Code identification recovery device for gmsk modulation wave

Abstract

Abstract PURPOSE:To avoid the circuit scale from being increased by applying a signal after frequency detection of a GMSK modulation wave to one input terminal, applying an output of a threshold level supply circuit to the other input terminal, comparing the signal with the output of the threshold level supply circuit and using a code adjacent point as a discrimination point when there is a tight band limit at a sender side. CONSTITUTION:The device consists of a comparator 1, a threshold level supply circuit 2, and a latch means 3 such as a D flip-flop, and a signal resulting from frequency-detection of a GMSK modulation wave is inputted to a noninverting terminal 1 of the comparator 10 and a threshold voltage of the threshold level supply circuit 2 is fed to an inverting input terminal. When the signal resulting from frequencydetection of a GMSK modulation wave is inputted to the noninverting terminal 10 of the comparator 1, the signal is identified in response to the threshold voltage, sampled by a recovery clock, latched in the latch means 3 and outputted in a recovery code of the data from a terminal 20. Thus, the simple circuit constitution not needing plural comparators and complicated logic circuits is realized.

Inventors

• 👤 Takashi Matsumura
• 👤 隆司 松村

Bibliographic Details