I have an FIR filter equation, which is y(n) = 0.5x(n) + 0.5x(n - 2). I have to draw the magnitude of the frequency response of this filter? Does anyone know how to do this? thanks in advance for any help
Calculating frequency response magnitude of filter
Started by ●June 4, 2009
Reply by ●June 4, 20092009-06-04
On Jun 4, 9:13�am, "briwel" <briwe...@hotmail.co.uk> wrote:> I have an FIR filter equation, which is > y(n) = 0.5x(n) + 0.5x(n - 2). > > I have to draw the magnitude of the frequency response of this filter? > Does anyone know how to do this? > > thanks in advance for any help1st find the impulse response of your filter (trivial in this case) 2nd find the fourier transform of the impulse response. (quite simple in this case) 3rd find the magnitude of the fourier transform found in step 2. We don't mind giving hints on homework problems but please identify that you are doing a homework problem. Clay
Reply by ●June 4, 20092009-06-04
On Jun 4, 9:13�am, "briwel" <briwe...@hotmail.co.uk> wrote:> I have an FIR filter equation, which is > y(n) = 0.5x(n) + 0.5x(n - 2). > > I have to draw the magnitude of the frequency response of this filter? > Does anyone know how to do this? > > thanks in advance for any helpYou might also try to compute it analytically. It is pretty trivial to do, and you might find the result enlightening. Dirk
Reply by ●June 4, 20092009-06-04
Cheers Clay, I am currently revising for a DSP exam, so this isn't assessed homework but more of a practice question so I can get the technique right. 1. So the impulse respone is 0.5*DELTA(n) + 0.5*DELA(n - 2) 2. I then need to take the FT of that, which is: INTEGRALOF((0.5*DELTA(n) + 0.5*DELA(n - 2))* e^(i*2*pi*f*n)) However, I'm not sure how to take the integral of a delta function, can anyone give me some advice? Thanks alot>On Jun 4, 9:13=A0am, "briwel" <briwe...@hotmail.co.uk> wrote: >> I have an FIR filter equation, which is >> y(n) =3D 0.5x(n) + 0.5x(n - 2). >> >> I have to draw the magnitude of the frequency response of this filter? >> Does anyone know how to do this? >> >> thanks in advance for any help > >1st find the impulse response of your filter (trivial in this case) >2nd find the fourier transform of the impulse response. (quite simple >in this case) >3rd find the magnitude of the fourier transform found in step 2. > >We don't mind giving hints on homework problems but please identify >that you are doing a homework problem. > >Clay > > > > >
Reply by ●June 4, 20092009-06-04
On Jun 4, 2:21�pm, "briwel" <briwe...@hotmail.co.uk> wrote:> Cheers Clay, > > I am currently revising for a DSP exam, so this isn't assessed homework > but more of a practice question so I can get the technique right. > > 1. So the impulse respone is 0.5*DELTA(n) + 0.5*DELA(n - 2) > 2. I then need to take the FT of that, which is: > > INTEGRALOF((0.5*DELTA(n) + 0.5*DELA(n - 2))* e^(i*2*pi*f*n)) > > However, I'm not sure how to take the integral of a delta function, can > anyone give me some advice? > > Thanks alot > > > > >On Jun 4, 9:13=A0am, "briwel" <briwe...@hotmail.co.uk> wrote: > >> I have an FIR filter equation, which is > >> y(n) =3D 0.5x(n) + 0.5x(n - 2). > > >> I have to draw the magnitude of the frequency response of this filter? > >> Does anyone know how to do this? > > >> thanks in advance for any help > > >1st find the impulse response of your filter (trivial in this case) > >2nd find the fourier transform of the impulse response. (quite simple > >in this case) > >3rd find the magnitude of the fourier transform found �in step 2. > > >We don't mind giving hints on homework problems but please identify > >that you are doing a homework problem. > > >Clay- Hide quoted text - > > - Show quoted text -Do an infinite sum, it only has 2 non-zero terms. Then there will be a complex exponential that you can factor out part of to get a very simple result. Dirk
Reply by ●June 4, 20092009-06-04
Thanks Dirk, but can you elaborate abit on what I have to do to work out an 'infinite sum'. I've never come across the term before and haven't been able to gain any useful information by googling it. cheers, BriWel>On Jun 4, 2:21=A0pm, "briwel" <briwe...@hotmail.co.uk> wrote: >> Cheers Clay, >> >> I am currently revising for a DSP exam, so this isn't assessedhomework>> but more of a practice question so I can get the technique right. >> >> 1. So the impulse respone is 0.5*DELTA(n) + 0.5*DELA(n - 2) >> 2. I then need to take the FT of that, which is: >> >> INTEGRALOF((0.5*DELTA(n) + 0.5*DELA(n - 2))* e^(i*2*pi*f*n)) >> >> However, I'm not sure how to take the integral of a delta function,can>> anyone give me some advice? >> >> Thanks alot >> >> >> >> >On Jun 4, 9:13=3DA0am, "briwel" <briwe...@hotmail.co.uk> wrote: >> >> I have an FIR filter equation, which is >> >> y(n) =3D3D 0.5x(n) + 0.5x(n - 2). >> >> >> I have to draw the magnitude of the frequency response of thisfilter?>> >> Does anyone know how to do this? >> >> >> thanks in advance for any help >> >> >1st find the impulse response of your filter (trivial in this case) >> >2nd find the fourier transform of the impulse response. (quite simple >> >in this case) >> >3rd find the magnitude of the fourier transform found =A0in step 2. >> >> >We don't mind giving hints on homework problems but please identify >> >that you are doing a homework problem. >> >> >Clay- Hide quoted text - >> >> - Show quoted text - > > >Do an infinite sum, it only has 2 non-zero terms. Then there will be >a complex exponential that you can factor out part of to get a very >simple result. > >Dirk >
Reply by ●June 4, 20092009-06-04
Thanks Dirk, but can you elaborate abit on what I have to do to work out an 'infinite sum'. I've never come across the term before and haven't been able to gain any useful information by googling it. cheers, BriWel>On Jun 4, 2:21=A0pm, "briwel" <briwe...@hotmail.co.uk> wrote: >> Cheers Clay, >> >> I am currently revising for a DSP exam, so this isn't assessedhomework>> but more of a practice question so I can get the technique right. >> >> 1. So the impulse respone is 0.5*DELTA(n) + 0.5*DELA(n - 2) >> 2. I then need to take the FT of that, which is: >> >> INTEGRALOF((0.5*DELTA(n) + 0.5*DELA(n - 2))* e^(i*2*pi*f*n)) >> >> However, I'm not sure how to take the integral of a delta function,can>> anyone give me some advice? >> >> Thanks alot >> >> >> >> >On Jun 4, 9:13=3DA0am, "briwel" <briwe...@hotmail.co.uk> wrote: >> >> I have an FIR filter equation, which is >> >> y(n) =3D3D 0.5x(n) + 0.5x(n - 2). >> >> >> I have to draw the magnitude of the frequency response of thisfilter?>> >> Does anyone know how to do this? >> >> >> thanks in advance for any help >> >> >1st find the impulse response of your filter (trivial in this case) >> >2nd find the fourier transform of the impulse response. (quite simple >> >in this case) >> >3rd find the magnitude of the fourier transform found =A0in step 2. >> >> >We don't mind giving hints on homework problems but please identify >> >that you are doing a homework problem. >> >> >Clay- Hide quoted text - >> >> - Show quoted text - > > >Do an infinite sum, it only has 2 non-zero terms. Then there will be >a complex exponential that you can factor out part of to get a very >simple result. > >Dirk >
Reply by ●June 4, 20092009-06-04
On Jun 4, 3:27�pm, "briwel" <briwe...@hotmail.co.uk> wrote:> Thanks Dirk, but can you elaborate abit on what I have to do to work out an > 'infinite sum'. I've never come across the term before and haven't been > able to gain any useful information by googling it. > > cheers, > BriWel > > > > > > >On Jun 4, 2:21=A0pm, "briwel" <briwe...@hotmail.co.uk> wrote: > >> Cheers Clay, > > >> I am currently revising for a DSP exam, so this isn't assessed > homework > >> but more of a practice question so I can get the technique right. > > >> 1. So the impulse respone is 0.5*DELTA(n) + 0.5*DELA(n - 2) > >> 2. I then need to take the FT of that, which is: > > >> INTEGRALOF((0.5*DELTA(n) + 0.5*DELA(n - 2))* e^(i*2*pi*f*n)) > > >> However, I'm not sure how to take the integral of a delta function, > can > >> anyone give me some advice? > > >> Thanks alot > > >> >On Jun 4, 9:13=3DA0am, "briwel" <briwe...@hotmail.co.uk> wrote: > >> >> I have an FIR filter equation, which is > >> >> y(n) =3D3D 0.5x(n) + 0.5x(n - 2). > > >> >> I have to draw the magnitude of the frequency response of this > filter? > >> >> Does anyone know how to do this? > > >> >> thanks in advance for any help > > >> >1st find the impulse response of your filter (trivial in this case) > >> >2nd find the fourier transform of the impulse response. (quite simple > >> >in this case) > >> >3rd find the magnitude of the fourier transform found =A0in step 2. > > >> >We don't mind giving hints on homework problems but please identify > >> >that you are doing a homework problem. > > >> >Clay- Hide quoted text - > > >> - Show quoted text - > > >Do an infinite sum, it only has 2 non-zero terms. �Then there will be > >a complex exponential that you can factor out part of to get a very > >simple result. > > >Dirk- Hide quoted text - > > - Show quoted text -What course is this for?
Reply by ●June 4, 20092009-06-04
Its for Digital Communication and Signal Processing, a second year undergraduate computer science module. But its the first time in a few years I've had to do complex maths and the lecture notes are awful at best!
Reply by ●June 4, 20092009-06-04
briwel wrote:> Thanks Dirk, but can you elaborate abit on what I have to do to work out an > 'infinite sum'. I've never come across the term before and haven't been > able to gain any useful information by googling it.inf'ty Summation(x[n]) n = 0 -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
