Synchronous detection of signal and conversion of analog into digital signal

Synchronous detection means

a.) Extracting week signal from noise
b.) Need a reference signal with predetermined frequency and phase
c.) a) and b) both
d.) none of the above

Correct Answer: c.) a) and b) both

Explanation:

Synchronous detection means demodulation of received signal and extracting information from it. It requires a reference signal at the receivers with predetermined frequency and phase which is generated using extra circuitry. Synchronous detection helps in extracting weak signals from noise.

Analog signal may be converted into digital signal by

a.) Sampling
b.) Amplitude modulation
c.) Filtering
d.) Mixing

Correct Answer: a.) Sampling

Explanation:

Conversion of analog signal into digital signal converts a continuous time signal in the form of digits. The conversion is done with the help of sampling technique. A sample is a set of values at a point in time space. The average number of samples obtained in one second is known as sampling frequency.