Henry, I see no problem here.
You have a voltage plot. It shows approx 2.0 V @ 500 Hz, 1.0 V @ 1000 Hz, and 0.5 V @ 2000 Hz In voltage terms - twice [or half] the voltage change does represent 6 dB - so - your circuit is working fine and would graph as a straight line [with the expected slope] if you changed the Y axis to dB. nj --------------------------------------------------------------- --- In [email protected], Henry Wingate <[EMAIL PROTECTED]> wrote: " I just finished a remote receiver project where I had to de-emph using an RC circuit. I have always heard that the rule of thumb is: 75 us for wide band broadcast audio and 750 us for narrow band. I used a 3.3k resistor and a 0.22uf cap. 726us - close enough. It sounded pretty good, so I thought, what the heck, I'll sweep it (it was raining). Big mistake. Now I don't understand why it sounds so good. Click here for the plot: http://webpages.charter.net/k4hal/de_emp.pdf Not anywhere near 6db per octave. ..."
