RE: [soft_radio] Re: AM demod from I/Q in hardware

[Ray Anderson]

How about envelope detecting both the I and Q signal independently (perhaps with a simple diode and RC filter) and them summing the resulting audio signals? Perhaps not an optimal solution, but it should work.   Or you could emulate what Alberto does in the SDRadio ECCS demodulator where you could have a pair of SSB demods (one for LSB and one for USB) fed from the IQ channels. Then sum the audio outputs from the demods. The gotcha’ on that approach is that you need to assure that you are always in zero beat unless you don’t mind annoying heterodyne whistles in your audio. This would require some sort of feedback to form a frequency control loop……     -Ray     WB6TPU   From: soft_radio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Alberto I2PHD Sent: Thursday, August 25, 2005 9:29 AM To: soft_radio@yahoogroups.com Subject: [soft_radio] Re: AM demod from I/Q in hardware   Chris,   I can't help you here... I haven't the faintest idea on how to compute sqrt(I^2 + Q^2) in hardware, apart from using a look-up table programmed in a ROM... maybe someone else will stand up and suggest a simpler way. 73  Alberto  I2PHD --------------------------------------- Chris Hirt wrote: Hi all Perhaps my question is stupid, but I am momentary at the end of my ideas. What the heck is the demodulation of AM if I have a I/Q signal ? My homebrew HDR-2005 (= HardwareDefinedRadio 2005 ;-) is a mixture between QRP2001, SDR-1000 and other concepts. It sounds great in SSB. I demodulate LSB, USB or both but not AM. Yes, yes I know M = srt(I^2 + Q^2), but how I do it in hardware ! Up to now all my trials with AM ended in much distortion. Does anybody knows how I produce a clear AM from I and Q with (analog) hardware? Best regards Chris . SPONSORED LINKS Craft hobby Hobby and craft supply Ham radio Hobby supply Ham radio sales YAHOO! GROUPS LINKS  Visit your group "soft_radio" on the web.    To unsubscribe from this group, send an email to:  [EMAIL PROTECTED]    Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.