What's your sampling rate? The further you go towards the edge of your Nyquist zone, the more the anti-aliasing filter might be kicking in.
Cheers, Martin On 03/17/2016 10:23 AM, tom x wrote: > Hi, > > My setup is a USRP N210 receiving from a transmitter sending a few > packets a second. (The packets are decoded with Bloessl's 802.15.4 PHY > block if it matters) > > Let's say the transmitter is sending data on frequency f_t. > > I set the USRP to receive on f_t plus an offset f_o. > The next block is a frequency xlating FIR filter centered at -f_o. > This is intended to correct the offset. > > I made a slider block for f_o and allowed it to vary between 0 and 3MHz. > I need an offset of a few MHz for my application. However, the number of > packets received seems to drops as I increase f_o. I get almost no > packets after f_o is increased over 0.5MHz. > > The overall purpose of this is to carve two channels out of the received > bandwidth with two frequency xlating FIR filter blocks, with the USRP > tuned between the channels and the filter blocks centered at offsets > that put them on the channel peaks. As explained above, if the offset is > too big, it stops working. Why do you think this is happening? > > Thanks, > Tom > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
