Test Systems manufacture the GPS10RBN frequency
standard. Option 05 for the GPS10RBN is a DDS
This option is now
available as a stand alone module. This page
details more specifications on this product.
The DDS Generator is a direct digital synthesis module.
It accepts a 10 MHz reference (supplied by the GPS10RBN
when supplied as option 05). Internal circuitry
multiplies the 10 MHz to 200 MHz which is the clock
frequency of the DDS IC.
The output can be programmed for any frequency from 0 to
80 MHz (usable to 90 MHz). The step size is 1 µHz.
There are two outputs, a sinewave at about 5 dBm into 50
ohms and a squarewave that drives 1 V into 50 ohms or 0
to 3V into an open circuit.
installed inside a GPS10RBN frequency standard, the
programming is accomplished via the front panel
frequency is entered in Hz. So to program 10.23
MHz the user would enter 10230000 and press Enter. To
add 10 µHz to this value the user would enter
The frequency can also be programmed via the GPS10RBN's
For the stand-alone module, programming is accomplished
via a RS232 interface using a simple Windows program
which is supplied free of charge with the module.
The output frequency accuracy is exactly related to the
10 MHz reference input.
The sinewave harmonics are typically -40 dBc with
harmonics being -20 dBc. Phase noise is typically
-95 dBc/Hz @ 1 Hz, -120 dBc/Hz @ 10 kHz with a
-140 dBc/Hz noise floor.
Allan Variance is < 3 E-11 (tau = 1 second), 1E-11
(tau = 10 seconds) and < 2 E-12 (tau = 100 seconds).
Precision Test Systems also manufactures other DDS and
normal signal generators.
is a DDS signal generator with a frequency range from 0
to 1640 MHz in 10 µHz steps.
FSG series are
portable, handheld signal generators covering 20 MHz to
> 3 GHz in various instruments.