Abstract:

In the transmission of neural control signals to the internal module of a implantable neural-signal acquisition system using the differential coding method,high clock synchronization between the internal and the external systems is required,which makes the circuit design extremely difficult.In order to solve this problem,a new data coding method is presented.In the external module,control signals coded by pulse-width modulation are transmitted to the internal module through binary phase shift keying（BPSK）modulation and demodulation, and the clock detector, clock divider, pulse width counter and pulse logic judger are used to decode the signals. Thus, both the internal and the external modules can work at asynchronous system clock frequencies, and the circuit design and verification are greatly simplified. The new coding method has been successfully applied to a board circuit system for wireless implantable neural-signal acquisition, and the waveform test results verify the feasibility of the method. Moreover, no error has been found in the transmission test of 1 000 000 B random data produced by a M-sequence generator, thus coming to the conclusion that the proposed coding method is highly reliable.

Key words: data coding, pulse-width modulation, neural control signal, wireless transmission, implantable system