| 摘要 |
PURPOSE:To attain digital IC-implementation by composing a carrier detecting circuit of a Schmitt circuit, differentiating circuit, counter, and clock generator. CONSTITUTION:An input carrier signal (e) is inputted to the Schmitt circuit 7. The Schmitt circuit 7 has hysteresis characteristics of the threshold value switched by a control input to have + or -V3 when the control input is 1 or + or -V4 when 0. The control input to the circuit 7 is the output (i) of the detecting circuit, and a shaped waveform (f) appears at the output of the circuit 7. The waveform (f) is differentiated by the differentiating circuit 8, whose output (g) is applied to the reset terminal R of the counter 9. The counter 9 counts clock pulses from the clock generator 11 and is reset before attaining to a specific value, so the carrier detection signal (i) appears at its output terminal 10. |
