Hello. We are making some sdr thing. So there is a need to catch carrier frequency for down shifting. We know nothing about baseband signal, except may be that it was digital or analogue modulated. Could anyone suggest any method? We're computing everything with modern pc, so there is no problem with arg(), log10(), sin()/cos(), square or square root and so on. Thank you in advance
Need omnivorous carrier recovery method
Started by ●July 20, 2010
Reply by ●July 20, 20102010-07-20
On Jul 20, 7:15�am, "mtr" <baranov.mv@n_o_s_p_a_m.gmail.com> wrote:> Hello. We are making some sdr thing. So there is a need to catch carrier > frequency for down shifting. We know nothing about baseband signal, except > may be that it was digital or analogue modulated. Could anyone suggest any > method? > We're computing everything with modern pc, so there is no problem with > arg(), log10(), sin()/cos(), �square or square root and so on. > > Thank you in advanceThere is no universal technique for carrier recovery that works across all analog and digital modulations. You're not going to be able to make an "SDR thing" without knowledge of what it's going to receive. An AM receiver is different from an FSK receiver, which is different from an OFDM receiver. The allure of a software-defined receiver is that it can easily be reconfigured to receive different modulation formats, not necessarily that it is a universal receiver that can handle all combinations at once. Jason
Reply by ●July 20, 20102010-07-20
Ok, it's obvious that it's not always possible to get carrier for any modulation type using the same way. But we want to code as fewer different methods as possible. Is there some method for any digital angular modulation (M-fsk, M-ask, M-psk and qam)?
Reply by ●July 20, 20102010-07-20
On Jul 20, 9:03�am, "mtr" <baranov.mv@n_o_s_p_a_m.gmail.com> wrote:> Ok, it's obvious that it's not always possible to get carrier for any > modulation type using the same way. But we want to code as fewer different > methods as possible. Is there some method for any digital angular > modulation (M-fsk, M-ask, M-psk and qam)?No. Jason
Reply by ●July 20, 20102010-07-20
> > > Ok, it's obvious that it's not always possible to get carrier for any > > modulation type using the same way. But we want to code as fewer different > > methods as possible. Is there some method for any digital angular > > modulation (M-fsk, M-ask, M-psk and qam)? >http://en.wikipedia.org/wiki/Costas_loop Mark
Reply by ●July 20, 20102010-07-20
Hello Baranov The most universal and dumb method is not doing any carrier recovery. Receive your signal incoherently. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com mtr wrote:> Hello. We are making some sdr thing. So there is a need to catch carrier > frequency for down shifting. We know nothing about baseband signal, except > may be that it was digital or analogue modulated. Could anyone suggest any > method? > We're computing everything with modern pc, so there is no problem with > arg(), log10(), sin()/cos(), square or square root and so on. > > Thank you in advance > >
Reply by ●July 20, 20102010-07-20
On 7/20/2010 7:15 AM, mtr wrote:> Hello. We are making some sdr thing. So there is a need to catch carrier > frequency for down shifting. We know nothing about baseband signal, except > may be that it was digital or analogue modulated. Could anyone suggest any > method? > We're computing everything with modern pc, so there is no problem with > arg(), log10(), sin()/cos(), square or square root and so on. > > Thank you in advanceA PC? What is your sampling rate? How much sampling jitter is there? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●July 20, 20102010-07-20
Reply by ●July 20, 20102010-07-20
On Jul 20, 7:15�am, "mtr" <baranov.mv@n_o_s_p_a_m.gmail.com> wrote:> Hello. We are making some sdr thing. So there is a need to catch carrier > frequency for down shifting. We know nothing about baseband signal, except > may be that it was digital or analogue modulated. Could anyone suggest any > method? > We're computing everything with modern pc, so there is no problem with > arg(), log10(), sin()/cos(), �square or square root and so on. > > Thank you in advanceThe most universal method is to provide a tuning knob and a constellation display.
Reply by ●July 20, 20102010-07-20
