SK5537Y1 - Method for amplitude modulation for purpose of information transmission in power line 230V a device for thereof - Google Patents

Abstract

Amplitude modulation of the AC voltage is used for wireless transmission of information. It is expected to use mainly at external and internal lighting, wherever it is necessary to manage the intensity of light and where it is not possible to install additional wiring control lines. The solution lies in an appropriate amplitude modulation of power supply and following demodulating, whereby voltage also serves as power supply.

Description

SK 5537 Υ1

Technical field

The technical solution concerns switchboards, power lines, appliances and communication between them through a common mains supply. It is mainly the regulation of the light intensity without the use of a control line.

BACKGROUND OF THE INVENTION

Currently, a modulated higher frequency solution superimposed on the mains voltage is used to transmit information.

The disadvantage of this solution is that higher superimposed frequencies require quality power distribution. Furthermore, they require defined electrical separation by resonant circuits. The return communication between the appliance and the source is complicated and feasible only at higher cost. Another solution consists in a separate management line.

The essence of the technical solution

The essence of the technical solution lies in the amplitude modulation and demodulation of the supply voltage. A modulator is located in the electrical switchboard from where the power line is routed. It changes the amplitude of the output supply voltage according to the selected protocol synchronously with the network frequency. The number of amplitude modulation levels may vary. Preferably two levels are used for this purpose. Original and reduced by about 5%. The bit word is a combination of reduced and unreduced supply voltage half-periods with a finite, defined number. Only one half period is modulated. Positive or negative. The second half-period is unchanged and serves as a reference for the evaluation circuit on the appliance side. Reference is needed due to fluctuations in supply voltage. Let's choose a negative half-period and a data positive. The evaluation circuit compares these half-periods. It always checks each negative and immediately compares the following positive. If they are the same nothing happens. If negative is followed by a reduced positive, the register is started with a defined number of bit places. In the case of an eight bit word, it will be eight places. The positive half-period after the registry is started is assigned levels as follows: the same positive half-period has a logical zero level and the lowered half-period has a logical unit level. When the register is filled, whose clock frequency is synchronized by the mains voltage, the data is forwarded to the processing and operation, for example to reduce the intensity of the light source. The bitword may have different lengths and may contain different instructions. The value that preceded the start of the register may be used as the mains voltage reference.

Amplitude modulation and demodulation with a reference voltage value comparison have higher fault tolerance.

Such a method of communication is useful for regulating the lighting, either internal or external. No additional guidance is required. After the power line, this information reliably gets to the right place.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 is a schematic circuit diagram of amplitude modulation for information transmission over a power supply line. In FIG. 2, FIG. 3, FIG. 4 shows possible methods of amplitude modulation and information evaluation.

Examples of technical solution

The circuitry for performing the amplitude modulation method of FIG. 1 consists of a modulator block 1, a demodulator block 2, a power control unit 3, an appliance block 4, wherein the power control unit 3 and the appliance block 4 are interconnected. The modulator block 1 is connected to the demodulator block 2 by a line 5.

In FIG. 2, one possible modulation and demodulation method is shown. In this case, the modulator only affects the positive half-period. This carries an instruction about the value of the information. Two-state modulation is used. If the peak value of the positive half-period is the same as the value of the negative-reference half-period, it means logic 0 for the evaluation circuit. If the peak value of the positive half-period is reduced it means logical 1. The positive half-period value is always compared with the previous negative-reference

SK 5537 Υ1 dou. If the demodulator identifies a reduced positive half-period, the record is automatically triggered. It records and saves data in the count of 18. The running of the register is clocked by the network frequency. After reading the necessary number of data, the register transfers the stored data for processing. The decoding circuit evaluates the incoming series of logic zeros and units and transmits it to the power control unit.

PROTECTION REQUIREMENTS

Claims (12)

Wiring for performing amplitude modulation for the purpose of transmitting information in a 230V power line, characterized in that it consists of a modulator block (1), a demodulator block (2) interconnected by a power line (5), with the demodulator block (2) is connected to the block (3) by a power control unit connected to the block (4) of the appliance. Connection for performing amplitude modulation according to claim 1, characterized in that the demodulator block (2) is connected to a switching or regulating unit of the appliance. 3. A method for amplitude modulation of a 230 V supply voltage in a line, characterized in that the amplitude of the output voltage from the modulator block (1) is achieved such that the modulator limits the amplitude of the supply voltage by a level proportional to the modulation depth voltage wherein the amplitude is limited according to the transmitted instruction. A method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the frequency of the mains voltage is used as a synchronization for the transmission of information. The method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the demodulator block (2) for detection uses a peak value of the supply voltage half-period amplitude as a reference value. A method for amplifying modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the demodulator block (2) for detection uses the peak amplitude of the opposite polarity supply voltage half-period as the information carrier. A method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, wherein multiple supply voltage periods are used to transmit the instruction. A method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the modulation depth is less than the permissible variation in the mains supply voltage. A method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the clock frequency of the modulation is synchronized with the mains frequency. Method for amplitude modulation of a 230 V supply voltage in a line according to claim 3, characterized in that the demodulator block (2) is synchronized by the mains frequency. The amplitude modulation method of a 230 V supply voltage in a line according to claim 3, wherein the demodulation process begins with a first half period, the value of which differs from the reference value of the previous half period and ends with the evaluation of a specified number of half periods. 12. The method of amplitude modulation of a 230 V supply voltage in a line according to claim 3, wherein the information evaluation process consists of two steps, namely demodulating and decoding the demodulated signal. 4 drawings