Bill, In general, the DSP source will be in the DttSP project/folder. Search in there for a file called sdr.c. Look for function do_tx_AM(). This has the modulation scheme for AM. This line does the grunt work:
Cmplx(0.5 + 0.5*(CXBreal(tx.buf.i, i) - tx.scl.dc.re),0.0); The first 0.5 is the carrier value and the following 0.5 scales the modulation. Note that these values are scaling floats in the range [-1.0, 1.0]. Let us know if you have any other specific questions. Eric Wachsmann FlexRadio Systems > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > radio.biz] On Behalf Of [EMAIL PROTECTED] > Sent: Tuesday, December 20, 2005 10:04 AM > To: FlexRadio@flex-radio.biz > Subject: [Flexradio] AM code change requests > > I am jumping onto the SDR1000 bandwagon and have two requests: > Being an avid AM operator it would be very useful to > have the following: > > 1--On-screen or programmable alc trip point > > 2--Adjustable reduced carrier AM so that it will be possible to obtain > greater than 100 percent modulation in the upward direction while > maintaining a 25 watt carrier. Currently it appears that given the > asymmetry of the male voice, 100 percent positive only gives about > 75 percent in the negative direction (carrier cutoff). Subsequently it > seems when the 25 watt carrier is modulated as above- the alc > prevents the true asymmetry of the male voice to go through. > > If you could point me to the lines in the source code that control the > above perhaps I could make the changes with your tutoring? > > Thanks > > Bill Nagle > [EMAIL PROTECTED] > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
