Good voice reproduction via PCM can be achieved with 128 quantization levels. a-How many bits to code a voice signal? b- According to the sampling theorem, samples should be taken at a rate of 8000 samples per second. Determine the data rate for the PCM-encoded digital data. Exercise# 2 What SNR ratio is required to achieve a Bandwidth efficiency of 1.0 for QPSK? Assume that the required bit error rate is 10. Note that SNR= Eb R X , where is the Bandwidth efficiency. Probability of bit error (BER) 1.0 10-1 10-2 10-3 10- 10-5 10-6 NRZ, biphase PSK, QPSK AMI, pseudotemary, ASK, FSK 3 dB 10-7 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (E No) (dB) Figure: Theoretical Bit Error Rate (BER) for various encoding scheme