Jim, I agree, but we are talking about a test. The test signal would have to have a signal that either sweeps or is shifted in frequency. This would be a test like a two tone test. A two tone test is not a real world test, but it is made with very specific signals and the results are well known. I think we would have to approach group delay the same way.
Through equalization most transmitter/receiver anomalies can be corrected. Non-linear effects of the analog circuits cannot be necessarily corrected, but the signals can be designed to reduce their effects. MT63 is a good example. 64 tones that can be run into an amateur radio at full power with third order IM products that are 23 dB down, and not cause excessive bandwidth outside of the necessary bandwidth. I have some spectrum analyzer plots of this, but cannot find them right now, and my spectrum analyzer is in the field. As soon as I get it back I will make some tests. Even PSK31 run at full power really does not cause the IM problems that most people claim. Most of the IM problems happen in the receiver, or in over driven analog sound card and transmitter audio circuits. 73, Mark N5RFX >While they may be sinusoids, they are not steady state. The tones >are switched and their phase may change depending on the modulation. >An example would be the first cycle of a sinusoid applied to >capacitor or an inductor. You will get some distortion. How much >is the question. Phase changes also require a high slew rate >capability in order to not be distorted. Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
