Re: CM11A hangup: Any better products?

[Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx>]

Hello Dave,

> None of the X-10 modules used in North America use crystals or resonators -
> all are LC tuned. This is true both for the 120kHz PLC modules as well as
> for their 310MHz and 418MHz wireless devices.

Well, that's not quite so IIRC. As George said the transmit can be
generated by the micro controller in a transmitter. All you need to do
is generate pulses of 8.3usec repetition rate and turn them on and off
as per the code you want to send. That is very easy to do with a uC and
I believe that's how the RR501 works. This pulse rate is controlled by
the crystal or resonator that operates the master clock of the uC. This
is going to be very accurate.

True, the signal then has to pass the LC circuit. It is, in RF terms,
usually a "class C" one-transistor stage where the base is driven hard
by a uC pin. The signal will be reduced in amplitude if the LC is out of
tune. So it can make sense to also peak this LC circuit to get the most
onto the line but it won't change the frequency.

> The 1132 circuitry designed by SmartHome is not at all similar to the PLC
> design used by X-10. I gave a link to a schematic for an X-10 made lamp
> module.

But a lamp module is only a receiver.

Regards, Joerg

http://www.analogconsultants.com