Solving DSP problem
in [DSP]
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From: Richello on 18 Jan 2010 10:25 Dear Sir, Could you please help me to solve this or give me hints to do so? An analogue signal x(t)=10cos(500πt) is sampled at 0, T,2T, .... with T=1ms. I want to find a cosine y(t), whose frequency is as close as possible to that of x(t), which when sampled with T=1ms yields the same sample values as x(t). how can I get the equation of y(t)? .. then if x(nT) were the input to a D/A converter, followed by a low-pass smoothing filter, why would the output be x(t) and not y(t) ?
From: Tim Wescott on 18 Jan 2010 10:32 On Mon, 18 Jan 2010 09:25:50 -0600, Richello wrote: > Dear Sir, > > Could you please help me to solve this or give me hints to do so? > > An analogue signal x(t)=10cos(500πt) is sampled at 0, T,2T, .... with > T=1ms. > > I want to find a cosine y(t), whose frequency is as close as possible to > that of x(t), which when sampled with T=1ms yields the same sample > values as x(t). how can I get the equation of y(t)? .. then if x(nT) > were the input to a D/A converter, followed by a low-pass smoothing > filter, why would the output be x(t) and not y(t) ? 1: The solution as you state the problem is trivial: y(t) = x(t). I assume you mean the frequency should be close to but different. 2: Have you asked your prof? 3: Read this: http://www.wescottdesign.com/articles/Sampling/ sampling.html. Skip down to the part about aliasing. -- www.wescottdesign.com
From: invalid on 18 Jan 2010 11:00 "Tim Wescott" <tim(a)seemywebsite.com> wrote in message news:JfmdnWt5A4KS4snWnZ2dnUVZ_uBi4p2d(a)web-ster.com... > 3: Read this: http://www.wescottdesign.com/articles/Sampling/ > sampling.html. Skip down to the part about aliasing. Rejects attempts to read with error 403
From: Tim Wescott on 18 Jan 2010 11:48 On Mon, 18 Jan 2010 16:00:18 +0000, invalid wrote: > "Tim Wescott" <tim(a)seemywebsite.com> wrote in message > news:JfmdnWt5A4KS4snWnZ2dnUVZ_uBi4p2d(a)web-ster.com... >> 3: Read this: http://www.wescottdesign.com/articles/Sampling/ >> sampling.html. Skip down to the part about aliasing. > > Rejects attempts to read with error 403 Your newsreader (or mine) put the last bit on the following line. Try this one, all one line from the 'http' to the following 'html': http://www.wescottdesign.com/articles/Sampling/sampling.html. -- www.wescottdesign.com
From: Richard Dobson on 18 Jan 2010 11:52
On 18/01/2010 16:00, invalid wrote: > "Tim Wescott"<tim(a)seemywebsite.com> wrote in message > news:JfmdnWt5A4KS4snWnZ2dnUVZ_uBi4p2d(a)web-ster.com... >> 3: Read this: http://www.wescottdesign.com/articles/Sampling/ >> sampling.html. Skip down to the part about aliasing. > > Rejects attempts to read with error 403 > > Watch for line-wrap. The URL ends with "/sampling.html". Very common problem! Richard Dobson |