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I need to implement BPSK modulator and demodulator and I'm having a few issues.
1) Is there a way to trigger DMA channel without use of PWM? It just doesnt let me connect clock directly to triger input.
2) I can't seem to find any substitution for Analog Mixer. Is there a way to implement his function with some other component?
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PSoC 4 Architecture
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kristijan,
I did not implemented BPSK myself, so I can only provide general advise. I looked around and found a variety of approaches. I believe that at 20kHz carrier frequency the P4200 resources are enough to directly sample input signal and to extract quadrature components (I/Q). Some code examples can be found on TI website (code attached, unchecked)
And another code from TI here:
There are some matlab examples on stack exchange like that, which are quite explanatory
digital communications - Simulating BPSK Costas Loop in Matlab - Signal Processing Stack Exchange
/odissey1
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1. What is the carrier frequency?
2. Why not PSoC5?
/odissey1
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Carrier frequency is arround 15-20 kHz.
It wasn't the technology i chose. I got this board to make project with it from my university. It got chosen because it has stable clock frequencies. So I need to implement it with this board.
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Start with sine output project examples from this thread (RAM-DMA-DAC). This will assist you to make a BPSK transmitter. You would likely have to configure two DMA channels (second one with offset of 180 deg) to transmit 0 and 180 phase.
Whether you will be able to implement a BPSK receiver on the same PSoC4, that is the wuesques, due to limited resources.
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I managed to implement transmitter using two descriptors in DMA controlled with software.
Receiver is problematic because of missing analog mixer. Do you have any idea how I might implement it without mixer? Because it seems to me that mixer is essential part. I'm trying to make it coherent but if it's impossible I'm open to noncoherent demodulation.
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kristijan,
I did not implemented BPSK myself, so I can only provide general advise. I looked around and found a variety of approaches. I believe that at 20kHz carrier frequency the P4200 resources are enough to directly sample input signal and to extract quadrature components (I/Q). Some code examples can be found on TI website (code attached, unchecked)
And another code from TI here:
There are some matlab examples on stack exchange like that, which are quite explanatory
digital communications - Simulating BPSK Costas Loop in Matlab - Signal Processing Stack Exchange
/odissey1