SynthNV - Signal Generator / Power Detector Combo
The Windfreak SynthNV is a 34.4MHz to 4.4GHz software tunable RF signal generator controlled and powered by a
PC running Windows XP, Windows 7, or Android via its USB port. It includes an on board RF power detector which
can be used with the sweep function as a basic RF network analyzer.
The SynthNV also has nonvolatile on board memory so it can be programmed to fire up by itself on any frequency,
power or modulation setting. This makes for a highly mobile, low power and light weight solution for your RF signal
Use this device as a generic RF signal generator in your test setup, or use it as a high quality local oscillator in your
RF / microwave communication system. Simultaneously measure and graph RF power in real time.
Shown below, the software is eloquently engineered giving professional performance at fractions the cost of a bench
top generator.
You may enter data either with the touch pad, knob, directly with the PC keyboard, and also by clicking on arrows
next to the controls.
RF single frequency generation tab.
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RF sweep generation tab. (Step as fast a 550uS per point. Resolution as low as 1KHz per step.)
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RF network analyzer and basic sweeper application. Shown is an actual sweep from a 1167MHz bandpass filter. This
is a throughput measurement. Scroll down for a reflection measurement via Return Loss / VSWR Application Note.
Note: The SynthNV tends to work well with bandpass and lowpass filters but may have errors introduced by the
harmonics when measuring highpass elements.
(This tab uses settings from the Sweep Tab.)
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RF power measurement tab. (Continuously measure broadband RF power at Jll [10].)
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RF Amplitude Modulation tab. (Send burst or continuous AM with modulation rates up to 5KHz. Set the AM
waveform between sinusoid, saw, or ramp. Software writers can even program arbitrary AM waveforms.)
Shown is maximum deviation AM in 0 Hz mode on the spectrum analyzer (time domain).
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RF Pulse Amplitude Modulation tab. (Send burst or continuous pulses with a resolution of 1uS steps.)
Shown (in the frequency domain) is the absolute shortest pulse of 400nS.
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PLL Control tab. (Control some finer details of the ADF4351 to get higher accuracy or quality for a particular
frequency.)
Extras tab. (Check SynthNV firmware version, set Internal or External Reference, save to SynthNV internal EEPROM
memory Frequency, Power, Reference, Modulation and Sweep setup for standalone operation. Also write to the
general purpose digital header pins on the SynthNV, or read analog signals from header pins.)
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Android Controller. (Shown on a Galaxy S4. This program is BETA and supplied on request after purchase.)
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The software is easy to install and use. It can control multiple devices based on programmed serial numbers, do an RF
CW frequency, run an RF sweep, perform basic scalar network analyzer functions, Amplitude Modulate and Pulse
Modulate, save many settings to EEPROM, register real time power measurements on connector [10], and fine tune
the PLL registers for experienced users. Control is very similar to a bench top signal generator. It is also touch panel
friendly.
This software was written in Labview and the open source code is included so that you can modify and enhance any
way you see fit for your own use. Please do not distribute. If you don't own Labview, you will also get an executable
that will install standalone and run on a PC. If you want to write your own software, it is best to get Labview and
reverse engineer the Windfreak Labview source code. Labview is available with a free 1 month trial from National
Instruments. All source code is sent on CD "saved as" using the latest version of Labview Basic. The device is easy to
talk to via 1 simple command character followed program data. For example, setting frequency is done by sending
"f1000.0" (without the quotes).
Please contact us if you want to develop software in Linux. We have a customer who wrote an API that works with the
SynthNV and is sharing it for free.
**The SynthNV has been tested with a terminal program from the Google Play market called "Android USB Serial".
This program will let you send text commands to the SynthNV. The app is currently free. The only hardware it has
been tested with to date is the Samsung Galaxy Note 1, Galaxy Tab 2, and Galaxy s4. To act as a USB host the phone
needs a USB dongle which is about a $15 cable from Amazon. If you have success with your phone or tablet, please
drop us an email so we can add it to the list of compatible hardware. We also have an app shown above that we will
supply for free after you purchase the SynthNV. The SynthNV will also power off of the devices but no testing has
been done on battery life or negative effects on the devices.
Click here to see the format for serial communications via the proprietary Windfreak firmware:
Serial Communication
Both Pulse Modulation and Amplitude Modulation can happen in conjunction with a sweep. You can even program
the SynthNV to do this without the PC when it powers up by itself.
Click here for the operating instructions included with the device:
Instructions
The Hardware:
The technology is based on Analog Devices ADF4351 chip [2] seen here:
Click here for the ADF4351 Datasheet
You can expect high quality RF performance at the RF connector [6] similar to the specs in the datasheet. The only
significant RF difference from the ADF4351 datasheet is that the RF power is up to +19dBm settable in 1/2dB steps
via the Hittite HMC625LP5 chip [5]. This chip is controlled via a high speed 6 bit parallel bus coming from the
microcontroller chip [8].
Click here for the HMC625 Datasheet
RF power (max) into a 50 ohm load is similar to the chart below. (note: amplitude is adjustable via software over 2
amplitude ranges of 30dB in 1/2 dB steps for more than 60dB of adjustment.)
RF generator accuracy is based on an onboard 2.5ppm 10MHz crystal oscillator which is also routed to the outside
world via the reference SMA connector [1]. This connector can also be used to input a higher precision reference if so
desired.
The synthesizer will run off USB power. It will also run standalone via its DC power connector [9] and low dropout
linear regulator [4]. The required voltage is a range from 6-9 volts DC at <300mA, with the center pin being positive
and the outer conductor being ground. 12 volts is possible with enhanced heat sinking on the regulator.
There is also a 1MHz - 4GHz broadband RF power detector enabled by the Analog Devices ADL5513 [11] which is
fed through the SMA connector and 10dB built in attenuator at [10]. This RF detector has up to 70dB of dynamic
range and can measure up to +10dBm of RF power. The software will report real time power measurements or can be
calibrated to show gain over frequency between connector [6] and connector [10] which will give a basic ability to
measure the performance of filters and other RF devices. The display will show RF power vs frequency, or gain vs
frequency much like a lab quality network analyzer. By using an external directional coupler, there is also the ability
to measure the return loss / VSWR of RF devices such as antennas.
Video courtesy of Adam VK4GHZ.
Click here for the ADL5513 Log Detector Datasheet
The Atmel microcontroller [8] is an ATmega32U4 and comes programmed with Windfreak Technologies proprietary
firmware to allow basic control of the whole device. In conjunction with that, it also has the Atmel boot loader so that
custom firmware can be loaded through USB by the end user. Many of the pins from the microcontroller go to .100"
inch headers (not included) spread throughout the PCB. These pins can be configured as generic digital I/O, A/D
convertors, or PWM outputs. All the headers are on .100" inch centers so perf board can be used for prototyping of
special function daughter cards. Other functions that go to these headers are: SPI port, ISP (In System Programming)
port, reset, boot load, and a basic FM analog connection to VCOs vtune port. If you want to use these functions you
will need to install your own dual row .100" inch headers.
Click here for the ATMega32U4 Datasheet
USB communication is done via a virtual comm port directly to the microcontroller. Drivers are included with the
software. The connector [7] requires a USB mini cable (not included).
Included with all of this are softcopies of the PC board schematics and a PCB reference designator map on the CD.
This way you can see what bus wires are used to control the synthesizer chip and PA. You will also see what
microcontroller pins are routed to headers. This helps with custom firmware development.
Note: Please look under the pink foam in the shipping box for the CD and instructions.
On board the PCB are 4 troubleshooting LEDs: one that shows USB power, two generic LEDs [3] from the
microcontroller, and one that shows phase lock on the programmed frequency. The generic LEDs will blink differently
with different commands. They will also show errors when the command is not understood. This helps with custom
software development.
Compare this unit to other solutions worth thousands of dollars. We've invested hundreds of man hours on software
that you get to build upon for highly custom applications.
Some applications include: wireless communications systems, microwave point to point backhaul radios, Software
Defined Radio (SDR), radar, Automated Test Equipment (ATE), EMC - radiated immunity pre-compliance testing,
sweeping and hopping, Scalar Network Analyzers (SNA), complex waveform electronic warfare (EW), Phase Lock
Loop (PLL) Synthesizer