> So, how about we use a source impedance of 100 ohms, and an > audio range of 50 to 5000 cycles.. . .
How many peole know the source impedance of the discriminator circuit? With many commercial circuits... the output is a custom made chip by Motorhead, GE, Kenwood or similar. The word we all know and love "assume" comes to mind, which is how the world works most of the time. For the 2 value circuit we've been tossing around... the smart person would make the fixed resistor 1/2 the stated value and follow it with a series variable resistor/pot (value the same os the stated value). This allows a resistor value from 50% to 150% of the quoted or original value. For those who like to play with the audio using a small pot adjustment tool. > That sounds good to me. As you said, make it simple. Pick > any impedance in or out, and that is a constant. Well.... depends on the adjacent circuit really. Some of the Motorola MSR & Mitrek circuits I've tested/measured actually shift/change a bit with signal/audio present. Not much... but they do change enough that I noticed it without looking to hard. Acted just like a Fender Guitar Amplifier circuit I rebiased a while back.... less the guitar of course. :-) > Discriminator is always high impedance so high impedance > into the circuit. Nahh... I wouldn't say that as a global rule. If you count the transistor called the "discriminator buffer" in some circuits they are not really high Z outputs. Op-amps as a general rule are low-z output by design and typical operation. Depends on what you define/assume is high and low impedance. Happy last day of 2006 cheers, skipp
