The filter that may not be realized by approximation of derivatives techniques are

1) Band pass filters
2) High pass filters
3) Low pass filters
4) Band reject filters

The interface between an analog signal and a digital processor is

A. D/A converter

B. A/D converter

C. Modulator

D. Demodulator

The speech signal is obtained after

A. Analog to digital conversion

B. Digital to analog conversion

C. Modulation

D. Quantization

Telegraph signals are examples of

A. Digital signals

B. Analog signals

C. Impulse signals

D. Pulse train

As compared to the analog systems, the digital processing of signals allow

1) Programmable operations
2) Flexibility in the system design
3) Cheaper systems
4) More reliability

A. 1, 2 and 3 are correct

B. 1 and 2 are correct

C. 1, 2 and 4 are correct

D. All the four are correct

The Nyquist theorem for sampling

1) Relates the conditions in time domain and frequency domain
2) Helps in quantization
3) Limits the bandwidth requirement
4) Gives the spectrum of the signal

A. 1, 2 and 3 are correct

B. 1 and 2 are correct

C. 1 and 3 are correct

D. All the four are correct