What is the concept Auto Scan Frequency in Mobile?

auto scan frequency

How does a Auto Scan Frequency in Mobile FM's Work?
I mean how does the auto scaning fequency in mobile stops to scan when it catches the freq. signal which is strong enough. what is the concept behind it...?

Can similar concept could be used to detect a tone (test tone or any normal speech tone) by manually changing the freq(thru variable pot or so) in my detector circuit. If no is there any alternative to LMC 567.

autoscan circuit

You have asked this before. Why don't you continue your previous thread instead of scheduling the question a new?

I see only a loose relation between both problems, thus I'll refer to your main question.

To start with 567, it's a tone decoder with a rather small bandwidth of 14%, so it's not suited for observing a larger frequency band. It's also not designed to provide amplitude information.

A tunable filter, as suggested by the scanner example, can basically work, but it's possibly unsuitable for a varying signal. My basic problem is, that you didn't exactly tell what you want to achieve. Analysis of acoustic signals can be rather simple or very complex, depending on the signal type and the parameters you want to extract.

To mention two existing solutions with different sound analysis properties:
- A guitar tuner. It performs an exact frequency measurement of a single, pure tone. The tone must have a minimum duration and shouldn't be affected by a high noise level.
- A real-time audio spectrum analyzer. It displays the varying amplitude for a limited number of bands, e.g. 10 or 30, that are equally distributed over the audio frequency range. Respectively, the frequency resolution is rather limited.

lmc567 alternatives

first and foremost, I am Sorry for making multiple threads.

My basic idea originated when i saw a Test tone generator.
And i thought of making a tone decoder. What clicked me at that time is the idea of resonance (here i still am talkin of a single freq signal).
I came to know of a IC 567 here.
My idea flourished to make a decoder for complex signals too.

Sooner i thought or extracting other parameters (amp., Wave type, both if possible)

so my problem is to make my tone detector work without 567 for singe freq signals ( which is prety easy) but also for complex signals like an audio tape or a speech signal. I'm seeking help regarding this. thanks FvM...!!