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Sine to Square - more info — Parallax Forums

Sine to Square - more info

ArchiverArchiver Posts: 46,084
edited 2003-07-23 00:02 in General Discussion
I forgot to say that the signal I need to convert comes from a variable
reluctance pickup and hence can range form mV to tens of volts.
Is that going to make a big difference to what I am trying to do?

Original Message
From: "Tim Stockman" <tim.stockman@s...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 22, 2003 10:29 PM
Subject: [noparse][[/noparse]basicstamps] Sine to Square


> Whats the easiest waht to convert a low frequency sine (10-100hz) to a
square wave? Opamps or a comparator?
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Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-07-23 00:02
    >I forgot to say that the signal I need to convert comes from a variable
    >reluctance pickup and hence can range form mV to tens of volts.
    >Is that going to make a big difference to what I am trying to do?
    >
    >
    Original Message
    >From: "Tim Stockman" <tim.stockman@s...>
    >To: <basicstamps@yahoogroups.com>
    >Sent: Tuesday, July 22, 2003 10:29 PM
    >Subject: [noparse][[/noparse]basicstamps] Sine to Square
    >
    >
    >> Whats the easiest waht to convert a low frequency sine (10-100hz) to a
    >square wave? Opamps or a comparator?
    > >

    One chip that is meant specifically for use with reluctance pickups
    is the old LM2917. It is a tachometer IC that can output a voltage
    proportional to input frequency. But if you leave off the
    "integration" capacitor, it will output a series of pulses at a rate
    of twice the sine wave input frequency. Those are pulses that can be
    counted by the BASIC Stamp. It is not a symmetrical square wave, if
    that is indeed what you need. The hysteresis is about 5 millivolts
    at the input, I think.

    -- Tracy
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