I have written Matlab script for BPSK modulation. The way my code works is as follow:

series of 0 and 1----> NRZ data (continuous rectangular pulses with amplitude -1 and 1)--->multiply by carrier----> add noise--> multiply by carrier---> integration--->detection---> Bit Error collection?

I would like to know can anyone tell me where I should apply DAC and ADC ? I am wondering should it be after NRZ data or before that for DAC ? :!:

  • $\begingroup$ If you want to simulate the noise impact, why you want/need to apply the ADC DAC? Do you plan to simulate specific behavior (noise impact) of these devices? Why not factor their noise impact the noise you add "after" the carrier? $\endgroup$ – Moti Jul 11 '15 at 3:49
  • $\begingroup$ I am not quit sure what you mean.this is simple case and I will have continuous channel later on so I need to use continuous pulses not discrete.therefore noise should be added to continuous signal and I would like to know where to add DAC and ADC in the process of modulation? $\endgroup$ – user59419 Jul 11 '15 at 4:01
  • $\begingroup$ You could use direct modulation with DAC (rate some what higher than the carrier frequency) and than direct down conversion with the ADC. You need to understand how you plan to use your DAC and ADC in the simulation and what you attempt to simulate - for example, are you interested in quantization noise impact? The jitter in the ADC? $\endgroup$ – Moti Jul 11 '15 at 4:15
  • $\begingroup$ I want to use my own modulation and demodulation technique in Matlab I only need to use ADC or DAC for conversion to analog or digital signal. I am not interested in quantization noise impact. I am only interested in knowing where to apply the ADC or DAC? $\endgroup$ – user59419 Jul 11 '15 at 5:12
  • $\begingroup$ It really depends on the nature of the modulation. It could be just an On/Off for modulation of the carrier(s) - switching, and high speed ADC for direct conversion for the demodulation or down convert to baseband and then use a low rate ADC. $\endgroup$ – Moti Jul 12 '15 at 5:16

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