JPH03145355A - Pm wave demodulation circuit - Google Patents

Abstract

PURPOSE:To eliminate the need for a phase detection circuit and to simply constitute a PM wave modulation circuit by outputting a Manchester modulation signal from a comparator and a flip-flop. CONSTITUTION:First and 2nd comparators A2, A3 compare positive and negative PM wave inputs (a) based on positive and negative reference voltages VT1, VT2 respectively to obtain outputs b, c, which set/reset a flip-flop F1, then an output (d) is obtained. Thus, the digital signal output (d) is a Manchester modulation output and a demodulation digital signal is obtained by using a timing extraction circuit D1 and an identification circuit A6. Thus, the PM wave demodulation circuit with simple constitution not requiring a phase detection circuit is realized.

Description

[Detailed description of the invention] A. Industrial application field The present invention relates to a PM wave demodulation circuit.

B0 Summary of the Invention The present invention provides a P~1 wave demodulation circuit which obtains a Manchester modulated output from a PM wave and uses a timing wave extraction circuit and an identification reproducing circuit to obtain a demodulated digital signal. , the first PM wave adult horn positive and negative inputs are compared with positive and negative reference voltages, respectively. The output is obtained from a second comparator and a flip-flop to which the respective outputs of the first and second comparators are input.

C1 Conventional technology Conventionally, i! PMtl! As the demodulation circuit, a synchronous detection demodulation circuit or a delayed detection demodulation circuit shown in FIG. 5 or 6 is used.

These demodulation circuits obtain a Manchester modulated wave from a phase detection circuit 1 and a carrier wave regeneration circuit 2 or a time slot delay circuit 3, and obtain a demodulated JA1 digital signal from a timing wave extraction circuit 4 and an identification regeneration circuit 5. ing.

D1 Problems that the invention is intended to solveHowever, the above-mentioned conventional PM wave demodulation circuit uses a phase detection circuit, and what is the circuit configuration? There was a drawback that it became Bi.

The present invention has been made in view of these conventional problems, and its purpose is to provide a simple PM wave demodulation circuit that does not require a phase detection circuit.

81 Means for Solving the Problems In order to achieve the above object, the PM wave demodulation circuit of the present invention obtains a PM wave input signal, a Manchester modulation output, and demodulates the signal using a timing wave extraction circuit and an identification/regeneration circuit. In the apparatus for obtaining a signal, the Manchester modulation output is compared with the positive and negative inputs of the PM wave input with the positive and negative reference voltages, respectively. a second comparator; The outputs of the second comparators are obtained from input flip-flops.

F1 action 1st. When the second comparator compares the positive and negative inputs of the PM wave with the positive and negative reference voltages VT1 and VT2, respectively, as shown in FIG. 2, the outputs S and C shown in FIG. 2 are obtained. If the flip-flops are set and reset by these outputs S and C, the output D shown in FIG. 2 is obtained.

Therefore, since this digital signal output d is a Manchester modulated output, a demodulated digital signal can be obtained using a timing wave extraction circuit and an identification circuit.

G. Example Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a PM wave demodulation circuit, and FIG. 2 shows waveforms of various parts of the circuit shown in FIG.

In Fig. 1, l\1 is a preamplifier with a PVI wave input wave width of 1, and A2 is a comparator that inverts and compares the inverted output of the PM wave input a from amplifiers l to l with the basic voltage VTI. , A3 is a comparator that inverts the inverted output of PM wave input 1 from amplifier AI and compares it with reference voltage VT2. A4 and A5 are inverters that invert the outputs S and C of comparators A2 and A3, respectively. Fl is an inverter. The outputs of A4 and A5 are input to the S and R terminals of a flip-flop, DI is a clock extraction circuit that extracts the clock e from the output C of the flip-flop Fl, and 80 is the output d of the flip-flop Fl and the clock extraction circuit DI.
This is an EXOR circuit which manually inputs the extracted clock e and outputs a digital output f.

Next, the operation of this PM wave demodulation circuit will be explained using the chart of FIG. The comparator A2 receives a PM wave input &, the base Q7Ij, and an output from the voltage VTI, and the comparator A3 receives an output C from the PM wave input 1 and the base voltage VT2. Also, flip-flop F! is output from the rising edge of output C to the falling edge of output C, so output d
Output.

The output d is a Manchester modulated deinotal signal. From this output d, an extracted clock e is obtained from the clock extraction circuit DI, and from the output d, EXO as an identification reproducing circuit is obtained.
r (Input 〇 to the circuit.

Therefore, since the EXOR circuit A6 outputs when only one of the output d and the extracted clock e is being output, a demodulated di-notional signal output r is obtained.

Figure 3 shows the case where the frequency of the PM manual input a is doubled, but since the extracted clock e is doubled after this PM large input, demodulation is performed in the same way as in the case of Figure 2. can do.

H1 Effects of the Invention Since the present invention is configured as described above, a Manchester modulation signal can be obtained by a comparator and a flip-flop, and a phase detection circuit with a complicated configuration made of a conventional analog circuit is not required. It can be easily configured into a PM wave modulation circuit.

[Brief Description of the Drawings] Figure 1 is a circuit diagram showing an embodiment of the present invention, Figures 2 and 3 are circuit diagrams showing an embodiment of the present invention.
FIG. 4 is a time chart showing the voltage at the numbered part in FIG. 1, FIG. 4 is a time chart for explaining a conventional example, and FIGS. 5 and 6 are circuit diagrams showing different conventional examples. A4. A3... Comparator, F! ...Flip-flop, DI...timing extraction circuit, A6...E
XOR circuit. ■ Fig. 2 Fig. 8 (c) Eka C National Precept 1 ■ - Koichi・ (e) k″; Tal output f Garden] -・ Fig. 5 Fig. 6

Claims (1)

[Claims] (1) Obtain Manchiesta modulation output from PM wave input,
A demodulated digital signal is obtained by using a timing wave extraction circuit and an identification reproducing circuit, wherein the Manchiesta modulation output is compared with the positive and negative inputs of the PM wave input with the positive and negative reference voltages, respectively. 1. A PM wave demodulation circuit comprising a second comparator and a flip-flop to which the outputs of the first and second comparators are input.