Manchester is NRZ data X OR with data clock. If data is low or high you see the clock frequency the clock shifts half a cycle on each transistion. This was devloped for the IBM Data tape transports in the 60 of the last century. Its main advantage is the base line remains adverage of half the P-P of the data. The disadvantage is your baud rate and the modulation frequency are now the same rate.

Art, KC6UQH ----- Original Message ----- From: "RFI-EMI-GUY" Rhyolite@nettally.com To: "Jim Sanford" wb4gcs@amsat.org; amsat-bb@amsat.org Sent: Thursday, March 27, 2008 8:49 PM Subject: [amsat-bb] Re: MANCHESTER encosing schemes

Thanks Jim!

Jim Sanford wrote:

See Embedded Systems Design for Feb 2008. www.embedded.com 73 and good luck! Jim wb4gcs@amsat.org

RFI-EMI-GUY wrote:

...

Can anyone point me to some simple schemes for Manchester encoding and decoding. The application would be for high speed data over a low cost ISM link (manufacturer advises against long strings of data in 111 or 000's)