Matt E. wrote:
Yes, you can change the filter taps in the FPGA. See the halfband (HB)
Thanks! I’ll take a look.
I read on a previous thread that it is possible to invert the spectrum of the sampled signal so that the tuned frequency would be the FM carrier. The end result being a stream from the USRP where 0 Hz is the center frequency of the audio carrier the the video carrier is at 4.5 MHz. Is this possible? The advantage here is that the base-band audio does not need to be shifted before FM demodulation; also the video carrier does not need to be shifted before demodulation (AM).
Not sure what you’re looking for here.
After thinking about it, I’m not sure either. I figured I can to tune to
FM carrier to the center frequency (0Hz), set the decimation to 4 (16
MS) and the video carrier is at -4.5MHz. Unfortunately, my USB/computer
can’t handle can’t handle the 16 MS rate. I was hoping to avoid
translating the signal by placing the FM signal at 0Hz. Since my PC
can’t handle that data rate, I’m just going to concentrate on the NTSC.
As an aside: It would be nice to have something like the GC4014 on-board
the USRP. In my application it could be used to tune the video and audio
signals on separate receiver channels without using up resources on the
PC (and also reduce the need for a faster interface in some cases). Not
sure if there’s enough room on the FPGA though.