This data is from my Soft Rock V7 beta board built using an OPA2228 op amp. I also changed the phase shift capacitor (C9) to 8pf to get good IQ phase relationship - this is probably due to added stray capacitance from the .100 header I've mounted to allow me to easily change the phase shift cap..
MDS was measured as -109 dbm with an Extigy and -112 dbm with a Delta 44 sound card. . The specturm display does show some minor spurs, particularly with the Extigy which shows a hump at 0, and +/- 5khz
Some other measrements:
Input current: 29 ma@ 13.8 V supply
Max input signal without distortion on IQ output: -16 dbm (measured for an input signal @ 28.064 MHz)
Oscillator Frequency: 28.052 MHz
Comments to: Bill Tracey (kd5tfd@ewjt.com)
Last Updated 1 Arpil 2006 Copyright © 1 April 2006