Topic: Digital Communications
A 12-bit ADC has input signal range of ± 1 V. The signal to quantization noise ratio if a sine wave signal with 0.25 V peak voltage is given as input is:
- A. 61.8 dB
- B. 72 dB
- C. 74 dB
- D. 48 dB
Answer: A. 61.8 dB
Explanation: For n = 12 bits, range is -1 V to 1 V (4096 levels). With a peak voltage of 0.25 V, only 1024 levels are utilized, corresponding to effective bits n' = 10. Signal to quantization noise ratio = 1.8 + 6 * n' = 1.8 + 60 = 61.8 dB.