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The datasheet says the maximum detection bandwidth is 10% of center frequency. If your center frequency is 1.2kHz (geometric mean of 500 and 3000), then the maximum bandwidth you can get will be 120Hz. It won't work.
Why do you think you need a filter before your detection circuitry?
What do you mean cover?
Does it matter if it amplifies other frequencies as well?
What's wrong with a simple op-amp?
Hi Freddy.
What is your end application for such frequency detection? If you're after a sharp cut-off frequency for your detector, it could be tough. An extreme solution would be to use the 567 with an analogue switch or digital pot to sweep the center frequency across 500 to 3000Hz, and a latch on the output to detect any output pulses. But its response would be slow.
There may be other solutions using a 555 timer as a sort of pseudo missing pulse detector. But as I said it really depends on what you are using this for.
Blueteeth
are you reffering to the lm567, ive been told its obselete now.
Detecting tones in such a wide range will be VERY prone to falsing on noise and will trigger on any voice traffic.is it possible to get a single LM567 chip to detect tones between 500hz and 3000hz?
Detecting tones in such a wide range will be VERY prone to falsing on noise and will trigger on any voice traffic.
If you still want to do this you could cascade multipole filters, one 500Hz highpass and one 3Khz lowpass, followed by a simple diode detector.
Now if you are just trying to detect two tones, 500Hz and 3Khz, then a reliable detector can be made with just two LM567s and some simple logic.
hi freddy,
Would detecting any frequency between 500Hz and 3Khz be acceptable.?
In other words if a frequency was detected between these limits a 'detect flag/bit' or 'alarm' was given
OR
do you need to know the frequency being detected.?
Here is a link to some software for designing the filters:sounds ideal, just what i need, but where do i start, can anyone help with circuit diagrams and values of components, its been a while since ive done anything like this and i dont really know what to do next
thanks for the reply, don't need to know the freqency...
what ideas have you got?
thanks
fred
hi freddy,
Its possible to use monostables and gates to give out a 'logic signal' when a frequency is within set limits.