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Corrective Duty-Cycle Decoder for Infrared Manchester Data Transmission Disclosure Number: IPCOM000061614D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09

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Zalph, W Munoz-Bustamante, C Campbell, T [+details]


This article describes a waveform duty cycle reconstruction circuit arrangement for infrared (IR) data transmission utilizing the Manchester data encoding method. However, it is not limited to use with Manchester but can be used with other encoding schemes. Manchester encoding can be used for IR data transmission. Manchester has a 50%/50% duty cycle with one transition in the middle of each bit cell. A positive transition denotes a logical 0, a negative transition denotes a logical 1. IR data transmission through the air with a 50%/50% duty-cycle will not be received in all places with a 50%/50% duty cycle. Duty-cycle degradation is caused by ever-decreasing signal-to-noise (S/N) ratios of the transmitted signal as a function of transmitter-to-receiver distance.