Hello Time Nuts, I'm going to try a two antenna approach - parts are on order.
Buying a 2nd board vs. trying to implement a low-noise amplifier is a wash for the cost for the 2nd audio board. It will require a few board mods - but they are simple. When I have some interesting results, I will publish them to the group. Yes, good if not great thread here - have enjoyed the discussion and hope to see some good results. 73's, John AJ6BC On Sun, Oct 25, 2020 at 11:40 AM Andy Talbot <[email protected]> wrote: > That doesn't appear to give you 1/4 the base sampling rate as you suggest > with "... to sample at 4 times the desired rate..." > I do something similar on a 1kHz tone, generating I/Q at 1kHz sampling rate > on a bandwidth up to 500Hz, ie 750 - 1250Hz > Samples at 4kHz are S1, S2, S3, S4 > Then I = S1 + S2 - S3 - S4 > Q = S1 - S2 - S3 + S4 at 1kHz sampling, centred on 1kHz tone > > > See http://g4jnt.com/Coherent_LF_Receiver.pdf where the technique is used > in a coherent LF receiver. > > Andy > www.g4jnt.com > > > > On Sun, 25 Oct 2020 at 02:17, jimlux <[email protected]> wrote: > > > On 10/24/20 3:53 PM, paul swed wrote: > > > > > > The classic way to get I/Q is to sample at 4 times the desired rate, > > then, given that your input samples are x(1),x(2),x(3),x(4), etc. the > > I/Q streams are > > > > I(1) = X(1) > > Q(1) = X(2) > > I(2) = -X(3) > > Q(2) = -X(4) > > I(3) = X(5) > > Q(3) = X(6) > > I(4) = -X(7) > > Q(4) = -X(8) > > > > and so forth. > > > > This will put your signal right in the middle of the sampling bandwidth. > > > > > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > Virus-free. > www.avg.com > < > http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
