JP4876753B2 - Door phone master unit - Google Patents

Description

  The present invention transmits audio, video, and control signals between the slave unit and the extension master unit, and includes a band-pass filter to transmit the control signal separately from the audio signal and video signal. The present invention relates to a door phone master unit in which a route is formed.

  2. Description of the Related Art Conventionally, as shown in Japanese Patent No. 3726372 (Patent Document 1), a door phone parent device in which a control signal path is formed is known. As shown in FIG. 3, the doorphone master unit A includes a slave unit connection terminal 92 connected to the slave unit B via the transmission line 91 and an extension connection connected to the extension master unit C via the transmission line 91. A pair of terminals 93 are provided, and a control signal path R that connects the slave unit connection terminal 92 and the extension connection terminal 93 is formed in the master unit body. A connection point P to which the control signal receiving circuit 94 and the control signal transmitting circuit 95 are connected is provided on the control signal path R, and a band pass filter is provided between the connection point P and the slave unit connection terminal 92. F is provided.

Therefore, in this case, the control signal can be transmitted between the slave unit B and the extension master unit C separately from the audio signal and the video signal through the control signal path R.
Japanese Patent No. 3726372

  However, in the door phone base unit A which is the conventional example, the audio signal and the video signal transmitted from the side of the additional connection terminal 93 on the control signal path R are transmitted to the connection point P. Therefore, the control signal receiving circuit 94 and the control signal transmitting circuit 95 connected to the connection point P become connection loads, and there is a possibility that the transmitted audio signal and video signal are attenuated.

  The present invention has been invented in view of the above-described background art, and its problem is that in a door phone master unit in which a control signal path for separating and transmitting a control signal from an audio signal or a video signal is formed, An object of the present invention is to provide a door phone master unit in which a connection load in a frequency band other than a transmission band, particularly an audio signal band and a video signal band is reduced.

In order to solve the above-mentioned problems, in the invention according to claim 1 of the present application, a transmission signal including a control signal of a specific frequency band and an audio signal and a video signal of a frequency band different from the frequency band are transferred to the slave unit and the extension parent. Door phone master unit that transmits to / from the unit via a transmission line, connected to one slave unit connection terminal connected to the slave unit via the transmission line, and connected to the extension master unit via another transmission line A plurality of additional connection terminals, a control unit for recognizing and analyzing control signals from the additional master unit and slave units, or newly generating a control signal, and a control signal for transmitting a control signal from the control unit A transmission circuit, a control signal receiving circuit that receives control signals transmitted from the extension master unit and the slave unit, a slave unit power supply unit that supplies power to the slave unit via the transmission line, and a control provided in the master unit body Handset power supply by passing only signal frequency band And a band pass filter that forms a control signal path for blocking the power supply from the main unit to the extension base unit and transmitting the control signal separately from the audio signal and the video signal between the slave unit connection terminal and the extension connection terminal. In the intercom base phone provided, the control signal transmission circuit and the control signal reception circuit are connected to a connection point on the control signal path, and the connection point is a path between the band pass filters and only the control signal passes through. The band-pass filter is provided between the connection point and the slave unit connection terminal and between the connection point and the extension connection terminal on the control signal path.

  Further, in the invention according to claim 2 of the present application, in the doorphone master unit according to claim 1, the control signal path is connected from the slave unit connection terminal to the connection point, and is branched into a plurality of extension connections from the connection point. Each band is connected to the terminal, and one band pass filter is provided between the connection point and the slave unit connection terminal and on all control signal paths connecting the connection point and the plurality of additional connection terminals. It is characterized by being.

  In the doorphone master unit according to claim 1 or 2, the connection point is sandwiched between a plurality of band pass filters on the control signal path, and the signal transmitted from the slave unit connection terminal side and the extension connection terminal side Both the audio signal and the video signal of the transmitted signal are cut by the band pass filter so that they are not transmitted up to the connection point. Therefore, the control signal transmission circuit and the control signal reception circuit connected to the connection point do not become a connection load in a frequency band other than the transmission band of the control signal, particularly in the audio signal band, the video signal band, and the DC power supply band. The attenuation of the transmitted audio signal and video signal can be reduced.

  FIG. 1 shows a doorphone master device A according to an embodiment. This door phone base unit A includes a pair of extension unit connection terminals T1 connected to the extension unit B via the transmission line L1, and three pairs of extension connections connected to the extension base unit C via another transmission line L2. A control unit 45 for recognizing and analyzing control signals from the terminal T2 and the extension master unit C and slave unit B, or generating a new control signal in response to an operation input from the operation button 46, and a control unit 45 A control signal transmission circuit 42 for transmitting a control signal from the control unit, a control signal reception circuit 41 for receiving a control signal transmitted from the extension master unit C and the slave unit B, and power to the slave unit B via the transmission line L1. The power supply unit 5 to be supplied and the base unit main body are allowed to pass only the frequency band of the control signal, thereby preventing the power supply from the slave unit power supply unit 5 to the additional base unit C and sending the control signal to the slave unit B. And the audio signal and video signal are separated between And a band-pass filter F1~F4 forming the feed causes the control signal path R1 to R4.

  The control signal transmitting circuit 42 and the control signal receiving circuit 41 are connected to the connection point P on the control signal paths R1 to R4, and the band pass filters F1 to F4 are connected to the connection point P on the control signal paths R1 to R4. It is provided between the slave unit connection terminal T1 and between the connection point P and the extension connection terminal T2.

  Specifically, the control signal paths R1 to R4 are connected to the connection point P from the slave unit connection terminal T1, and are branched into a plurality from the connection point P and connected to each additional connection terminal T2 one path at a time. Yes, one band-pass filter F1 to F4 is provided on each of the control signal paths R1 to R4 between the connection point P and the slave unit connection terminal T1 and on all the connection points P1 and the plurality of additional connection terminals T2. It has been.

  Hereinafter, the doorphone master unit A of this embodiment will be described in more detail. As shown in FIG. 1, this doorphone master unit A transmits video, audio, and control signals between each unit by connecting the slave unit B and the extension master unit C via transmission lines L1 and L2. It becomes a part of the door phone system. Further, this door phone master unit A is provided with three pairs of extension connection terminals T2, and divided into three pairs of extension connection terminals T2, four extension master units C are connected via a transmission line L2. Yes. A two-wire balanced cable is used for the transmission lines L1 and L2.

  The handset B is normally installed outdoors, and includes a camera (not shown) for imaging a visitor, a microphone (not shown) for calling, and a speaker (not shown). Operating with power supplied from A. The video signal output from the camera and the audio signal output from the microphone are transmitted to the doorphone master unit A via the transmission line L1. On the other hand, the audio signal transmitted from the doorphone master unit A and the extension master unit C is output by a speaker.

  The exposure of the camera, the focus, the volume of the microphone, etc. can be adjusted. These adjustments are performed in response to a control signal from the doorphone master unit A or the extension master unit C. The adjustment state of the camera, microphone, etc. is transmitted to the doorphone master unit A and the extension master unit C as control signals.

  As shown in FIG. 1, the intercom base A has a handset connection terminal T1. A transmission line L1 from the handset B is connected to the handset connection terminal T1, and a signal input from the handset B is received. The signal is transmitted to the demultiplexing circuit 1a and the control signal path R1 provided in the intercom base A. Here, since the transmission lines L1 and L2 are two-wire balanced cables and are used for transmission of video signals, audio signals, and control signals and supply of power, the transmission lines L1 and L2 have video signals, Audio signals and control signals are mixed, and these signals are transmitted superimposed on the power supply. Since the video signal, the audio signal, and the control signal have different frequency bands (see FIG. 2), the signal input from the transmission line L1 through the slave unit connection terminal T1 is separated by frequency band in the demultiplexing circuit 1a of the doorphone master unit A. By separating, the video signal and the audio signal are separated, and the control signal is further separated by the band pass filter F1.

  In addition, the doorphone master unit A includes a monitor 22 for displaying an image captured by the camera of the slave unit B, and further includes a microphone 33 and a speaker 35 to enable a call with the slave unit B. I have. A CRT or a liquid crystal display is used for the monitor 22.

  The video signal separated by the demultiplexing circuit 1 a is demodulated by the video demodulation circuit 21 and then input to the monitor 22, and an image captured by the camera of the slave unit B is displayed on the monitor 22. The audio signal separated by the demultiplexing circuit 1 a is amplified by being input to the speaker amplifier 34 through the 2-wire-4 wire conversion circuit 31, and the speaker 35 is driven by the output of the speaker amplifier 34. The audio signal from the microphone 33 is amplified by the microphone amplifier 32 and input to the demultiplexing circuit 1 a through the 2-wire-4 wire conversion circuit 31.

  Further, the signal input from the slave unit B is transmitted to the control signal path R1 separately from the demultiplexing circuit 1. In the control signal path R1, bandpass filters F1 to F4 are inserted between the slave unit connection terminal T1 and the connection point P and between the connection point P and the extension connection terminal T2. The band-pass filters F1 to F4 use a general filter using an LCR circuit composed of a series and parallel combination based on an inductor L, a capacitor C, and a resistor R, and are controlled by control signal paths R1 to R4. Only the frequency band of the signal is allowed to pass. A control signal receiving circuit 41 and a control signal transmitting circuit 42 are connected to the connection point P, and connected to a control unit 45 including a CPU via a control signal demodulating circuit 43 and a control signal modulating circuit 42.

  Accordingly, the signal input from the handset B is cut by the band-pass filter F1 and the control signal receiving circuit 41 receives the control signal through the connection point P. . The received control signal is demodulated by the control signal demodulation circuit 43 and then input to the control unit 45. On the other hand, the data generated by the control unit 45 is modulated by the control signal modulation circuit 42, transmitted as a control signal from the control signal transmission circuit 42, and sent to the transmission line L1 through the control signal path R1. The control unit 45 gives instructions for camera exposure, focus adjustment, microphone volume adjustment, etc. in the slave unit B, and receives information related to these and displays them on the monitor 22 or a display (not shown).

  Further, the door phone main unit A is provided with a plug 51 connected to a commercial power source, and a sub unit power supply unit 5 for rectifying and stabilizing the commercial power source and supplying power to the internal circuit and the sub unit B. Yes. In the demultiplexing circuit 1a, the video signal and the audio signal are superimposed on the output voltage of the slave unit power supply unit 5. The output of the demultiplexing circuit 1a is sent to the transmission line L1 through the slave unit connection terminal T1.

  By the way, the intercom main unit A has a function of displaying an image captured by the camera of the sub unit B, calling with the sub unit B, and sending / receiving a control signal to the sub unit B. However, it is desirable that these functions can be used at multiple locations indoors. Therefore, it is considered that the transmission line L2 is connected to the expansion connection terminal T2 provided in the door phone main unit A, and the expansion main unit C is provided via the transmission line L2.

  The extension master unit C can transmit video signals, audio signals, and control signals to and from the slave unit B. In other words, the doorphone base unit A has a path through which the video signal, the audio signal, and the control signal pass independently between the extension connection terminal T2 and the handset connection terminal T1.

  The signal input from the extension master C is transmitted to the demultiplexing circuit 1b and the control signal paths R2, R3, R4 provided for each connection terminal T2. The video signal separated by the demultiplexing circuit 1 b is amplified through the video signal amplification amplifier 23. This is because the frequency of the video signal is high and the amount of attenuation in the transmission lines L1 and L2 made of balanced cables is relatively large. By amplifying the video signal and transmitting it to the extension base unit C, the extension base unit A video signal relatively strong against C can be transmitted.

  The audio signal separated by the demultiplexing circuit 1b is transmitted to the handset connection terminal T1 side through the switching circuit 36. Here, the switching circuit 36 connects the communication path with only one extension connection terminal T2 to which the extension master C serving as a call destination is connected, and switches the connection according to the call destination. In general, since an audio signal close to the source signal is not subjected to a transmission frequency shift, the transmission frequency band is low, so that the amount of attenuation in the transmission lines L1 and L2 is small, and between the demultiplexing circuits 1a and 1b. A bidirectional path is formed with a simple configuration by simply connecting.

  The control signal input from the extension master unit C is transmitted between the slave unit B and the extension master unit C through the control signal paths R2 to R4 in the doorphone master unit A. That is, the signal input from the extension master C is cut through the audio signal and the video signal by the bandpass filters F2 to F4 on the extension connection terminal T2 side inserted in the control signal paths R2 to R3, and only the control signal passes. The passed control signal passes through the band pass filter F1 on the handset connection terminal T1 side, and is transmitted from the handset connection terminal T1 to the handset B through the transmission line L1. In addition, the signal input from the slave unit B is transmitted to the extension master unit C along a path in the opposite direction.

  The extension base unit C includes a plug connected to a commercial power source and a power feeding unit that rectifies and stabilizes the commercial power source. This power feeding unit is used for feeding power to the internal circuit of the expansion base unit C. Yes, power is not supplied to the slave unit B unlike the door phone master unit A. In addition, since the band pass filters F1 to F4 are interposed between the slave unit B and the extension master unit C, the power supplied from the doorphone master unit A to the slave unit B is supplied to the extension master unit C. It is never done.

  Also, the doorphone master unit A and the extension master unit C are provided with operation buttons 46 (the operation buttons of the extension master unit C are not shown). Used for. A termination resistor D is connected to the end of the transmission line L2 in order to prevent reflection of the video signal. With the above-described configuration, the doorphone master unit A and the extension master unit C can display the video from the slave unit B on the monitor 22 and can make a call with the slave unit B. Therefore, the extension base unit C is arranged at a location different from the intercom base unit A, and monitoring of images captured by the handset B and calls with the handset B can be performed at a plurality of locations.

  Therefore, in the doorphone master unit A of this embodiment, the band pass filters F1 to F4 are provided in all the control signal paths R1 to R4 that connect the connection point P to the slave unit connection terminal T1 and the extension connection terminal T2. Therefore, the audio signal, the video signal, and the DC power supply component of both the signal transmitted from the handset connection terminal T1 side and the signal transmitted from the extension connection terminal T2 side are cut and connected by the bandpass filters F1 to F4. Transmission up to point P is prevented. Therefore, since the control signal transmission circuit 42 and the control signal reception circuit 41 connected to the connection point P do not become a connection load, between the slave unit B and the doorphone master unit A, and between the slave unit B and the extension master unit C In both transmissions, attenuation of video and audio signals can be prevented.

  Needless to say, the effects of preventing ghosts and preventing crosstalk described in Japanese Patent No. 3726372, which is the background art, are all maintained in the present invention.

The block diagram which shows the door phone main | base station which is one Embodiment of this invention. Schematic diagram showing the transmission band of each signal in the doorphone master unit The block diagram which shows the door phone main | base station which is a prior art example.

Explanation of symbols

A Door phone master unit B Slave unit C Extension master unit L1 Transmission line L2 Transmission line R1 to R4 Control signal path F1 to F4 Band pass filter P Connection point T1 Slave unit connection terminal T2 Extension connection terminal 41 Control signal reception circuit 42 Control signal transmission Circuit 45 Control unit 5 Slave unit power supply unit

Claims (2)

A doorphone master unit that transmits a transmission signal including a control signal in a specific frequency band and audio signals and video signals in a frequency band different from the frequency band between the slave unit and the extension master unit via a transmission line. And
One slave unit connection terminal connected to the slave unit via the transmission line, multiple extension connection terminals connected to the extension master unit via another transmission line, and control signals from the extension master unit and slave unit Recognizes, analyzes, or newly generates a control signal, a control signal transmission circuit that transmits a control signal from the control unit, and a control signal transmitted from the extension master unit and the slave unit A control signal receiving circuit, a power supply circuit that supplies power to the slave unit via the transmission line, and a power source from the slave unit power supply unit to the extension master unit by passing only the frequency band of the control signal provided in the master unit body In the door phone master unit comprising a bandpass filter that forms a control signal path that blocks the supply and transmits the control signal separately from the audio signal and the video signal between the slave unit connection terminal and the extension connection terminal,
The control signal transmitting circuit and the control signal receiving circuit are connected to a connection point on the control signal path, and the connection point is inserted on a path between the band pass filters and only the control signal passes through. A band-pass filter is provided between a connection point and a slave unit connection terminal on a control signal path, and between a connection point and an extension connection terminal, respectively.   The control signal path is connected from the slave unit connection terminal to the connection point, branched from the connection point into a plurality of paths, and connected to each additional connection terminal one by one. The bandpass filter consists of the connection point and the slave unit. 2. The door phone main unit according to claim 1, wherein one is provided on each control signal path connecting between the connection terminals and between the connection point and the plurality of additional connection terminals.

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