Abstract
We had been developed the biotelemetry system for recording neural signals and other biological signals. In this time, we improved the modulation and demodulation circuits to receive high frequency pulse train about 50kHz. Generally, at the radio, carrier frequency deviation is decided by the manual. Therefore, it is difficult to find the system, which has high-speed response.However, bio-telemeter required more high-speed modulation for more biological information. Then, we also improved the IF (intermediate frequency) amplifier, able to amplified the high-frequency modulated pulse train.This system has employed FM-PWM (frequency modulation- pulse width modulation) method, because of the stability and reliability. Multiple input and multi-sampling rate theory could transmit the neural signals (high frequency) and other data (low and lower frequency) in simultaneously. The output signal of IFT (end stage of FM Front End) is directly decoupled to the next IF amplifier with LC elements. In the IF amplifier, employed the LC coupling instead of the ceramic filter, to spread the band pass. Two TA7302 are used for the IF amplifier. TA7031P was used for the discriminator. At the results, this improved system could transmit the data by above-mentioned theory, and clearly demodulated the 50kHz pulse train at the receiver. [J Physiol Sci. 2008;58 Suppl:S99]
