Differentiate and Dump Receiver Circuitry
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
This article describes a circuit arrangement with an active/passive filtering approach for infrared (IR) communication which increases the data rate of the IR media without sacrificing signal amplitude, while reducing the noise of 70 Khz fluorescent bulbs. The worst noise in the IR media is produced by high frequency fluorescent bulbs. They produce 70 Khz IR noise which is effectively filtered out by several stages of high-pass filtering, as illustrated in Fig. 1. It has been shown that compressed pulse position modulation (CPPM) is the most efficient encoding method for IR transmission. The best solution to date is the CPPM encoding scheme together with the filtering shown in Fig. 1. In CPPM, one pulse encodes 4 bits by detecting the arrival of a pulse in one of 16 possible time slots.