>>Hi,
>>
>>I have a sinusodal signals with fixed frequencies(multi-tone).
>>But the signal is randomly on and off.
>>What I did is that once the signal is off, I discarded the portion and,
>>then, when the signal is on, I attached the signal afterward.
>>So, now, the signal becomes phase discontinued, same frequency,though.
>>
>>My frequency tracking algorithm works with the original sinusoidal
>>signals(without off). Not it cannot track the phase-discontinued signal
>>properly.
>>Is there any way to track the frequency of the signal?
>>
>>Thank you in advance.
>>timothy
>>
>
>Hi,
>
>How do you track the frequencies?
>If you use a fft-based method (looking for peaks),
>I think it might be better if you leave the "off-parts"
>in. The multiplies with zeros for the "off-parts"
>will introduce spurious peaks, but you could
>use an algorithm which "puts a question-mark" to all new
>peak in a new STFT frame and just considers to track them
>if they appear in more than one succesive STFT frame.
>
>It really depends on:
>
>1. What method are you using to track the frequencies of
> the sinusoids?

I use DFT filters to track frequency. FFT doesn't work in my case becaus
I need precise frequency tracking.

Furthermore, the off signal may have different frquency, i.e on freq i
15.65 Mhz and off freq is 16.59 Mhz. In this case, I have to track 15.6
Mhz freq. of course it has on/off switches.

>
>2. What is the ratio between "on" and "off" parts?
> How much of the signal is dropped?

It is RANDOM for now.


>
>Splicing the signals together doesn't seem to make too much
>sense. But maybe I'm wrong...
>
>gr.
>Bjoern
>
>