How to determine the frequency of the signal in chips?

[watertreader]

Calculating Frequency

Hi,

Just wonder is there any method/chip to determine the frequency of the signal in chips or ciruit level (beside using oscillscope and match filter) ?

Thanks

 

[Euler's Identity]

Re: Calculating Frequency

I'm not sure I'm understanding what exactly you want, but you could also use a spectrum analyzer and determne the frequency of the fundamental spur.

Or is it that you're wanting a chip or a circuit that determines the frequency?

I know there's a gizmo (which I've never used nor know anything about) called the FFT (Fast Fourier Transform) where, given an input signal, the output is the FFT, the frequency content of the signal. Moreover, I'd recommend looking into finding FFT IC's, as I know they exist, perhaps only as processors.

(Granted, I know about the Fourier Transform, which may be the same as finding a Fourier Series, but I know nothing about the FFT beyond what I've said.)

P.S. To anyone reading, if you know more about the FFT, please speak up, as I'd like to know more about it. For example, is it an abridged Fourier Series of a signal/waveform?

 

[watertreader]

Re: Calculating Frequency

Thanks for the reply!

I would need a chip to measure the frequency of the input signal. The output would be needed to adjust for some settings for the filter at the latter stage. Hence some voltage signal level might be required

Thanks once again

 

[leoren_tm]

Re: Calculating Frequency

i think there is no chip for that!!!!

 

[manojshukla]

Re: Calculating Frequency

one method may be to measure the frequeny of redaition emiiting from it. The same will be the resultsnt frequency.

 

[pnnavigator0915]

Re: Calculating Frequency

I'm not sure I'm understanding what exactly you want, but you could also use a spectrum analyzer and determne the frequency of the fundamental spur.

Or is it that you're wanting a chip or a circuit that determines the frequency?

I know there's a gizmo (which I've never used nor know anything about) called the FFT (Fast Fourier Transform) where, given an input signal, the output is the FFT, the frequency content of the signal. Moreover, I'd recommend looking into finding FFT IC's, as I know they exist, perhaps only as processors.

(Granted, I know about the Fourier Transform, which may be the same as finding a Fourier Series, but I know nothing about the FFT beyond what I've said.)

P.S. To anyone reading, if you know more about the FFT, please speak up, as I'd like to know more about it. For example, is it an abridged Fourier Series of a signal/waveform?

Well FFT ICs are quite a good suggestion for frequency measurement. But now a days we are equipped with lots of new things like DSPs, ASICs etc.. We can program the DSPs especially meant for frequency to voltage converstion and direct digital compatible output for LED/LCDs.

About FFT, it's a fourier transform that means it shows the spread of a signal over the frequency axis. Or may be i can say that, you use fourier series when you need to analyse a Periodic Behavior specifically, coz it wont give more diracs on graph and FFT is a better way to measure non periodic functions and signal analysis of such data signals which are not having a predefined period.

Infact you can say FFT when divided into two we get Fourier series!!