Forums

MUSIC in time domain

Started by gauthief March 6, 2007
hi evry body

i have seen a lot of mail about MUSIC to determine AOA but I would
like to separate signals at one frequency separated by a pase shift
due to propagation. does any body have a soft to do that?

thank you

Frederic

Frederic wrote:
> ... I would > like to separate signals at one frequency separated by a pase shift > due to propagation. does any body have a soft to do that?
So you have a signal at one frequency, say w0. The signal is sent into a channel with transfer function 1 + A z^-T, where A is the weighting and T is the delay of the echo. Using an input/output sinusoid pair at w0, you want to determine A and T. Is that correct? Regards, Andor
On 6 mar, 15:18, "Andor" <andor.bari...@gmail.com> wrote:
> Frederic wrote: > > ... I would > > like to separate signals at one frequency separated by a pase shift > > due to propagation. does any body have a soft to do that? > > So you have a signal at one frequency, say w0. The signal is sent into > a channel with transfer function > > 1 + A z^-T, > > where A is the weighting and T is the delay of the echo. Using an > input/output sinusoid pair at w0, you want to determine A and T. Is > that correct? > > Regards, > Andor
yes thats correct, in fact I have the signal at different frequency values but i have use an algorithm (Generalise Pencil of Function) to obtaine the signal for each frequency. The basic signal is the transfert function of the electrical line in an house where there is a lot of reflection and i would like, if possible, to obtaine the informations for each path. thank you Regards Fr=E9d=E9ric
On 6 Mar, 16:03, "gauthief" <frederic.gauth...@orange-ftgroup.com>
wrote:
> On 6 mar, 15:18, "Andor" <andor.bari...@gmail.com> wrote: > > > > > > > Frederic wrote: > > > ... I would > > > like to separate signals at one frequency separated by a pase shift > > > due to propagation. does any body have a soft to do that? > > > So you have a signal at one frequency, say w0. The signal is sent into > > a channel with transfer function > > > 1 + A z^-T, > > > where A is the weighting and T is the delay of the echo. Using an > > input/output sinusoid pair at w0, you want to determine A and T. Is > > that correct? > > > Regards, > > Andor > > yes thats correct, in fact I have the signal at different frequency > values but i have use an algorithm (Generalise Pencil of Function) to > obtaine the signal for each frequency. The basic signal is the > transfert function of the electrical line in an house where there is a > lot of reflection and i would like, if possible, to obtaine the > informations for each path.
So you want to find the parameters of a model f(t) = A cos(wt) + B cos(wt+phi) Let's take a closer look: f(t) = A/2 (exp(jwt)+exp(-jwt)) + B/2 (exp(jwt+phi)+exp(-jwt-phi)) = (A+B)exp(phi)/2 (exp(jwt) + exp(-jwt)) = C/2(exp(jwt)+exp(-jwt)) = C cos(wt). So using a time domain measuremet, you can not separate the signal from the reflection. Rune
On 6 mar, 16:55, "Rune Allnor" <all...@tele.ntnu.no> wrote:
> On 6 Mar, 16:03, "gauthief" <frederic.gauth...@orange-ftgroup.com> > wrote: > > > > > > > On 6 mar, 15:18, "Andor" <andor.bari...@gmail.com> wrote: > > > > Frederic wrote: > > > > ... I would > > > > like to separate signals at one frequency separated by a pase shift > > > > due to propagation. does any body have a soft to do that? > > > > So you have a signal at one frequency, say w0. The signal is sent into > > > a channel with transfer function > > > > 1 + A z^-T, > > > > where A is the weighting and T is the delay of the echo. Using an > > > input/output sinusoid pair at w0, you want to determine A and T. Is > > > that correct? > > > > Regards, > > > Andor > > > yes thats correct, in fact I have the signal at different frequency > > values but i have use an algorithm (Generalise Pencil of Function) to > > obtaine the signal for each frequency. The basic signal is the > > transfert function of the electrical line in an house where there is a > > lot of reflection and i would like, if possible, to obtaine the > > informations for each path. > > So you want to find the parameters of a model > > f(t) =3D A cos(wt) + B cos(wt+phi) > > Let's take a closer look: > > f(t) =3D A/2 (exp(jwt)+exp(-jwt)) + B/2 (exp(jwt+phi)+exp(-jwt-phi)) > =3D (A+B)exp(phi)/2 (exp(jwt) + exp(-jwt)) > =3D C/2(exp(jwt)+exp(-jwt)) > =3D C cos(wt). > > So using a time domain measuremet, you can not separate > the signal from the reflection. > > Rune- Masquer le texte des messages pr=E9c=E9dents - > > - Afficher le texte des messages pr=E9c=E9dents -
ok, thank you y have tryed but with non succ=E8s the obtained result give the delay corresponding to the number of samples used to construct the autocorrelation function, so i thought that my programmation was wrong. Regards Fr=E9d=E9ric
On Mar 6, 1:21 am, "gauthief" <frederic.gauth...@orange-ftgroup.com>
wrote:
> hi evry body > > i have seen a lot of mail about MUSIC to determine AOA but I would > like to separate signals at one frequency separated by a pase shift > due to propagation. does any body have a soft to do that?
Is the source frequency a pure unmodulated sinusoid, or is it, or can it be, modulated in any way? Is the phase shifted portion of the signal combined purely linearly, or are the any non-linear effects between the signals? Even your AC line might be modulated, by, for instance, your neighbor's well pump relay kicking in, if you are on the same transformer. IMHO. YMMV. -- rhn A.T nicholson d.0.t C-o-M
hi,
   I believe..this can be done in ICA

http://www.cs.helsinki.fi/u/ahyvarin/whatisica.shtml

i remember..once..one of my colleague..was attempting using ICA..do
look at it once..

may be the seperation could be easy..but ..trying out different
methods..get a chance to know others..thats the good thing i guess

particlereddy








On Mar 6, 11:51 pm, "Ron N." <rhnlo...@yahoo.com> wrote:
> On Mar 6, 1:21 am, "gauthief" <frederic.gauth...@orange-ftgroup.com> > wrote: > > > hi evry body > > > i have seen a lot of mail about MUSIC to determine AOA but I would > > like to separate signals at one frequency separated by a pase shift
> > due to propagation. does any body have a soft to do that? > > Is the source frequency a pure unmodulated sinusoid, or is it, > or can it be, modulated in any way? Is the phase shifted portion > of the signal combined purely linearly, or are the any non-linear > effects between the signals? > > Even your AC line might be modulated, by, for instance, your > neighbor's well pump relay kicking in, if you are on the same > transformer. > > IMHO. YMMV. > -- > rhn A.T nicholson d.0.t C-o-M
On 6 Mrz., 16:03, "gauthief" <frederic.gauth...@orange-ftgroup.com>
wrote:
> On 6 mar, 15:18, "Andor" <andor.bari...@gmail.com> wrote: > > > > > > > Frederic wrote: > > > ... I would > > > like to separate signals at one frequency separated by a pase shift > > > due to propagation. does any body have a soft to do that? > > > So you have a signal at one frequency, say w0. The signal is sent into > > a channel with transfer function > > > 1 + A z^-T, > > > where A is the weighting and T is the delay of the echo. Using an > > input/output sinusoid pair at w0, you want to determine A and T. Is > > that correct? > > > Regards, > > Andor > > yes thats correct, in fact I have the signal at different frequency > values but i have use an algorithm (Generalise Pencil of Function) to > obtaine the signal for each frequency.
I wish I knew what the (Generalise Pencil of Function) algorithm is. Until then, you can procesd as follows: Input the signal x(t) = cos(w0 t) into the system. The output will be of the form y(t) = a cos(w0 t + phi). The frequency response is H(w) = 1 + A exp(- j w T). You can measure the two values a and phi and get two equations |H(w0)| = a, arg(H(w0)) = phi, from which you can determine A and T modulo w0/(2 pi). This means that if your delay is large, you need very low frequency measurement tone. Regards, Andor
On 6 Mrz., 16:55, "Rune Allnor" <all...@tele.ntnu.no> wrote:
> On 6 Mar, 16:03, "gauthief" <frederic.gauth...@orange-ftgroup.com> > wrote: > > > > > > > On 6 mar, 15:18, "Andor" <andor.bari...@gmail.com> wrote: > > > > Frederic wrote: > > > > ... I would > > > > like to separate signals at one frequency separated by a pase shift > > > > due to propagation. does any body have a soft to do that? > > > > So you have a signal at one frequency, say w0. The signal is sent into > > > a channel with transfer function > > > > 1 + A z^-T, > > > > where A is the weighting and T is the delay of the echo. Using an > > > input/output sinusoid pair at w0, you want to determine A and T. Is > > > that correct? > > > > Regards, > > > Andor > > > yes thats correct, in fact I have the signal at different frequency > > values but i have use an algorithm (Generalise Pencil of Function) to > > obtaine the signal for each frequency. The basic signal is the > > transfert function of the electrical line in an house where there is a > > lot of reflection and i would like, if possible, to obtaine the > > informations for each path. > > So you want to find the parameters of a model > > f(t) = A cos(wt) + B cos(wt+phi) > > Let's take a closer look: > > f(t) = A/2 (exp(jwt)+exp(-jwt)) + B/2 (exp(jwt+phi)+exp(-jwt-phi)) > = (A+B)exp(phi)/2 (exp(jwt) + exp(-jwt))
I would rethink the above two lines.
> = C/2(exp(jwt)+exp(-jwt)) > = C cos(wt).
You don't *really* believe that, do you :-).
> > So using a time domain measuremet, you can not separate > the signal from the reflection. > > Rune
Regards, Andor
On 6 mar, 19:51, "Ron N." <rhnlo...@yahoo.com> wrote:
> On Mar 6, 1:21 am, "gauthief" <frederic.gauth...@orange-ftgroup.com> > wrote: > > > hi evry body > > > i have seen a lot of mail about MUSIC to determine AOA but I would > > like to separate signals at one frequency separated by a pase shift > > due to propagation. does any body have a soft to do that? > > Is the source frequency a pure unmodulated sinusoid, or is it, > or can it be, modulated in any way? Is the phase shifted portion > of the signal combined purely linearly, or are the any non-linear > effects between the signals? > > Even your AC line might be modulated, by, for instance, your > neighbor's well pump relay kicking in, if you are on the same > transformer. > > IMHO. YMMV. > -- > rhn A.T nicholson d.0.t C-o-M
good morning the source is frequency is not modulated and it should be a lot work to perform a modulation. I am now try to synchronize the transmission and the reiciver using a radio link, so if I can keep in memorie the phase of the transmitted signal i can do a king of radar. I have to program to see the phase shift. what is the idea? thank you for your comments Fr=E9d=E9ric