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filter out noise of EMIC — Parallax Forums

filter out noise of EMIC

shmowshmow Posts: 109
edited 2009-09-28 00:18 in General Discussion
Hello All,
I have an EMIC that I've been tinkering with, and no matter how much altering from the programming side, I can't eliminate the noise in the background - when she "speaks". Is there an RC circuit I can apply (I'm a novice, so that's what I'm thinking) to filter out the noise?
Any advice would be very helpful.
Regards,
Shmow

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-09-23 16:57
    How are you providing power to the EMIC? What sort of noise is it? Is it a hum? Is it high frequency noise? Is it a hissing noise? Is it just distortion of the output voice? Have you hooked up the EMIC properly? All these questions are important to figure out what you need.
  • shmowshmow Posts: 109
    edited 2009-09-24 14:50
    Hello Mike,
    The EMIC is powered from the 5VDC terminal on the prop demo board.
    I have a 1k ohm resistor in series between the "SOUT" pin on my prop and the SIN pin on the EMIC.
    The two EMIC GND pins are connected to the demo board's VSS terminal.
    The noise has a hissing quality to it, but I believe it could be just the distortion of the voice.
    Regards,
    Shmow
  • dev/nulldev/null Posts: 381
    edited 2009-09-24 23:28
    I have the same problem. I have 5V coming from a 7805 (there is absolutely no noise on the SIn pin or the power lines, I checked with a oscilloscope).
    The sound is like the hissing sound you hear from walkie-talkies.

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  • Mike2545Mike2545 Posts: 433
    edited 2009-09-27 23:13
    I also have this hissing noise from mine. Like bad taped audio. A little disappointing for what was charged for the unit.

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    Mike2545

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  • Tracy AllenTracy Allen Posts: 6,666
    edited 2009-09-28 00:18
    I know what you mean. You can hear that hiss in my automated windtalker weather station on Mt. Tamalpais (1-415-381-9463). The EMIC there is feeding the voice port on a modem, controlled by a BASIC Stamp. If you hold the telephone receiver a little farther away from your ear, the hiss seems less apparent, so maybe the secret is to add ambient noise! Another thing, the Emic swallows final consanants, like the "n" that distinguishes "thirteen" from "thirty".

    The first stage of speech synthesis is a hiss or noise generator that is subsequently modulated in the vocal tract, and I suspect that what we hear is the residue of that. You can learn a lot about speech by looking at Chip's development of the speech synth object for the Propeller.

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    Tracy Allen
    www.emesystems.com
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