Here, in this article we will discuss about Manchester Code Encoder and Decoder, its key parameters and application.
Description of Manchester Code Encoder and Decoder
This IC provides both encoding and decoding functions of the Manchester 2 Code used in military and industrial communications systems. It is divided into two sections, the encoder and the decoder, which operate independently of each other, except for the master reset. While specifically designed to meet the requirements of MIL-STD-1553, this IC also can be used for other time-division multiplexed serial data protocols.
As illustrated in the function block of Figure 1, this 24-pin IC can operate either on bipolar or unipolar data, allowing it to work with a variety of communications systems. The encoder requires two clock signals – the “send” clock, which is twice the desired data rate, and the “encoder” clock, which is six times the data rate. Both encoder and decoder functions contain counters and a variety of other digital elements, but their operation is too complex for detailed description in this article. The reader is referred to manufacturer’s data.
Key Parameters
This IC is currently only available as a CMOS device and its electrical characteristics are essentially those of the CMOS digital IC family.
- Maximum clock frequency: The maximum clock frequency for either encoder or decoder is 15 MHz.
- Maximum data rate:25 megabaud. To assure stability over the entire temperature range, the manufacturer recommended a maximum range of 1 megabaud.
- Typical operating power: 50 mW is specified of 5V power supply over the standard temperature range.
Applications
This IC is specifically designed to provide the encoding and decoding function for a time-division multiplexed data bus using the Manchester 2 code. Aircraft interior communications, both military and commercial, are a typical use for this kind of system.
Representative Part Number: Harris HD6409.
Comments:
Because of the unique and complex nature of this IC, the reader is urged to obtain manufacturers’ application data before using this IC for new design.