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Frequency detection

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As a part of a project i need some sort of frequency detection.

Input will be with a microphone, and output would be a digital signal based on the input frequency. For example, if input is 440Hz, a series of ICs would output the binary value 0001.

How would one accomplish this? Is there a some sort IC that outputs the frequency in binary availible.

If it is relevant, i am building a digital circuit that is supposed to react differently on different sine-wave sounds in the area of aprox 300 - 10000Hz.
It does not have to be too acurate, as long as it makes the circuit react differently on atleast 10 different notes.

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Dear jarmund

the sound of a human (your circuit input) consists of too many harmonics and difeerent frequencies. Usaully, the input of frequency meters are PURE sin or Square Waves.
U can take a look at your graphic equalizer to understand what I mean!!!
If you want a circuit to determine the frequency of a pure wave, then it is just a simple frequency meter. Too many of them on the web.

HTH - Shahriar

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Actually, the input is not a human voice, it will be from a signal generator to make sure the frequency is exactly the ones desired.

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Hi Jarmund

personally I'd use a PIC processor, first use an op-amp with plenty of gain to amplify the sine wave so that it clips at the supply voltage - you now have a square wave at the input frequency.  Feed this square wave into a PIC, ensuring that the input square wave is within the correct voltage range and write some software to measure the time between each transition of the input signal.

You are then free to use the PIC output ports to give the digital representation in any form you require, you could have a software routine which will set the 4 bits based on a linear or other division of the input frequency range

Ed

Tricky!!!  ;)

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• 1 month later...

hi LOOK  IC LM567

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