DDS Signal Generator

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.

When installed inside a GPS10RBN frequency standard, the programming is accomplished via the front panel keyboard. 

The 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 10230000.000010.

The frequency can also be programmed via the GPS10RBN's RS232 interface.

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. 

The SG1640 is a DDS signal generator with a frequency range from 0 to 1640 MHz in 10 µHz steps.

The FSG series are portable, handheld signal generators covering 20 MHz to > 3 GHz in various instruments.