Digital Signal Processing

Design of Optimum Equi Ripple Linear Phase FIR Filters

Question 1
Marks : +2 | -2
Pass Ratio : 100%
If M is the length of the filter, then at how many number of points, the error function is computed?
2M
4M
8M
16M
Explanation:
Having the solution for P(ω), we can now compute the error function E(ω) from
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The filter designs which are formulated using chebyshev approximating problem have ripples in?
Pass band
Stop band
Pass & Stop band
Restart band
Explanation:
The chebyshev approximation problem is viewed as an optimum design criterion on the sense that the weighted approximation error between the desired frequency response and the actual frequency response is spread evenly across the pass band and evenly across the stop band of the filter minimizing the maximum error. The resulting filter designs have ripples in both pass band and stop band.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
If δ1 represents the ripple in the pass band for a chebyshev filter, then which of the following conditions is true?
1-δ1 ≤ Hr(ω) ≤ 1+δ1; |ω|≤ωP
1+δ1 ≤ Hr(ω) ≤ 1-δ1; |ω|≥ωP
1+δ1 ≤ Hr(ω) ≤ 1-δ1; |ω|≤ωP
1-δ1 ≤ Hr(ω) ≤ 1+δ1; |ω|≥ωP
Explanation:
Let us consider the design of a low pass filter with the pass band edge frequency ωP and the ripple in the pass band is δ1, then from the general specifications of the chebyshev filter, in the pass band the filter frequency response should satisfy the condition
Question 4
Marks : +2 | -2
Pass Ratio : 100%
If the filter has symmetric unit sample response with M odd, then what is the value of Q(ω)?
cos(ω/2)
sin(ω/2)
1
sinω
Explanation:
If the filter has a symmetric unit sample response, then we know that
Question 5
Marks : +2 | -2
Pass Ratio : 100%
If the filter has anti-symmetric unit sample response with M even, then what is the value of Q(ω)?
cos(ω/2)
sin(ω/2)
1
sinω
Explanation:
If the filter has a anti-symmetric unit sample response, then we know that
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Which of the following defines the weighted approximation error?
W(ω)[Hdr(ω)+Hr(ω)]
W(ω)[Hdr(ω)-Hr(ω)]
W(ω)[Hr(ω)-Hdr(ω)]
None of the mentioned
Explanation:
The weighted approximation error is defined as E(ω) which is given as
Question 7
Marks : +2 | -2
Pass Ratio : 100%
If the filter has anti-symmetric unit sample response with M odd, then what is the value of Q(ω)?
cos(ω/2)
sin(ω/2)
1
sinω
Explanation:
If the filter has a anti-symmetric unit sample response, then we know that
Question 8
Marks : +2 | -2
Pass Ratio : 100%
In Parks-McClellan program, an array of maximum size 10 that specifies the weight function in each band is denoted by?
WTX
FX
EDGE
None of the mentioned
Explanation:
FX denotes an array of maximum size 10 that specifies the weight function in each band.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
The filter designs that contain more than L+2 alternations are called as ______________
Extra ripple filters
Maximal ripple filters
Equi ripple filters
None of the mentioned
Explanation:
In general, the filter designs that contain more than L+2 alternations or ripples are called as Extra ripple filters.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
If δ2 represents the ripple in the stop band for a chebyshev filter, then which of the following conditions is true?
1-δ2 ≤ Hr(ω) ≤ 1+δ2;|ω|≤ωs
1+δ2 ≤ Hr(ω) ≤ 1-δ2;|ω|≥ωs
δ2 ≤ Hr(ω) ≤ δ2;|ω|≤ωs
-δ2 ≤ Hr(ω) ≤ δ2;|ω|≥ωs
Explanation:
Let us consider the design of a low pass filter with the stop band edge frequency ωs and the ripple in the stop band is δ2, then from the general specifications of the chebyshev filter, in the stop band the filter frequency response should satisfy the condition