H64DSP MCQ Sample Questions

Laplace transform is used predominantly for analysis of
-> continuous signals and analogue systems

This is an example of a Fourier transform

  • DFT
  • FFT
  • Fourier series
  •  Fourier integral

This filter passes low frequencies
-> a Low pass filter

Averaging

  • is applicable to an ensemble of records only
  • reduces noise for any signal
  • requires signals in every record to be coherent
  • reduces the power of the noise by the number of records

The fastest ADC technology is
-> Flash ADC

Aliasing

  • can be reduced by increasing the sampling frequency
  • can be reduced by preliminary low pass filtering means
  • can be reduced by using oversampling
  • distorts the digitised signal

DFT stands for
-> Discrete Fourier Transform

OFDM

  • utilises DFT for communications purposes
  • combines sinewaves at orthogonal frequencies
  • transmits one bit at a time
  • employs guard time to allow for multi path propagation
  • uses cyclic prefix to reduce influence of transitions

Digital Hilbert transformer is implemented by
-> an FIR digital filter with asymmetric impulse response

An FIR digital filter

  • could be unstable
  • could process signals without any phase distortions
  • has zeroes on the z-plane
  • is conventionally characterised by its coefficients
  • is a linear device

The coefficients of an FIR adaptive filter are adjusted according to
-> current error, design parameter μ, present input samples

An adaptive filter

  • could predict future samples of a sequence
  • is a linear device
  • is a time invariant device
  • minimises the difference between the desired and actual outputs
  • requires an extra signal input to function