recalled at power on, and the other 4 are user memories which may be
recalled using a front panel control.
Power on memory.
The power on memory stores CW frequency, RF level, and all modulation
parameters (except phase adjust parameters). However the modulation mode
is always set to CW on power up. Therefore the power on memory can only
be used to store a CW frequency.
The power on memory is refreshed every 1.193 hours, and is set to the
current instrument status, irrespective of whether the interface is connected
or not.
User memories.
The user memories can only be refreshed with the current instrument status
using an interface command. A user memory can be recalled using an
interface command, or by using the front panel pushbutton. This cycles
through all four user memories. The use of a memory is indicated by a lit
LED on the front panel. If the instrument status is changed using an interface
command, the memory LEDS are turned off to show that the memories may
not reflect the current instrument status. The user memories store the CW
frequency, RF level, modulation parameters, and the modulation mode.

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3 Operating Procedure
3.1 Connection to power supply
The supplied line adapter can be used to power the instrument from AC line
power.
Alternatively any good quality DC supply may be used. DC supply voltage is
10 to 15V, and power consumption about 6W. At 12V, current is about
500mA. The centre pin of the power connector is positive.
WARNING
Reverse polarity may cause damage.
3.2 Connection to interface
The USB interface uses a FT230X interface chip made by FTDI. The first
connection of the instrument should result in the usual Windows dialog, and
the driver should be found on the internet automatically. If this does not
happen, the correct driver to suit the operating system in use should be
downloaded from the FTDI website, and installed.
The interface driver will create a virtual port, which should appear in the port
list accessed by Device Manager. A terminal program such as HyperTerm
can then be used to control the instrument using the control codes.
Alternatively, the custom GUI supplied can be used. This will have its own
operating instructions.
3.3 Control codes
This section covers in detail the use of the interface control codes.
3.3.1 General instructions
All control codes use upper case. All commands start with two characters.
Most commands have an interrogative form, where a “?” is appended to the
command. Some two character commands immediately initiate an action
without further input. With some commands, a third character immediately
initiates an action without further input. A successful input always results in
a carriage return response. An incorrect command or sequence results in an

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“!” and a carriage return. (Note that when using HyperTerm, the option to
append a line feed to a received carriage return should be used).
Examples:
FR? Interrogates current CW frequency and frequency step
FRI Increments current CW frequency by frequency step
EU update EEPROM with all user and calibration data
There are two types of data entry used by commands:
Those which expect a fixed length hexadecimal string, and do not require a
terminator character such as a carriage return or enter. Examples:
SM1 Store instrument status to user memory 1
Those which expect a variable length decimal or character string. A decimal
string may contain special characters such as sign, decimal point, and
multiplier, and terminates with a carriage return (enter). The string is always
preceded by a space. Examples:
FR (space) 10.23M (carriage return) enters 10.23MHz
MM (space) FSK (carriage return) sets modulation mode to FSK
RF (space) –18.0 (carriage return) sets RF level to –18dBm
FST (space) 20k (carriage return) sets sweep time to 20 secs
The following frequency and time multipliers are accepted:
k, K, M, G
Some commands accept a standard floating point string, which may include
“e” or “E”, however it is never necessary to use the exponent form.
A full list of available commands is given in Appendix A. Some of these
commands are intended for development or debug. In this section the
commands likely to be used frequently by the user are described.
3.4 Calibration
All calibration is closed case. There are no adjustments on the PC board.
The following adjustment procedures are possible:
a) Internal reference frequency calibration

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b) RF level accuracy calibration
c) Low range RF level interpolation calibration
d) AM depth calibration
3.4.1 Internal reference frequency calibration
Procedure:
Connect the instrument RF output to a frequency counter with an internal or
external reference of accuracy better than 1 in 108.
Set RF level to 10dBm, and CW frequency to 100MHz.
Allow 1 hour warm up from power on.
The TCXO tuning is accessed using the SS command. SS? will return the
synthesizer status bytes. The fourth byte is the internal reference tune. New
tune bytes should be entered using the SSTdd command until the output
frequency is within 1E-7 of 100MHz (±10Hz).
Finally the new tune value should be saved to EEPROM using the EU
command.
3.4.2 RF level accuracy calibration
For this procedure a power meter with recorder output is used. A suitable
power meter is the HP435B, HP436A, or HP437B with appropriate sensor
type 8482A.
Procedure:
The sensor is connected directly to the instrument RF output connector using
a suitable adapter.
The recorder output from the power meter is connected to the rear panel
modulation input.
Initial settings for the instrument are: RF level 13dBm
The power meter should be calibrated, and its CF setting adjusted to the
individual power sensor calibration for 50MHz. It is not possible to adjust
the power meter calibration during the automatic procedure. It is now
necessary to get a reading of 13.0dBm ±0.1dB on the power meter. This can
be done by trying various centre frequencies on the instrument, or by
connecting the power meter to another adjustable RF source of any
frequency. The objective is to relate the recorder output to a measured

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power of 13dBm. Once the reading is correct, send the following commands
to the instrument:
SSB05 This activates board test 5
Now press the “C” key. This returns a number that relates to the DC voltage
on the external modulation input, i.e. the DC voltage that corresponds to a
power of 13dBm
Repeat last step until the reading is stable.
Now if necessary reconnect the power meter to the instrument RF output
Finally press the “L” key. The automatic calibration of the low range will
now start. This will take about 10 minutes to complete.
The calibration setting (CF) on the power meter can now be adjusted to a
value that is close to the mean response for the band 100MHz to 3GHz. A
value for 1GHz is suggested.
Now press the “H” key. The automatic calibration of the high range will
start.
When this is complete, press the “S” key. This will write the new calibration
tables to EEPROM.
Finally press the “E” key to exit board test 5.
(Note: After this procedure the original CW frequency will have been
overwritten)
3.4.3 Low range RF level interpolation calibration
The low range uses the power control to interpolate the 0.5dB attenuator
steps. This varies from one band to another, so a calibration table is used to
set the interpolation steps. This has only 1 entry for each band
Procedure:
Set the RF level to 13dBm.
Connect the power meter directly to the instruments output connector.
Send the following command:
SSB04 This activates board test 4
Press key “N” until the first calibration frequency is shown (1MHz)

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The two keys “0” and “1” switch the power control increment by 1dB. The
objective is to adjust the calibration table so the increment measured on the
power meter is also 1dB. The calibration table is incremented and
decremented using the “+” and “-” keys (on the numeric keypad).
The attenuation increment should be set to 0dB, and the power meter
reading noted. The power control increment is then set to 1dB, and the
calibration value varied until the power meter reading has decreased by 1dB
also.
Key “N” selects the next frequency, and the above procedure is repeated.
The final frequency is 60MHz.
At the end of the calibration, press key “S” to save the calibration table in
EEPROM. Finally press key “E” to exit the routine.
3.4.4 AM depth calibration.
This calibration uses a modulation meter, or other modulation analyser.
Suitable types are Racal 9009 or Marconi TF2304. A modulation analyser
such as HP8901 can also be used.
Procedure:
Set the instrument to AM, 30% depth, 10MHz. RF level 13dBm.
Connect the modulation meter to the instruments RF output.
Send the following command:
SSB03 activates board test 3
Use the “N” key to select the first calibration frequency (1MHz)
The modulation meter should be reading approximately 30% AM.
Using the “+” and “-”keys, adjust the reading to 30% ±2%
Repeat for all 7 calibration frequencies
Press key “S” to save the calibration table in EEPROM
Press key “E” to exit the routine.

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4 Specification
4.1 Frequency
Coverage: 1MHz - 3GHz
(Under range to 380kHz)
Bands: Range Band no Frequency (note 1) N (note 2)
H 4 1.493GHz to 3.0GHz 1
H 3 755MHz to 1.493GHz 2
H 2 369MHz to 755MHz 4
H 1 184.5MHz to 369MHz 8
H 0 100MHz to 184.5MHz 16
L 6 49.8MHz to 100MHz 32
L 5 25.2MHz to 49.8MHz 64
L 4 12.6MHz to 25.2MHz 128
L 3 6.29MHz to 12.6MHz 256
L 2 3.15MHz to 6.29MHz 512
L 1 1.57MHz to 3.15MHz 1024
L 0 1MHz to 1.57MHz 2048
Frequency resolution:
Band H4 3Hz
Band H3 1.5Hz
Otherwise 1Hz
Frequency accuracy:
Internal reference ±1ppm ± aging
External reference ± resolution
Exact Frequency Mode (EFM) no error (note 3)
Spectral purity:
Harmonics
2nd and 3rd < -30dBc (typically –40dBc)
Subharmonics
Band L6 <-60dBc
Otherwise none
Non harmonics
> 1kHz from carrier <-70dBc (typically <–80dBc)

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Phase noise (10kHz offset), external reference
Band H4 2GHz -100dBc/Hz
Band H3 1GHz -106dBc/Hz
Band H2 500MHz -112dBc/Hz
Band H1 250MHz -118dBc/Hz
Band H0 125MHz -122dBc/Hz
Residual FM (300Hz - 3kHz, ext. reference)
Band H4 2GHz <1.8Hz RMS
Band H3 1GHz <0.8Hz RMS
Band L6 100MHz <0.15Hz RMS
4.2 Amplitude
Coverage: -18.0 - +13.0 dBm into 50ohms
Resolution:
H ranges 0.5dB
L ranges 0.1dB
Accuracy:
H ranges ±1dB
L ranges ±0.5dB
Maximum output (over-range, typical): 16dBm
4.3 Modulation
4.3.1 Internal AM (below 100MHz only)
Type: Stepped sine wave,
Sample rate 65.57377ks/s
Quantization 12 bit
Frequency: 1Hz - 10kHz, step size 1Hz
Depth: 0 - 30%
Depth accuracy: ±10% of setting
4.3.2 Internal FM
Type: Stepped sine wave
Sample rate 65.57377ks/s

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Quantization 16bit
Frequency: 1Hz - 20kHz
Step size 1Hz
Deviation: 0Hz - 0.5% of centre frequency
Step size 1Hz
4.3.3 External FM
Input: Bipolar
1V peak for calibrated deviation
Input impedance: 1kohm
Sampling rate: 40ks/s
Quantization: 12bit
Frequency: DC - 20kHz
Deviation: 0Hz - 0.083% of centre frequency
Step size 1Hz
4.3.4 External FSK
Input: TTL/3.3V CMOS
Data rate: 35kbaud maximum
Frequency shift: ±0Hz - 0.25% of centre frequency
Step size 1Hz
Type unfiltered
2 level
Phase continuous
4.3.5 External ASK
Input: TTL/3.3V CMOS
Data rate: 60kbaud maximum
Amplitude shift:
13dBm output 0.5dB - 31.5dB
Or

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Low range 80dB min (note 7)
High range 60dB min
4.4 Frequency sweep
Type: linear, up
Start frequency: any, within frequency range
Stop frequency: any, within frequency range. Must
be > start frequency
Sweep time: 10ms - 50s in 1ms steps
No of points sweep time/100us or max 1000
Dwell time: 100us min
Sync pulse: TTL, 30us, at sweep start
4.5 Phase adjust (note 8)
Phase increment: 1 - 360degrees in 1degree steps
Increment accuracy: ±0.5 degrees
4.6 External reference
Frequency: 10MHz ±0.1ppm (note 4)
Amplitude: -10 to +15dBm (note 5)
Input Impedance: 100ohm
Spectral purity: Spurii (note 6) <-100dBc
Phase noise: -150dBc/Hz at 10kHz offset
4.7 Power requirements
Voltage: 12V DC ±10%
Supply current: 550mA max