Hello, I want to generate cosine signal from the sine signal avaiable. What all different techniques by which i can do it???? Hilbert transform????how to do this using hilbert transform. Any reference or suggestion will be great.... This sin and cos is for Iq demodulation I will be first testing it on matlab and then on DSP waiting for reply with regards praveen

# cosine generation from sine signal in DSP

Started by ●July 28, 2003

Reply by ●July 28, 20032003-07-28

On 28 Jul 2003, praveen wrote:> Hello, > I want to generate cosine signal from the sine signal avaiable. > What all different techniques by which i can do it???? > Hilbert transform????how to do this using hilbert transform. > Any reference or suggestion will be great.... > This sin and cos is for Iq demodulation > I will be first testing it on matlab and then on DSP > waiting for reply > with regards > praveen >just delay it by -pi/2. -- The most rigorous proofs will be shown by vigorous handwaving. http://www.mit.edu/~kusuma opinion of author is not necessarily of the institute

Reply by ●July 28, 20032003-07-28

praveenkumar1979@rediffmail.com (praveen) wrote in message news:<ff8a3afb.0307280251.3d106579@posting.google.com>...> Hello, > I want to generate cosine signal from the sine signal avaiable. > What all different techniques by which i can do it???? > Hilbert transform????how to do this using hilbert transform. > Any reference or suggestion will be great.... > This sin and cos is for Iq demodulation > I will be first testing it on matlab and then on DSP > waiting for reply > with regards > praveenWhy not to use a quadrature oscillator for generating both the sine and cosine signals simultaneously? Another idea, which actually doesn't make much sense to me, though, is to delay the sine signal by pi/4... JaaC

Reply by ●July 28, 20032003-07-28

praveenkumar1979@rediffmail.com (praveen) wrote in message news:<ff8a3afb.0307280251.3d106579@posting.google.com>...> Hello, > I want to generate cosine signal from the sine signal avaiable. > What all different techniques by which i can do it???? > Hilbert transform????how to do this using hilbert transform. > Any reference or suggestion will be great.... > This sin and cos is for Iq demodulation > I will be first testing it on matlab and then on DSP > waiting for reply > with regards > praveenSince you want to try this on a DSP/Matlab, and if you can generate a sine signal of the desired frequency then you can also surely generate a cosine signal also (w/o hilbert transformer). The exact implementation would depend on the way you are generating a sine signal. Hilbret transformer (PI/2 delay filter) can be implemented as a fir filter. A related application note is "Implementation of an FSK Modem Using the TMS320C17", Application Report: SPRA080, Texas Instruments, 1997 - You can find this on <http://www.ti.com> Hope this helps. Sachin

Reply by ●July 28, 20032003-07-28

On Mon, 28 Jul 2003 08:16:12 -0400, Julius Kusuma <kusuma@mit.edu> wrote:> >On 28 Jul 2003, praveen wrote: > >> Hello, >> I want to generate cosine signal from the sine signal avaiable. >> What all different techniques by which i can do it???? >> Hilbert transform????how to do this using hilbert transform. >> Any reference or suggestion will be great.... >> This sin and cos is for Iq demodulation >> I will be first testing it on matlab and then on DSP >> waiting for reply >> with regards >> praveen >> > >just delay it by -pi/2.Or take the derivative... Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org

Reply by ●July 28, 20032003-07-28

praveenkumar1979@rediffmail.com (praveen) wrote in message news:<ff8a3afb.0307280251.3d106579@posting.google.com>...> Hello, > I want to generate cosine signal from the sine signal avaiable. > What all different techniques by which i can do it???? > Hilbert transform????how to do this using hilbert transform. > Any reference or suggestion will be great.... > This sin and cos is for Iq demodulation > I will be first testing it on matlab and then on DSP > waiting for reply > with regards > praveenHow is the cosine signal generated/stored? What frequency resolution is required? What kind of signals (general type) are you planning to I/Q demod (AM, FM, SSB, ISB, ...)? Dirk Dirk A. Bell DSP Consultant

Reply by ●July 28, 20032003-07-28

"Julius Kusuma" <kusuma@mit.edu> wrote in message news:Pine.GSO.4.33L.0307280815410.13823-100000@magic-pi-ball.mit.edu...> > On 28 Jul 2003, praveen wrote: > > > Hello, > > I want to generate cosine signal from the sine signal avaiable. > > What all different techniques by which i can do it???? > > Hilbert transform????how to do this using hilbert transform. > > Any reference or suggestion will be great.... > > This sin and cos is for Iq demodulation > > I will be first testing it on matlab and then on DSP > > waiting for reply > > with regards > > praveen > > > > just delay it by -pi/2. >Praveen, You say "generate" but not in what context. First, assuming that it is a constant sinusoid then: If it's a software functional generator then as Julius suggests: cos(x)=sin(x+pi/2) If it's a table lookup: cos(n)=sin(n+k) where k is a number of samples equivalent to pi/2 If it's an input then delay by 3*pi/2 = -pi/2 If it's not a constant sinusoid, then you may indeed want to use a Hilbert transformer / filter to get wider band results. Fred

Reply by ●July 28, 20032003-07-28

I had to do this recently and, for my application, using the common identity cos = sqrt(1-sin^2) worked for me. It wasn't a signal generator, I just needed a single value and in only 2 quadrants, so this technique might not be appropriate for you. "praveen" <praveenkumar1979@rediffmail.com> wrote in message news:ff8a3afb.0307280251.3d106579@posting.google.com...

Reply by ●July 28, 20032003-07-28

Eric Jacobsen wrote:> > On Mon, 28 Jul 2003 08:16:12 -0400, Julius Kusuma <kusuma@mit.edu> > wrote: > > > > >On 28 Jul 2003, praveen wrote: > > > >> Hello, > >> I want to generate cosine signal from the sine signal avaiable. > >> What all different techniques by which i can do it???? > >> Hilbert transform????how to do this using hilbert transform. > >> Any reference or suggestion will be great.... > >> This sin and cos is for Iq demodulation > >> I will be first testing it on matlab and then on DSP > >> waiting for reply > >> with regards > >> praveen > >> > > > >just delay it by -pi/2. > > Or take the derivative...Too noisy. Integrate and invert. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������

Reply by ●July 29, 20032003-07-29