[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] Simple WBFM Transmitter - How to configure the US
Re: [Discuss-gnuradio] Simple WBFM Transmitter - How to configure the USRP1 block to transmit ?
Thu, 1 Aug 2013 10:34:21 -0400
On Tue, Jul 30, 2013 at 10:35 PM, Bruno Cardoso <address@hidden> wrote:
> Hi Tom,
> I tried to follow your tips but the FM transmitter is not working yet. Here
> is the file: WBFM_transmitter_Bruno2.grc
> I'm matching the sample rates all the way through my flowgraph.
> I'm also using the USRP1 through the ¨UHD: USRP Sink¨ block with a 250k
> sample rate, which is a rate that's supported both by N2XX family and
> USRP1/B100 family.
> There is something missing yet.
> Thanks for your help.
1. You don't need a throttle block. A throttle is only necessary when
running without any hardware. You have both an audio sink (running at
44.1 kHz) and a USRP sink (running at 250 kHz). These are your
rate-limiting blocks and the throttle is just getting in the way.
2. You are massively overloading the signal into the USRP sink. That
signal level should be +/- 1 at the very most. But you'll want to back
off from that for linearity reasons. Instead of setting the gain of
the LPF to 40, create a slider for that that goes from 0 - 1 with 100
steps. Default it to 0.5. The signal looked very clean that way.
Visit us at GRCon13 Oct. 1 - 4
- Re: [Discuss-gnuradio] Simple WBFM Transmitter - How to configure the USRP1 block to transmit ?,
Tom Rondeau <=