JPS61280724A - Receiving section of power line transporting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a receiving section of a power line carrier device.

2. Description of the Related Art FIG. 6 shows a circuit block diagram of a receiving section of a power line carrier device using a conventional amplitude modulation method. In FIG. 6, 1 and 2 are a receiving section and a control section, respectively. 3 is a resonant circuit, which is coupled to a power line 8 connected to a commercial power source 7;
The commercial frequency component of the commercial power source 7 is removed to extract a signal with a desired carrier frequency. 4 is an amplifier circuit that amplifies the carrier high frequency detected by the resonant circuit filter to a required voltage. A demodulation circuit 11 demodulates a digital signal from a high frequency carrier. Reference numeral 5 denotes a power synchronization circuit, which is used to detect the zero-crossing point of the commercial power supply 7 and determine the timing for decoding the digital signal.The digital signal demodulated by the receiver 1 is decoded by the control unit 2. , processing such as controlling a load (not shown) and changing the display is performed according to the content of the digital signal.

Problems to be Solved by the Invention However, there is a possibility that various noise sources may be connected to the commercial power supply 7, and the environment is extremely inappropriate for using the power line 8 as a transmission path for high-frequency signals. be. In order to perform highly reliable transmission under such an environment, it is necessary to increase the frequency selectivity of the receiving section 1 to improve the noise and signal discrimination performance. However, the conventional receiving section 1
The frequency selectivity depends on the performance of the resonant circuit 5.

In the conventional example, it was difficult to obtain high frequency selectivity.

In order to solve this problem, it is effective to provide a plurality of resonant circuits in the receiving section, but there is a problem in that the number of two parts increases significantly. Generally, the frequency modulation method can provide higher quality transmission than the amplitude modulation method, but the number of parts per unit increases significantly or expensive parts are required.

Means for Solving the Problems The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a receiving section of a power line transport device that has higher transmission reliability with the same number of parts or fewer parts than the conventional one. This is what we provide. Therefore, a counter is provided in the receiving section to count the rising edge or falling edge of the output voltage of the amplifier circuit, and the frequency is discriminated based on the counter value.

Effect By doing this, the frequency can be determined based on the counter value of the counter.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram relating to the receiving section of this embodiment. In FIG. 1, 6 is a counter, 9 is a counter output of counter B, and 10 is a reset input of counter 6. Portions with other symbols are the same as in the conventional example, and their explanation will be omitted. FIG. 2 shows the waveforms of each part of the receiving section 1.
a indicates the input signal of the resonant circuit B, b indicates the output signal of the synchronous circuit 5, and C indicates the output signal of the amplifier circuit 4, respectively. In this embodiment, a 1-bit signal is transmitted every half cycle of the commercial power supply 7, and when the carrier frequency is 120-Hz, the logic is ``1'', and when the carrier frequency is 100 kHz, the logic is 10''. Therefore, in the case of Figure 2, IQll
It is in a state where information of Q is being transmitted.

Next, the operation of this embodiment will be explained.

Resonant circuit 6. Amplification circuit 4. The operation of the power supply synchronization circuit 5 is the same as the conventional one. The counter 6 counts the rising edges or falling edges of the output voltage of the amplifier circuit 4 and outputs the count value of the counter B from the counter output 9.

The output counter 60 count value is reset manually 1
Cleared to zero. The control unit 2 decodes the digital signal from the power synchronization circuit 5 and clears the count value of the counter 6 to zero every time a synchronization pulse is detected, and after a certain period of time, the counter output 9 outputs the count value of the sales counter 6. go read.

Based on the count value, it is determined whether or not there is a high frequency carrier. Now, assuming that the timing at which the control section 2 reads the count value is 5 ms after the detection of the synchronization pulse, the count value read by the control section 2 will be 500 when the carrier frequency is 100 Kl-1z. Therefore, when the count value is 500±25 in the control unit 2, the logic is 20", and the count value is 600±25.
If it is determined that the logic is ``1'' when the value is 25.

The frequencies of ioo±5KHz and 120±5KH2 are discriminated.

Furthermore, if a microconbeater with a built-in counter is used in the control section 2, the number of parts can be further reduced.

Effects of the Invention According to the present invention, since the frequency is discriminated by counting the rising edge or falling edge of the output voltage of the amplifier circuit with a counter provided in the receiving section, the frequency can be determined by the counter (directly). By doing so, frequency selectivity can be increased with the same or fewer number of parts as in the past, and a receiving section of a power line carrier device with improved transmission reliability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram related to a receiving section of a power line carrier device according to an embodiment of the present invention, and FIG. 2 is a waveform diagram of each part of the same,
FIG. 6 is a block diagram of the conventional circuit. ro...resonant circuit, 4...amplification circuit. 5...Power synchronization circuit, 6...Counter. 7...Commercial power supply, 8...Power line.

Claims (1)

[Claims] A power line (8) is used in a receiving section of a power line carrier device that transmits a carrier high frequency frequency modulated digital signal synchronized with the zero crossing point of a commercial power source by superimposing it on a power line of a commercial power source, and receives this carrier high frequency wave at a receiving section. a resonant circuit (3) coupled to the power line (8) to detect the carrier high frequency on the power line (8); an amplifier circuit (4) that amplifies the carrier high frequency detected by the resonant circuit (3) to a required voltage level; A receiving section of a power line carrier device includes a counter (6) that counts rising edges or falling edges of an output voltage of an amplifier circuit (4), and a power synchronization circuit (5) that detects a zero-crossing point of a commercial power source.