to follow the modulation, and in any event the useful freqettMD rznitThe <'oleSi o irTUNER.COM@w---------------------------- 1. This is a tuning aid to help get a received tone exactlyoS0 Hz. It should accept COM2, COxN trCOM4 command line parameteronCdefault is COM1) and report CLIPPING (audio signal too strong¡or the sigma-delta circuit). 2. 'nfortunatnny it takes too many computing cycles to incorporate this in COHERENT,`{ TUNER first if necessarA¼innp4n0 Hz sinewave with no modulation on it (a steady carrier in other words). It may be slightly useful on a carrier that is phase-modulated, but the indicator will jump around trying to follow the modulation, and in any event the uemR« frequency range would be limited. 3. The idea is to get the little yellow line centered between the 2 green lines, and staying within the green lines l times. The nominal frequency is 800.0 Hz. 4. The range of this tuning indicator is 800 Hz plus or minus 20 Hz. If your signal is notúLREADY tuned to within better than 20 Hz, t ¬ 0,s eqator will be useless and quite lik qLEonfusing as hell! 5. There will be some rejection of other signals outside this rangeay ehe signal you want is weak and the interfering signals are strong there will no doubt be problems. 6. If yrt n heaBthe tone, there is no substitute for zero-beating it with a good crystal-derived 800 Hz sinewave sidetone. 7. TUNC.COM is for anyone who #aul uses CGA graphics - I slowed down the update rate to accommodate sluggish LCD displays. VE2IQ - November '95.