The SynthHD is a state of the art Dual Channel RF Signal Generator. These devices have set the bar on microwave radio frequency generators for quality, size and price. As always, our products are designed and manufactured in the USA!
Tune any frequency between 10MHz and 15GHz in 0.1Hz resolution. Adjust calibrated amplitude in 0.1dB resolution up to +20dBm and across more than 50dB of range. Each channel has an independent frequency and amplitude settings, or set both channels to the same frequency and adjust phase between the two in 0.1 degree increments.
Expect excellent performance and high reliability despite the SynthHD Pro’s low cost.
The SynthHD is a 10 MHz to 15 GHz dual channel software tunable RF signal generator and frequency sweeper controlled and powered by a device running Windows or Android via its USB port. The SynthHD ’s dual independent channels can be configured to run as two different frequencies, or the same frequency with different phases. This allows its use in antenna beam steering applications or quadrature signal generation commonly used in image reject frequency conversion.
The SynthHD also has nonvolatile onboard flash memory so it can be programmed to fire up by itself on any frequency, power, sweep or modulation setting (and combinations thereof) to run without a PC in the field. This makes for a highly mobile, low power, and lightweight solution for your RF signal generation needs.
10 MHz to 15 GHz in 0.1 Hz steps
-50 dBm to +20 dBm in 0.01 dB steps
Set each channel to independent frequencies and amplitudes
0 to 360 degrees coherent phase control in 0.01 degree steps on each channel
Stack multiple devices for coherent phase control on every channel
Select internal 10 or 27MHz reference or use external 10-100MHz reference
Pulse, AM, and FM internal modulation including FMCW radar chirp
Pulse Modulation with 1uS minimum width and 1uS resolution
Pulse, AM, and FM external modulation from DC – 10KHz
Powerful Trigger modes allow external triggering of most functions without a PC connected
Linear and list mode (frequency and amplitude hopping) sweeps include dual channel differential sweeps
Save all settings to the device for use without a PC
32 bit ARM processor onboard which is Arduino compatible
Complete Labview GUI executable and source code (pictured below) included with purchase
Windows, Linux, and Android compatibility
Designed and manufactured in the USA with maximized value and cost ratio
Contact us for custom firmware and hardware options.
SynthHD Software GUI (LabVIEW source code included with purchase)
The following video shows the SynthHD doing a Pulsed FM Radar Chirp (FMCW) that is simultaneously AM modulated.
The video below is taken with both channels driven into a mixer. The mixer is then fed into an oscilloscope and displayed on the right side of the video. The signal shows the DC and near DC downconverted component. The DC level depends on the phase relationship between the two channels. The switch on the far right of the GUI toggles between controlling channels (RFA or RFB).
For orders over 10 units discounts will apply. Request a quote here. Emails will be answered within 24 hours. Keep an eye on your SPAM folder. You will be given a lead time and a quote if you desire large volume.
7 × 5 × 2 in
Dual independent channels
Calibrated from 10MHz – 15GHz
Open source LabVIEW GUI software control via USB
Run hardware functions with or without a PC
32-bit ARM processor onboard
Two channel frequency, phase, and amplitude control
Quadrature (or other phase) LO signal generation
1Hz frequency resolution
01 degree phase control on each channel
100uS RF lock time standard
Up to +20dBm output power
01dB amplitude resolution
Over 50dB of power control
Absolute power display on Software GUI
10MHz – 100MHz external reference input
Selectable 10 or 27 MHz internal reference output
5ppm internal reference accuracy
Internal and external FM, AM, Pulse Modulation
Pulsed FMCW Chirp
External sweep, step, and modulation trigger
500 point frequency and amplitude hop table
Dual channel frequency and amplitude lock
Channel enable and disable saves energy
5 ultra-low noise linear regulators on board
5 X 2.15 inches not including RF connectors
USB or UART control via USB-C connector
1. USB and UART Warning
The SynthHD v2 was designed to work with, and ships with, a USB 2 cable. Use a USB 3 cable only when tapping into the UART signals for 3.3V COM port control of the SynthHD with your own microcontroller circuit. Using a USB 3 cable attached to a USB 3 port on a PC may have unknown consequences as the PC is not designed to see the SynthHD UART signals and vv. See UART app note for UART usage instructions.
2.1 Electrical Characteristics
Suggested 2A minimum
420mA per channel
Standby Supply Current
Both RF channels OFF
RF Output Frequency Range
Calibrated Frequency Range
RF Output Power Maximum
RF Output Power Minimum
RF OFF Output Power
100% shutdown of RF section
RF Frequency Resolution
Default is 100Hz selectable by Channel Spacing Setting
RF Output Power Resolution
RF Phase Resolution
** See note 1
RF Output Impedance
Internal Reference Frequency
10 or 27
Internal Reference Tolerance
External Reference Frequency
Keep phase comparator less than 100MHz
External Reference Level
Keep below 3.3Vpp
Internally pulled up
Note 1: Phase tuning speed, phase resolution and carrier frequency are inter-related. Phase tuning speed slows as RF carrier frequency and Channel Spacing settings decrease. Smaller Channel Spacing will have higher phase and frequency resolutions but slower phase tuning speed. Going below 100MHz carrier with smaller Channel Spacing than 100Hz may be prohibitively slow and/or erratic.
2.2 Thermal Operating Characteristics
Without airflow or heatsinking
Query internal temperature sensor with software and keep below 75C with airflow, heat sinking or limited duty cycle.
3. Typical Performance
3.1 RF Output Power
The typical output power (per channel) of the SynthHD is shown below. This graph is of raw unleveled operation at both the maximum and minimum gain settings of the output variable gain section. Gain is set via dBm power commands allowing output power levels anywhere in the range between the minimum and maximum levels shown below. RF port power and frequency can be set independent of each other. Power levels are settable in 0.01dBm increments. On board calibration is attained through a look up table for each channel. Device calibration is performed at the factory and stored in onboard flash memory. Calibration is good from 10MHz to 20GHz. Operation from 20GHz to 15GHz is uncalibrated and unspecified. All parts of the signal chain have high quality voltage regulation, and the D/A’s driving the VGAs have a 1% voltage reference controlling their outputs.
3.2 RF Output Harmonic Content
The typical SynthHD harmonic distortion is shown below for the second and third harmonics. This data is taken at a leveled fundamental power of 0dBm.
If lower harmonic levels are needed, Windfreak Technologies suggest the use of low cost SMA filters from Crystek and Minicircuits.
Port to port isolation is shown below with both channels at 0dBm output power. One trace is taken with a 3MHz offset between channels. The other trace is taken with a 20KHz offset between channels. The 20KHz offset places each signal within each other’s loop bandwidth and the leakage modulates each other’s VCO control voltages where loop gain is high. Offsets inside the loop bandwidth will have worse isolation. The below data is taken with both PLL_ICP settings at 15.
Note: The plot above shows the conducted port at 5.0 GHz. The terminated port is set at 5.001 GHz. The spur location is at a 2MHz offset since the SynthHD uses an RF divide by 2 circuit to achieve 5GHz. As the RF frequency decreases, the isolation spurs move out, until they are eventually outside of the loop bandwidth and thus significantly attenuated.
3.4 Integer Boundary Spurs
A mechanism for in band fractional spur creation in all fractional PLL’s is the interactions between the RF VCO frequency and the internal 27MHz, internal 10MHz or arbitrary external reference frequency. When these frequencies are not integer related, spur sidebands appear on the VCO output spectrum at an offset frequency that corresponds to the difference in frequency between an integer multiple of the reference and the VCO frequency. These spurs are attenuated when outside the loop filter which is 30KHz wide. By having two selectable internal reference frequencies of 10MHz and 27MHz the problem is eliminated by switching reference frequencies when working around a boundary.
Example if using the SynthHD 27MHz internal reference: For the fundamental VCO range of 3400MHz to 6800MHz the first integer boundary happens at 27MHz X 126 = 3402MHz, the next at 27MHz X 127 = 3429MHz and every 27MHz thereafter up to 6777MHz. Above and below the fundamental VCO band the spacing will be affected by the RF doubler or RF divider respectively. If the desired VCO operating frequency is 3402.01MHz this would give spurs 10KHz on either side of the carrier that may be unacceptable. In this case, using the 10MHz reference would be suggested since its closest integer boundary is at 3400MHz. Spurs 2MHz away will be attenuated to satisfactory levels by the loop filter.
3.5 Phase Noise and Jitter
3.6 Intermodulation Distortion after an External Wilkinson Combiner
It’s possible to lock both channels in both frequency and amplitude for easy tuning during IMD testing of IP3 in passive and active components. The plot below shows two tones combined with a YL-70 0.5-2.0 GHz KL combiner that has roughly 20dB of isolation between ports. The tones are centered at 1GHz and separated by 1MHz. This method will allow for IP3 testing below roughly +40dBm.
3.7 Performance over Temperature
The SynthHD has an algorithm to reduce amplitude drift over temperature. The user can specify 4 different control settings in the firmware.
No temperature compensation
Compensation only during a frequency or amplitude setting
#1 plus periodic adjustments every 1 second
#1 plus periodic adjustments every 10 seconds (factory default)
Temperature compensation 2 and 3 are turned off during active modulation. Frequency sweeps and hops are only compensated for each step unless the setting is 0.
All subsequent temperature plots are based on an internal temperature measurement with temperature compensation turned ON. When the SynthHD has one RF channel turned on in a lab environment with moderate air flow at 25°C the internal temperature will usually be around 40°C.