Chapter 12 - Digital Keying Techniques Flashcards
1
Q
If the data rate is 64Kbits/s and it is transmitted using PSK and the FSK what is the bandwidth of the signals? (PSK = 128Kbps, FSK = 192 Kbps)
A
PSK = 2 * 64 = 128 Kbps
FSK = 3 * 64 = 192 Kbps
2
Q
Draw 4FSK in the frequency domain. Which M-ary scheme uses two orthogonal signals at the same frequency to generate its output?
A
Quadrature Phase Shift Keying (QPSK)
3
Q
Why is QFSK more power efficient and noise resilient than BFSK?
A
Because it transmits two bits per symbol, allowing for longer dwell times per frequency.
This increased dwell time means more energy per symbol, resulting in better Signal-to-Noise Ratio (SNR) and greater robustness against noise, making QFSK a more reliable choice in noisy environment.
