VDI Synthesizer•8-20GHz Synthesizer•Fast switching speed•

Frequency sweeping•

Excellent phase noise•

USB control with software
Product Description

Phase Noise @ 16.3 GHz, 10MHz Ref

VDI synthesizers were designed specifically for VDI sources andreceivers with features targeted for Terahertz applications. The
frequency range of 8-20 GHz and power of 17dBm is compatible
with most VDI multiplier chains. The synthesizer offers
competitive phase noise and 20 Hz frequency resolution in a~6.25x4.5x1.5” package. The frequency can be controlled by aPC through a USB connection with software provided. Stepping
the continuous wave frequency using USB commands can beaccomplished in 1mS for step sizes as high as 40MHz. Thefrequency can be continuously swept linearly across any portionof the band with resolution better than 20 Hz and step times as
low as 4 nS. Phase can be similarly controlled within 0.5
degrees. Frequency step size and step time can be changed tofrequency sweep over +/-25 MHz at a rate of 3 kHz and sweep
from 8-20 GHz in 170 mS with minimal frequency error. Atrigger output signal is provided to synchronize other
instruments with the beginning of a sweep. The synthesizer canbe phase locked to a 10MHz reference or optionally configured
for a 100MHz reference, mounted in a single housing with theVDI multiplier chain or provided separately. The synthesizer isprogrammed by sending ASCII text commands over the USB,and open source code for the user interface is also provided inLabview 7.0. Customized solutions are available

Virginia Diodes
www.vadiodes.com

9/5/2017

VDI Synthesizer Data Sheet•

Bandwidth:

8-20GHz, SMA•

Output power:

16dBm min.

•Resolution:<20Hz•

Harmonics:-12dBc•Non-harmonic spurs:<-50dBc in CW mode•

Settling time:

100kHz step settles to <20 Hz within 50uS.

•Sweep rate:>25MHz deviation at 14mS/1GHz, <25MHz at 3uS/1MHz. (Faster rates are possible withfrequency error.) 16-bit control of step time, 4nS minimum.
+/-25MHz peak deviation at 3kHz rate. Smaller deviations are proportionally faster up to ~100kHzmaximum rate. (Faster rates are possible with frequency error.)•Phase step size

< 0.5 degrees.

•CW Switching time:<800uS communication time(incremental) + settling time + sweep time (USB commands can berepeated every 1mS.)•

Frequency stability:

limited by reference oscillator•

Frequency repeatability:

limited by reference oscillator•

Absolute frequency
accuracy:<10Hz + reference oscillator error•

Reference input:

10MHz, 10dBm, SMA, option for 100MHz•

Sweep trigger output:

0-3.3V digital signal, BNC (transitions high at the beginning of the sweep up and low at thebeginning of the sweep down.)•Typical phase noise

See graph on front side of handout•

Interface:

USB control by ASCII text commands to FTDI chip. Open source code provided for Labview 7.0.

•Size:

LxWxH: ~6.125x4.375x1.5” excluding connectors, reference oscillator, fan, and external DC powersupply•

DC Power:+15V ~3A, -15V ~80mA, Separate DC power supply included with AC wall plug, consumes ~50W

Virginia Diodes
www.vadiodes.com

9/5/2017

FM Option
The FM option allows uploading an arbitrary waveform to modulate
phase. The waveform can be played in CW mode or while thesynthesizer output is ramping up and down in frequency.
Software is included which uploads a waveform to produce sinusoidal frequency modulation
and allows the user to specify peak deviation and modulation rate.
An output trigger signal provides an LVTTL (0-3.3V) square wave synchronized with theuploaded waveform.
Specifications:•

16 bit control of phase from 0 – 2pi*n where n is an internal multiplication factor determined by the synthesizer settings. A
typical value for n will be 52.

•

16 bit control of step time in multiples of 4nS. Minimum step time =4nS, maximum step time =262.14uS.

•3dB modulation bandwidth of ~70kHz.

•BNC connector for LVTTL (0-3.3V) output trigger signal.

•Using the supplied software, FM rates between ~3Hz to >200kHz are possible with maximum peak deviations following theformula pi*n*(modulation rate) up to the 3dB bandwidth.

Virginia Diodes
www.vadiodes.com

39/5/2017