ustinoff
Member level 2
Hi everyone.
I try to implement BPSK modulator on FPGA. So, i have binary data stream [1 -1], and modulate carrier frequancy in DAC - that's OK. Now i want to shift my carrier frequancy.
Easy way: cos((w0+w1)t) = cos(w0*t)cos(w1*t) - sin(w0*t)sin(w1*t) (see the picture).
Carrier: something about 70-150 MHz
Data stream: 0,5 - 10 MHz
Shift freq. (in eq. it is w1) around 5-100 kHz (it's w1 in eq)
In sheme with carrier shift i don't convert data stream from [0 1] to [1 -1] sequancy and use [0 1] seq. for control MUXs.
Can this relationship be a reason of uncorrect demodulation (few bits of binary data stream can change by one period of shift freq. => few phase shifts by one period of shift freq.)?
I try to implement BPSK modulator on FPGA. So, i have binary data stream [1 -1], and modulate carrier frequancy in DAC - that's OK. Now i want to shift my carrier frequancy.
Easy way: cos((w0+w1)t) = cos(w0*t)cos(w1*t) - sin(w0*t)sin(w1*t) (see the picture).
Carrier: something about 70-150 MHz
Data stream: 0,5 - 10 MHz
Shift freq. (in eq. it is w1) around 5-100 kHz (it's w1 in eq)
In sheme with carrier shift i don't convert data stream from [0 1] to [1 -1] sequancy and use [0 1] seq. for control MUXs.
Can this relationship be a reason of uncorrect demodulation (few bits of binary data stream can change by one period of shift freq. => few phase shifts by one period of shift freq.)?
