Re: maximum confirmed software transmit carrier?

[Stephen D. <st...@da...>]

On Sat, 1 Jun 2002, Scott Baily wrote:

> Seeing these results, I modified the transmitter to use the TX pin rather
> than DTR.  This way I can use the UART to generate the carrier frequency.
> 38400 Hz with a duty cycle of 1/3 or 2/3 would control my JVC and yamaha
> devices, but not my proscan device. 57600 (50 percent duty cycle) would
> control all three devices. So I don't think that the 38 kHz receivers have
> very narrow bandpass filters.

The IRDEO uses this technique to make the carrier.  Its clever and very
easy on the CPU.

Most receivers aren't very touchy - but some are.  My NTL and Sky Digital
receivers didn't want to know the IR signals from the IRDEO or from the
LIRC lirc_serial originally.  That's what prompted my changes to
lirc_serial last year.

Steve