| 摘要 |
PURPOSE:To obtain a delay detection-system phase demodulator circuit which is stable against temperatures. CONSTITUTION:The input from terminal 101 is branched by 1, and one is branched furthermore by 2, and the other is delayed 4 by 1 bit and is branched 3 through voltage control phase shifter circuit 10. One is subjected to phase detection 6, and the other is subjected to phase detection 7 after 90 deg. phase shift 5 to output signals corresponding to phase difference, and these signals are discriminated 8, 9 to demodulate a prescribed digital signal string. Now, if phase phi exists between inputs of branching circuits 2 and 3, signals A and B based on this phase and signals C and D from discrimination circuits 8 and 9 are inputted to detection circuit 11 to generate a positive or negative voltage according to the polarity of phase slippage, and circuit 10 is controlled by this voltage to correct phase shift fluctuation of delay circuit 4. Thus, it is unnecessary that a considerably severe stability against temperatures is required for the delay circuit. |
