At 07:22 AM 7/5/2005, Frank Brickle wrote:
Jim Lux wrote:
Seems that a better way to measure clock accuracy on the sound card is to
generate a sine wave in software and run it out to the (external
reference locked) counter.
The spotting tone function in the DSP will generate a continuous sine, at
an arbitrary frequency, with the CORDIC oscillator function used
everywhere in the system.
There you go, then... Fire up the spotting tone at some convenient
frequency, run the audio output from the Delta 44 into your counter, and
directly measure the clock rate. The ideal frequency would depend on your
type of counter (straight gate or ratiometric, for instance).
James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875
