Question

The signal to quantization noise ratio of an analog to digital converter having full scale range of ±1 volt for seven bit word length is 42dB. The approximate value of signal to quantization noise ratio for 9 bit word length is

• A. 44 dB
• B. 24 dB
• C. 54 dB
• D. 75 dB

Hint:

For each additional bit in an Analog-to-Digital converter the signal to quantization noise increases by approximately 6 dB.

Answer 1

The Correct Option is C

The signal-to-quantization-noise ratio (SQNR) in decibels increases by approximately 6 dB for every additional bit in the ADC. If SQNR is 42 dB for 7 bits, for 9 bit it will increase by 2 bits. Increase in the SQNR is: \[ 2 \times 6 = 12 dB \] Therefore new SQNR will be: \[ 42+12 = 54 dB \]