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From: | Marcus Müller |
Subject: | Re: [Discuss-gnuradio] Find and look to center frequency and phase of bandwidth with help of stored original version of that |
Date: | Sun, 20 Aug 2017 20:12:36 +0200 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
Dear Mohammad, Is the 1 MHz carrier modulated? If yes, what is its bandwidth?
Are the two signals correlated? I'm pretty sure that *if* you go the LMS / adaptive route, then there will be no way around synchronization. I'm *not* sure that it's the optimal route to take! Best regards, Marcus On 20.08.2017 18:11, mohammad nejati
wrote:
Hi , It is difficult to explain what i need but i want to try it . I have a single modulated carrier with 5 Mhz bandwidth i send it throw cable and receive delayed version of that with a good SNR like 45dB . I store i/q sample in last stage of transmitter , In cable i add one 1 Mhz carrier with lower power into exactly 5 mhz equipped bandwidth of carrier (1Mhz carrier is hidden in 5 Mhz carrier due to lower signal power) . what i want to do is in receiver subtract transited signal from received signal in a proper delay and phase and recover 1 Mhz carrier . I use LMS algorithm for adaption and subtraction and that work only when received i/q sample have exactly same center frequency with stored transmitted i/q sample which in reality with SDR board and zero if architecture it is almost impossible . i don't want find center frequency of received carrier with method like costas loop , because modulated signal may have difference modulation like 64 QAM , 16 QAM , 32APSK , BPSK ... i want find and lock received center frequency and phase with help of that i stored a correct version of that before transmit . i attached an image of subtracted signal and recovered smaller carrier (which is in an ideal condition without frequency drift). Thank you , |
smime.p7s
Description: S/MIME Cryptographic Signature
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