Friday, March 17, 2017

Why USB RF Signal Generators Should Be in Your Next Project

Low-cost Universal Serial Bus (USB) radio frequency (RF) signal generators have recently
come on the scene in the wireless world. They promise to be game changers for many
reasons. Until these devices came out, a prospective buyer had two choices when it
came to RF signal generation solutions. The buyer could either purchase a $20K+
benchtop box with all the bells and whistles, or they could purchase a $6K narrowband
“synthesizer”, either hard coded to one frequency, or with an RS-232 programming port
to figure out. Both of these solutions would typically take eight weeks to deliver. They
are generally build-to-order components.
USB RF signal generators are actually a hybrid approach to both of those options
mentioned above—they can be much cheaper and deliver in a couple of days.
A great (made in the USA) example is the Windfreak Technologies SynthHD
Dual Channel Microwave Signal Generator
for $1,279. This price is surprisingly cheaper than some RF test cables.
MSG Microwave Signal Generator


The device has two independent channels that can tune in 0.1 Hz increments from
54 MHz to 13.6 GHz. The SynthHD’s RF power is adjustable in .01 dB increments
from -50 dBm to +22 dBm. It also has many modulation features including FM chirps.
The relative phase between the two channels can be adjusted in .01 degree increments.
It is a hybrid approach because the device can either be controlled
with a PC graphical user interface (GUI) like benchtop test and measurement (T&M)
equipment, or it can be programmed to function as a module inside a communication
system without a PC, like the narrow band synthesizer mentioned above.
The SynthHD signal generator will generate sweeps. The sweeps can be single
channel or dual channel. The device can sweep up or sweep down. It can also ramp
up or down amplitude while sweeping. The sweep can be controlled with an external
trigger to either perform a full sweep per trigger, or perform a single step. In dual
channel mode you can program a constant frequency offset between
the two channels for the sweep.
The SynthHD signal generator will generate hops. The GUI allows the user to program
up to 100 arbitrary points with a frequency and amplitude in dBm. This table is stored
onboard in nonvolatile memory. Like the sweep mode the user can then have an offset
on the other RF channel, hop up the list, hop down the list, and work with the trigger input.
Additionally, the SynthHD signal generator will digitally modulate FM, AM, and pulse.
FM can be a typical sinusoidal signal, or it can also be a chirp. AM can also be the t
ypical sinusoid signal or it can be ramps. The modulations can be combined. Combining
a pulse and a chirp allows the user to set up a frequency modulated continuous wave
(FMCW) radar signal. You can even combine this with the sweep function. As an
electronic warfare example, you could sweep a pulsed waveform across a range
of frequencies. Rates can be very slow, or in the case of FM, up to 5 KHz. Of course,
all of these features can be saved to the device; it will begin sweeping on power up
without a PC connected!
Use the external Trigger connection to perform external modulation such as
FM, AM and Pulse. More details here!!!!

SynthHD and SynthHD Pro Software GUI


No comments: