PIC 18Fxx2 PWM output

Hi everybody, what quality of sound i will have for speech on 10 bits PWM, '.wav' 22 kHz,16 bit? Please any estimation, especially negative.

Thanks in advance.

Reply to
Vic
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bit?

Well, it's sort-of, not-so umm, a bit better than, arr kind-a, you see... What do you expect to hear? The resolution determines noise and distortion, while the sample frequency limits the maximum speech frequency. Take a sample, recode it on your PC and estimate the quality yourself.

HTH, Michael

Reply to
Michael Hofmann

Hi Michael,

Clear sound are wanted. All examples i saw PWM wasn't used as codec. It needn't to invent square wheel if somebody did with bad result. On PC for sound are worked any program, hardly the samples transform directly. Of course i must be more industrious & to study theme, but it need the large time.

I can't understand, is this some laughter on me?

Best regards Victor

Reply to
Vic

You will find it's a lot easier to filter the PWM carrier frequency if you use say 8 bits @ 80kHz (which should be possisble given the specs you stated). The speech will seem clearer even though the resolution is only 8 bits.

I'd definitely recommend a low cost speech codec if you need decent quality.

One more thing - take care when you update the PWM values - some PWMs are double buffered and some are not. If not, you will see PWM glitches when the software updates the PWM value. Buffered PWMs reload the new value at a known counter value, usually 0.

-Andrew

Whytech MSP430 / PIC / AVR tools, SMD prototyping adaptors Imagecraft MSP430 C compilers

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kHz,16 bit?

Reply to
Whytech

Hi Andrew, i don't understand something, want to direct apply but haven't mail.

What mean 'filter' here?

I use now TLW codec but haven't clear voice. Therefore in desperate seek most cheap decision.

Are timer(counter) rigid connect with PWM & are rejected new values early?

Best regards Victor

Reply to
Vic

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