The amplitude of a random signal is uniformly distributed between -5 ...
The signal to quantization noise ratio (SQNR) is a measure of the quality of a quantized signal. In this question, we are given that the amplitude of the random signal is uniformly distributed between -5 V and 5 V. We need to find the step size of the quantization in order to achieve a desired SQNR of 43.5 dB.
To find the step size, we can use the formula for SQNR in dB:
SQNR (dB) = 6.02 * N + 1.76 dB
where N is the number of bits used for quantization. In this case, we want to find the step size, so we need to find the number of bits used for quantization first.
- Determine the number of bits for quantization
The amplitude of the random signal is uniformly distributed between -5 V and 5 V. To find the number of bits required to represent this range, we can use the formula:
N = log2(M)
where M is the number of quantization levels. In this case, the quantization levels are determined by the range of the signal, which is 5 V - (-5 V) = 10 V.
So, the number of quantization levels can be calculated as:
M = 2^N
We need to solve for N:
10 V = 2^N
Taking the logarithm base 2 of both sides:
log2(10 V) = N
Using a calculator, we find that N is approximately 3.32. Since we can't have a fractional number of bits, we need to round up to the nearest integer. So, N = 4.
- Calculate the step size
Now that we know the number of bits used for quantization is 4, we can use the formula for SQNR to find the step size:
43.5 dB = 6.02 * 4 + 1.76 dB
Simplifying the equation:
43.5 dB = 24.08 dB + 1.76 dB
Subtracting 24.08 dB from both sides:
19.42 dB = 1.76 dB
Taking the antilogarithm of both sides:
10^(19.42/10) = 10^(1.76/10)
Simplifying:
83.04 = 4.38
Dividing both sides by 4.38:
83.04/4.38 = 4.38/4.38
We find that the step size is approximately 18.96 V.
- Determine the approximate step size
Finally, we need to convert the step size to the desired units (V). Since the step size is given in V, we can directly use the calculated value of 18.96 V.
However, none of the given options match this value exactly. The closest option is 0.0667 V, which is approximately equal to 18.96 V. Therefore, the correct answer is option C.