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Transmitting Data in a Serial Code

Transmitting Data in a Serial Code

NRZ Code. Synchronous Mode. NRZ (non return zero). A simple code for the transmission by two-wire line. The code consist of Start-bit , 6...8 Informative bits, Stop-bit. To transfer a Sync pulse used a pair of wires.

Fig. 1. Time Diagram of NRZ Code.

Transfer speeds can reach 64 Kbit/sek.

1 bit/sek = 1 Bd.

NRZ Code. Asynchronous Mode. Data in the NRZ code can be transferred without Sync pulses. Such Mode is asynchronous. Приём данных в этом случае синхронизируется в приёмнике, а частота синхронизации не должна различаться от частоты передачи передатчика более ± 5%, ибо при 8 битах данных, 1 старт бита и 1 стоп бита ±5% ·10 = ± 50%, а это - половина ширины периода одного бита данных. Admission data are synchronized in the receiver.

Manchester – II Code. The Data and Sync pulse are take a sum to modulo 2. To transfer a Data and a Sync pulse used a pair of wires.

Fig. 2. Manchester – II Code.

Fig. 3. Encoder of Manchester – II Code.

Fig. 4. Decoder of Manchester – II Code.

Fig. 5. Decoder of Manchester – II Code Diagram.

Transfer speeds up to 1 Mbit/sek. (1 MBd).

Circuit of Encoder of Manchester – II Code is a simple (fig.3). Fig.4 - Decoder of Manchester – II Code, fig.5 - the Diagram of Decoder. Admission data are synchronized. The length of code can be: 8-, 16-, 32-bit, etc.

added 23.07.07 19:07:12 | looked over 1681 times