JPH06303170A - Transmitter - Google Patents

Abstract

(57) [Summary] [Object] To provide a transmitter capable of transmitting a signal of a voltage level optimum for reception by a receiver in power line communication without adversely affecting other connected devices. [Structure] The voltage level of the signal extracted from the AC voltage wave of the indoor distribution line 6 by the extracting means 22 is detected by the detecting means 24. The control means 26 compares the detected voltage level with the reference level stored in the storage means 28, and outputs a control signal based on the result. After changing the voltage level of the signal generated by the signal generating means 12 according to the content of the control signal by the level changing means 16, the injection means 1
8 is injected into the AC voltage wave of the indoor distribution line 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter used for power line communication using an indoor distribution line or the like.

[0002]

2. Description of the Related Art In a conventional transmitter used for power line communication using an indoor distribution line or the like, a signal is transmitted at a constant voltage level determined by the sensitivity of the receiver and injected into an AC voltage wave of the power line. .

[0003]

However, in addition to the receiver, various electric appliances are connected to the indoor distribution line, and the impedance characteristics of the indoor distribution line change depending on the operating conditions of these electric appliances. Therefore, even if the signal is sent at a constant voltage level, if the indoor distribution line has low impedance, the voltage level of the signal injected into the AC voltage wave will be low, and the receiver may not be able to receive the signal. It was On the other hand, if the voltage level is set to be high and the signal is transmitted, there is a possibility that the electric appliances connected to the indoor distribution line may be adversely affected when the indoor distribution line has high impedance.

The present invention has been made based on the above circumstances, and even if the impedance characteristic of the power line changes, a signal having an optimum voltage level for the receiver to receive without adversely affecting other connected devices is provided. It is an object to provide a transmitter that can send out.

[0005]

In order to achieve the above-mentioned object, a transmitter according to a first aspect of the present invention provides a signal generating means for generating a signal to be transmitted and a voltage level of the signal generated by the signal generating means. Level changing means for changing, injection means for injecting a signal whose voltage level is changed by the level changing means into an AC voltage wave of the power line, and extraction means for extracting the signal injected by the injecting means from the AC voltage wave of the power line ,
The detection means for detecting the voltage level of the signal extracted by the extraction means, the storage means for storing the reference level which is the voltage level of the signal desired to be received by the receiver, and the voltage level detected by the detection means are The voltage level of the signal injected into the AC voltage wave of the power line is increased when the voltage level is lower than the reference level stored in the storage means, and the AC voltage of the power line is changed when the voltage level detected by the detection means is higher than the reference level stored in the storage means. The control means controls the level changing means so as to lower the voltage level of the signal injected into the voltage wave.

The transmitter according to the invention of claim 2 is the transmitter of claim 1.
In the invention described above, the level changing means changes the voltage level of the signal generated by the signal generating means stepwise, and the control means stores the voltage level detected by the detecting means in the storage means. When the voltage level is lower than the stored reference level, the voltage level of the signal injected into the AC voltage wave of the power line is increased by one step, and when the voltage level detected by the detection means is higher than the reference level stored in the storage means, the AC voltage of the power line is increased. It is characterized in that the level changing means is controlled so that the voltage level of the signal injected into the wave is lowered by one step.

The transmitter according to the invention of claim 3 is the transmitter of claim 1.
Alternatively, the invention described in 2 is characterized in that the voltage level is at a peak time.

According to the invention of claim 4, in the invention of claim 1, 2 or 3, the reference level is
It is characterized by having a certain range.

[0009]

In the transmitter according to the first aspect of the invention, the signal injected by the injecting means by the extracting means is extracted from the AC voltage wave of the power line, and the detecting means detects the voltage level of the signal extracted by the extracting means, When the voltage level detected by the detection means by the control means is lower than the reference level stored in the storage means, the voltage level of the signal injected into the AC voltage wave of the power line is increased, and the voltage level detected by the detection means is stored in the storage means. The level changing means is controlled to lower the voltage level of the signal injected into the AC voltage wave of the power line when the voltage level is higher than the reference level stored in, and the voltage level of the signal injected into the AC voltage wave of the power line is changed by the level changing means. Because it is changed, even if the impedance characteristic of the power line changes, the receiver can receive it without adversely affecting other devices connected to the power line. Capable of delivering the optimal voltage level of the signal to.

The transmitter according to the invention of claim 2 is the transmitter of claim 1.
In the invention described above, when the voltage level detected by the detection means by the control means is lower than the reference level stored in the storage means, the voltage level of the signal injected into the AC voltage wave of the power line is increased by one step, and the detection means is used. When the detected voltage level is higher than the reference level stored in the storage means, the level changing means is controlled to lower the voltage level of the signal injected into the AC voltage wave of the power line by one level, and the level changing means controls the AC of the power line. The voltage level of the signal injected into the voltage wave is changed stepwise, and
The same operation as the described invention is achieved.

The transmitter of the invention described in claim 3 is the transmitter according to claim 1.
Alternatively, in the invention described in claim 2, the voltage level is at a peak, and the same operation as the invention described in claim 1 is achieved.

According to a fourth aspect of the present invention, there is provided the transmitter according to the first, second or third aspect, wherein the reference level has a constant range, and a voltage of a signal injected into an AC voltage wave of a power line. You can stabilize the level.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram of a transmitter which is an embodiment of the present invention.

The transmitter 1 includes a signal generating means 12 for generating an analog signal to be transmitted, a level changing means 16, and an analog signal for the AC voltage wave (AC100) of the indoor distribution line 6.
V, 50 Hz or 60 Hz) injection means 18
An extracting means 22 for extracting an analog signal from the AC voltage wave of the indoor distribution line 6, a detecting means 24 for detecting a peak voltage level of the analog signal, a storing means 28 for storing a reference level, and a controlling means 26. It is configured with.

The signal generating means 12 includes a digital signal transmitting section 13 for generating a digital signal and a digital signal transmitting section 1.
And a D / A conversion unit 14 for converting the digital signal generated in 3 into an FM-modulated analog signal.

The level changing means 16 includes control signals Sa and S.
The voltage level of the analog signal is changed stepwise in 10 steps (L1 to L10) according to the content of b. When only the control signal Sa is ON, the voltage level is raised by one step and the control signal S
When only b is ON, it is lowered by one step. In addition, the control signal S
When both a and Sb are ON, the voltage level is not changed, and when both are OFF, the voltage level is changed to the L1 level. still,
The variable range of the voltage level, that is, the potential difference between the highest L10 level and the lowest L1 level is determined in consideration of the impedance characteristic of the indoor distribution line 6 that changes depending on the operating conditions of the electrical appliances 4 and 5.

The control means 26 outputs control signals Sa and Sb. When the peak voltage level detected by the detection means 24 is lower than the reference level stored in the storage means 28, only the control signal Sa is turned on, when it is high, only the control signal Sb is turned on, and when it is within the reference level range. Both the control signals Sa and Sb are turned on. Further, at the start of the operation of the transmitter 1, both the control signals Sa and Sb are turned off.

The injection means 18 is constructed by connecting a capacitor and an inductor in series, for example. Extraction means 2
2 is a filter circuit including, for example, a capacitor and a resistor. The reference level stored in the storage means 28 is a peak voltage level of an analog signal that can be received by the receiver 3 and does not adversely affect the electric appliances 4 and 5, and has a certain width.

The receiver 3 receives the analog signal sent by the transmitter 1 into the AC voltage wave of the indoor distribution line 6.
In addition to the transmitter 1 and the receiver 3, the electrical appliances 4 and 5 are connected to the indoor distribution line 6.

Next, the operation of the transmitter 1 according to this embodiment will be described. First, the digital signal transmitting unit 13 generates information to be transmitted to the receiver 3 as a digital signal. The digital signal is converted into an FM-modulated analog signal by the D / A converter 14, and then the level changing unit 16 changes the voltage level according to the contents of the control signals Sa and Sb output by the control unit 26. At the start of operation of the transmitter 1, the control means 26 turns off both the control signals Sa and Sb,
As a result, the level changing unit 16 changes the voltage level of the analog signal injected into the AC voltage wave of the indoor distribution line 6 to the lowest L1 level. This is to prevent the electric appliances 4 and 5 connected to the indoor distribution line 6 from being adversely affected. After that, the analog signal whose voltage level is changed to the lowest L1 level is injected into the AC voltage wave of the indoor distribution line 6 by the injection means 18.

Next, the distribution line 6 for indoor use is extracted by the extracting means 22.
Of the analog signal injected into the AC voltage wave of the detector, and the peak voltage level of the extracted analog signal is detected by the detecting means 24.
To detect. The control means 26 compares the detected peak voltage level with the reference level stored in the storage means 28, and outputs a control signal based on the result.

When the peak voltage level detected by the detection means 24 is lower than the reference level stored in the storage means 28, only the control signal Sa is turned on, whereby the level changing means 16 changes the AC voltage wave of the indoor distribution line 6 into an AC voltage wave. Raise the voltage level of the injected analog signal by one step. The peak voltage level detected by the detection means 24 is stored in the storage means 28.
The level changing means 16 outputs the voltage of the analog signal to be injected into the AC voltage wave of the indoor distribution line 6 until it falls within the range of the reference level stored in the above, that is, until the control means 26 turns ON both the control signals Sa and Sb. Level up in stages.

When the control means 26 turns on both the control signals Sa and Sb, the level changing means 16 does not change the voltage level. Therefore, the analog signal having a constant voltage level is continuously injected into the AC voltage wave of the indoor distribution line 6.

The peak voltage level detected by the detection means 24 becomes lower than the reference level stored in the storage means 28 because the operating characteristics of the electric appliances 4, 5 change and the impedance characteristic of the indoor distribution line 6 changes. In this case, the control means 26 turns on only the control signal Sa, whereby the level changing means 16 raises the voltage level of the analog signal injected into the AC voltage wave of the indoor distribution line 6 by one step. When the peak voltage level detected by the detection means 24 becomes higher than the reference level stored in the storage means 28, the control means 26 turns on only the control signal Sb, whereby the level changing means 16 causes the indoor distribution line 6 to operate. The voltage level of the analog signal injected into the AC voltage wave is lowered by one step. Then, until the peak voltage level detected by the detection means 24 falls within the range of the reference level stored in the storage means 28, that is, until the control means 26 turns ON both the control signals Sa and Sb, the level changing means 16 keeps indoors. The voltage level of the analog signal injected into the AC voltage wave of the distribution line 6 is changed stepwise.

According to this embodiment described above, the analog signal injected by the injection means 18 by the extraction means 22 is extracted from the AC voltage wave of the indoor distribution line 6, and the analog signal extracted by the extraction means 22 by the detection means 24. Of the analog signal to be injected into the AC voltage wave of the indoor distribution line 6 when the voltage level detected by the detection means 24 by the control means 26 is lower than the reference level stored in the storage means 28. When the voltage level detected by the detection means 24 is higher than the reference level stored in the storage means 28, the level changing means 16 is controlled to lower the voltage level of the analog signal injected into the AC voltage wave of the indoor distribution line 6. However, the level changing means 16 changes the voltage level of the analog signal to be injected into the AC voltage wave of the indoor distribution line 6, so that the electric appliances 4, 5 Even when the production situation changes and the impedance characteristics of the indoor distribution line 6 change, it is possible to send out a signal of an optimum voltage level for the receiver 3 to receive without adversely affecting the electric appliances 4 and 5. it can.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the gist thereof. For example, in the above embodiment, the level changing means 16
In the above, the voltage level of the analog signal is stepwise changed in 10 steps (L1 to L10) according to the contents of the control signals Sa and Sb, but it is stepwise changed in 10 steps or more for fine control. It may be one that is changed steplessly.

Further, in the above embodiment, the level changing means 16 injects into the AC voltage wave of the indoor distribution line 6 when the control signals Sa and Sb are both OFF, that is, when the operation of the transmitter 1 is started. The voltage level of the signal is changed to the lowest L1 level, but in order to quickly bring the peak voltage level of the analog signal extracted by the extraction means 22 into the range of the reference level stored in the storage means 28, the voltage level is set to approximately the middle. It may be changed to the L5 level which is located, or may be changed to the voltage level of the analog signal injected into the AC voltage wave of the indoor distribution line 6 at the time of the previous transmission.

Further, in the above embodiment, the FM modulated analog signal is injected into the AC voltage wave of the indoor distribution line 6, but some signal is injected into the AC voltage wave of the power line to which the AC voltage is applied. Anything will do.

[0029]

As described above, according to the invention described in claim 1, the signal injected by the injecting means by the extracting means is extracted from the AC voltage wave of the power line, and the signal extracted by the extracting means is detected by the detecting means. The voltage level is detected, and when the voltage level detected by the detection means by the control means is lower than the reference level stored in the storage means, the voltage level of the signal injected into the AC voltage wave of the power line is increased, and the detection means detects the voltage level. When the voltage level is higher than the reference level stored in the storage means, the level changing means is controlled to lower the voltage level of the signal injected into the AC voltage wave of the power line, and the level changing means injects into the AC voltage wave of the power line. Because the voltage level of the signal to be changed is changed, even if the impedance characteristic of the power line changes, other devices connected to the power line are adversely affected. It is possible to provide a transmitter capable of sending an optimum voltage level of the signal to the receiver is received without the.

According to the invention of claim 2, in the invention of claim 1, when the voltage level detected by the detection means by the control means is lower than the reference level stored in the storage means, an AC voltage wave of the power line is obtained. The voltage level of the signal to be injected into the AC voltage wave of the power line is decreased by one step when the voltage level detected by the detection means is higher than the reference level stored in the storage means. The level change means is controlled to change the voltage level of the signal injected into the AC voltage wave of the power line stepwise by the level change means, and a transmitter having the same effect as the invention according to claim 1 is provided. Can be provided.

According to a third aspect of the invention, there is provided a transmitter according to the first or second aspect of the invention, wherein the voltage level is at a peak time and has the same effect as the invention of the first aspect. can do.

According to a fourth aspect of the present invention, there is provided the transmitter according to the first, second or third aspect, wherein the reference level has a certain range, and the voltage of a signal injected into an AC voltage wave of a power line. A transmitter capable of stabilizing the level can be provided.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a transmitter that is an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 transmitter 3 receiver 4, 5 electric appliance 6 indoor distribution line 12 signal generating means 13 digital signal generating section 14 D / A converting section 16 level changing means 18 injection means 22 extracting means 24 detecting means 26 control means 28 storage means

Claims (4)

[Claims] 1. A signal generating means for generating a signal to be transmitted, a level changing means for changing a voltage level of a signal generated by the signal generating means, and a signal whose voltage level is changed by the level changing means for alternating current of a power line. Injection means for injecting into the voltage wave, extraction means for extracting the signal injected by the injection means from the AC voltage wave of the power line, detection means for detecting the voltage level of the signal extracted by the extraction means, and receiver Storage means for storing a reference level which is a voltage level of a signal desired to operate, and a signal to be injected into an AC voltage wave of the power line when the voltage level detected by the detection means is lower than the reference level stored in the storage means. Increase the voltage level and inject it into the AC voltage wave of the power line when the voltage level detected by the detection means is higher than the reference level stored in the storage means. Control means for controlling the level changing means so as to lower the voltage level of the signal to be transmitted. 2. The level changing means changes the voltage level of the signal generated by the signal generating means stepwise, and the control means stores the voltage level detected by the detecting means in the storage means. When the voltage level is lower than the stored reference level, the voltage level of the signal injected into the AC voltage wave of the power line is increased by one step, and when the voltage level detected by the detection means is higher than the reference level stored in the storage means, the AC voltage of the power line is increased. 2. The transmitter according to claim 1, wherein the transmitter is control means for controlling the level changing means so as to lower the voltage level of the signal injected into the wave by one step. 3. The transmitter according to claim 1, wherein the voltage level is a peak level. 4. The transmitter according to claim 1, wherein the reference level has a certain range.