JPH0134415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal transmission device,
For example, when remotely controlling a portable video tape recorder (VTR) from an external accessory device such as a television camera, the control signal is transmitted regardless of the type of external accessory device such as the television camera. The purpose is to ensure reliable transmission and remote control.

Conventionally, for example, to remotely control a VTR from an external accessory, the key matrix control lines on the VTR's main body are connected between the VTR and the external accessory, which requires a large number of connection lines. The drawback is that there are too many. Recently, methods have been used to reduce the number of connection wires by changing the voltage value depending on the VTR's operating mode, but this method has the drawbacks of poor resolution and the need for encoder/decoder circuits. . Also, if you want to remotely control a VTR from an external device such as a TV camera, where the number of connection lines is fixed and the signals sent by each connection line are fixed, use the control lines of the key matrix described above. This method is impossible due to the limited number of connection wires, and the method of changing the voltage value depending on the operation mode degrades the resolution as the connection wires get longer, making it difficult to transmit a lot of information. It is.

Furthermore, the conventional device will be specifically explained using FIG. FIG. 1 shows a schematic configuration of a portable VTR and external accessories connected to it. The attached devices connected to the portable VTR 1 include a wired remote control 2, a tuner device 3, a television camera 5, and the like. In Figure 1, these are:
Connecting wires 6, 7, 8 and connectors 9, 1, respectively
It is connected to VTR1 through 0 and 11.
The wired remote control 2 is used to operate the VTR 1 at a location away from the VTR 1. The tuner device 3 receives on-air broadcast waves with an antenna 12, extracts video and audio signals of arbitrary channels from the broadcast waves, and sends the signals to the VTR 1. The tuner device 3 also has a built-in timer function, so that programs on any channel can be recorded at any time. The signal sent from the tuner device 3 to the VTR 1 through the connection line 7 and connector 10 is as follows.
In addition to video and audio signals, control signals for operating the VTR 1, such as when setting a timer or during timer recording, must also be sent. Further, the tuner device 3 can select a channel using a wireless remote controller 4 such as an infrared remote controller, and can also operate the VTR 1 using the wireless remote controller 4. In this way, from tuner device 3,
A control signal to control the VTR1 is sent out. TV camera 5 is TV camera 5
The video and audio signals captured by the camera are sent to VTR1. Furthermore, when the VTR 1 is in a playback state, the playback image can be viewed on a viewfinder comprised of an ultra-compact cathode ray tube or the like within the television camera 5. When shooting with the TV camera 5, the user holds the TV camera 5 and faces the subject, and when using the extension cable,
Shooting will be done at a location quite far away from VTR1.
At this time, you can operate the VTR 1 from the TV camera 5, play back the recorded part, check it with the viewfinder, and continue shooting again from the TV camera 5.
A control signal that can control the VTR1 is sent out.

However, the tuner device 3, television camera 5, etc. have various types that are not compatible with each other. Therefore, it would be very convenient if it were possible to make the conventional tuner device/TV camera compatible with the VTR. However, in this case, since the connection wire between the conventional VTR and the TV camera/tuner device is used as is, it is not possible to add a new signal wire to control the VTR, and the existing signal wire is shared. to the signal line
It is necessary to carry the VTR control signal,
The disadvantages are that the configuration is extremely complex and it is difficult to transmit a large amount of information.

The present invention overcomes these drawbacks, e.g.
To provide a signal transmission device that efficiently exchanges information between a VTR and an external accessory device using a conventionally used connection line and is compatible with the connection with the conventional external accessory device. It is something.

Conventionally, for example, the number of connection lines between a VTR and a television camera has been approximately determined by the VTR system, and has been around 10. And in most VTRs,
The pin number of the connector and the signal flowing through it have been determined, ensuring compatibility with conventional television cameras. Signals flowing through the connection line between the VTR and the television camera include video signals, audio signals, ground, tape start/stop signals from the television camera to the VTR, and signals indicating the recordable state from the VTR to the television camera. In the present invention, for example, a line through which a signal varying in binary levels of High Level and Low Level flows from the VTR to the television camera, and another line, are used.
Information is exchanged between the television camera and the VTR, and when a conventional television camera is connected, the function of the television camera is not impaired in the slightest.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a circuit diagram of a signal transmission device that is an embodiment of the present invention. In FIG. 2, the VTR 20, television camera 30, wired remote control 40, and tuner 50 are connected to connectors 31, 41, and 50, respectively.
51. Information is exchanged between each device using two connection lines.
Inside the VTR 20, there are a mechanism control circuit 21, a serial data signal input/output circuit 22 (hereinafter abbreviated as SD I/O circuit), an inverter circuit 29,
There are serial clock generators 26,27. Inside the television camera 30 and wired remote control 40, there are SD I/O circuits 32, 42 and inverter circuits 39, 49. Although the specific configuration of the tuner 30 has been omitted, it similarly includes an SD I/O circuit and an inverter circuit. SD I/O circuit 22, 42
A serial clock is supplied from the serial clock generator 26 to the SCK terminal of the SD I/O circuit of the tuner 50. SD in TV camera 30
Only I/O circuit 32 is supplied with signals from serial clock generator 27. The connection line 61 between the serial clock generator 27 and the SD I/O circuit 32 uses a line through which signals flow from the VTR to the camera, among the conventional connection lines between the VTR and the television camera. The signal flowing from the VTR to the camera is received by the serial clock generator 27 from the mechanism control circuit 21, superimposed on the serial clock, transmitted, and received by the control circuit 36 in the camera 30. Furthermore, SD I/O circuit 2
2,42 SI terminals are connected by one signal line 60,
SO terminal is resistor 23, 43 and transistor 24,
The signal line 60 is connected to the signal line 60 via inverter circuits 29 and 49 composed of 44. Chuyuna 5
0 also has the same configuration as the wired remote controller 40. The SO terminal of the SD I/O circuit 32 of the camera 30 is connected to a signal line 62 connected to the SI terminal via an inverter circuit 39 consisting of a resistor 33 and a transistor 34.
1 and is connected to a signal line 60 via a gate circuit 28 within the VTR 20. FIG. 3 shows signal waveforms at each part in such a configuration. The signals shown in FIGS. 3a and 3b are the output signals of serial clock generators 26 and 27, respectively. In FIG. 3, the explanation will be made using 4-bit serial clock signal blocks m ₁ , m ₂ , m ₃ , and m ₄ with a period t ₀ , but the serial clock signal block may have any number of bits. It doesn't matter how many blocks there are. The difference between signal a and signal b is that a signal other than the serial clock is sent during any non-clock period. In this embodiment, the serial clock generator 27 outputs the signal received from the mechanism control circuit 21 at a non-clock interval _t4 . As mentioned above, each SD I/O circuit
This serial clock signal is input to the SCK terminal, and a signal is output from the SO terminal in accordance with the serial clock signal, and is connected to serial data lines 60 and 62 via respective inverter circuits. By the way, this serial data line 60, 6
2, if the gate circuit 28 is closed, it will become a single line, and if the signals are output from the SO terminals of each SD I/O circuit at the same time, the signals will be mixed on the serial data line, so the main line In the preferred embodiment, each serial signal block is allocated to a respective SD I/O circuit. That is, for example, block m ₁ has camera 30
block _m2 is for the SD I/O circuit 42 in the wired remote control 40,
Block _m3 is set for the SD I/O circuit in the tuner 50, block _m4 is for the SD I/O circuit 22 in the VTR 20, and each SD I/O circuit is set as the allocated block. Outputs any signal from the SO terminal, otherwise it is Low
Transistors 24, 34, 4 are connected to the SO terminal via a resistor by outputting a Level signal.
4 is cut off. As a result, on the serial data line, during each block period, only the signal output from the SO terminal of the SD I/O circuit allocated to it is valid. Note that the signal on the serial data line and the signal output from the SO terminal have a complementary relationship. Figure 3 c, d and f are SD I/O circuits 32 and 4, respectively.
FIG. 3e shows the output waveform of the SO terminal of the SD I/O circuit in the tuner 50. When the button 37 for operating the VTR 20 is pressed, the control circuit 36 in the camera 30 sets a corresponding code in the SD I/O circuit 32 and outputs it from the SO terminal during the period of block _m1 . When the operation button 47 of the VTR 20 is pressed, the control circuit 46 in the wired remote control 40 sets a corresponding code in the SD I/O circuit 42 and outputs it from the SO terminal during a period of block _m2 . When the tuner 50 receives the operation code for the VTR 20 from the wireless remote controller 52, it outputs the corresponding code from the block _m3 . Block _m4 is used to notify external equipment of the status and information of the VTR 20. In this way, the signal waveform of the serial data line 60 becomes as shown in FIG. 3g, and information can be exchanged between each device and other devices.

Now, in this embodiment, in the above configuration, the serial clock line 6 between the camera 30 and the VTR 20 is
1 is characterized by the use of a conventional line for signals to flow from the VTR to the camera. Connector 3
When the camera 30 is not connected to block m1, the pull-up resistor 25 causes all serial data during the block _m1 to become a high level signal.
Mechanism control circuit 21 is block _m1
When all the serial data in the period continues to be at High Level, the SD I/
It determines that the O circuit 32 is not connected, and outputs a signal to the serial clock generator 27 to stop outputting the serial clock. When the serial clock generator 27 receives this signal, it stops sending the serial clock and enters a non-clock period.
Make the signal sent in _t4 always output.
The output waveform of the serial clock generator 27 at this time is shown in FIG. 3B. For this reason, naturally the connector 31
During normal operation with the SD I/O circuit 32 connected to the SD I/O circuit 32, the serial data lines 62 all go to High _Level ( 1111), which is not related to VTR operation, and the serial clock signal continues to be transmitted from the serial clock generator 27. Further, the mechanism control circuit 21 is
When the period of block _m1 changes from all High Level states to all Low Level states, the serial clock generator 27 is commanded to output the serial clock, and the output waveform of the serial clock generator 27 is as follows. It will look like Figure 3B again. For this reason, the camera 30 with a built-in SD I/O circuit 32
However, when it is connected to the connector 31, since the serial clock is not being output from the serial clock generator 27 at this time, first, the serial data line 62 is unconditionally set to Low Level for a certain period of time.
Waits for serial clock to be sent. When the serial clock arrives, it enters normal operation, and if it does not come, it is determined that the VTR 20 is connected without a built-in SD I/O circuit 22, receives only the signal on the connection line 61, and resumes the conventional system operation. Do this.

Next, a case will be described in which a conventional television camera is connected to the connector 31 of the VTR 20.
When connected to VTR20, serial data line 62
When a television camera is connected, the signal becomes High Level, all High Level signals are input to the mechanism control circuit 21 during block _m1 , so as mentioned above, the serial clock generator 27 Since the serial clock is not output and only the signal sent through the conventional connection line 62 is output, the television camera 30 operates in the same way as when connected to a conventional VTR. Next, a case will be described in which the television camera 30 whose serial data line 62 becomes low level is connected. In this case, if the gate circuit 28 is always closed, the serial data line 60 will also be at a low level during all periods, making it impossible to send data in blocks m ₂ , m ₃ , and m ₄ . Therefore, opening and closing of the gate circuit 28 must be controlled by the mechanism control circuit 21. By the way, as mentioned above, even when the TV camera 30 with the built-in SD I/O circuit 32 is connected to the connector 31, the serial data line 62 is set to Low as a serial clock request signal.
This distinction must be made in order to make the level. For this distinction, if a TV camera 30 with a built-in SD I/O circuit is connected, the VTR 20
When the serial clock generator 27 of the camera 30 sends a signal with the waveform shown in FIG. When connecting a TV camera, where the data line becomes low level, take advantage of the fact that the no-clock period remains low level no matter how long it lasts. In other words, the mechanism control circuit 21 ensures that all serial data during the period of block _m1 is High.
When the clock is no longer at Level (1111), command the serial clock generator 27 to output the serial clock, and after a certain period of time, input the signal on the serial data line 60 during an arbitrary clockless period, and then If it is at Level, it instructs the serial clock generator 27 to continue outputting the serial clock, and if it is at Low Level, it instructs the serial clock generator 27 to stop the serial clock. Alternatively, if the serial data line 62 of the camera 30 is set not to be a low level signal during normal operation, the mechanism control circuit 21 can change the serial data during the period of block _m1 from all high level to all low level.
When the clock changes to , the serial clock generator 27 is commanded to output the serial clock, and even after a certain period of time, if all the serial data during the period of block _m1 is at low level, the serial clock is stopped. In this case, the mechanism control circuit 21 does not need to read the serial data during the non-clock period.

As described above, according to the present invention, for example, the connection line between an existing portable VTR and its external accessory equipment can be used, and the connection with the existing equipment can also be made compatible. It is possible to efficiently and reliably transmit remote control signals to operate the VTR from the VTR and data signals from the VTR to external accessories. Also, currently
There are also microcomputers with built-in SD I/O circuits, which can be used to replace the control circuits and SD I/O circuits of each external accessory device with a single microcomputer. Also, VTR
It is also possible to perform the mechanism control circuit, two serial clock generators, and the SD I/O circuit with one microcomputer, and the number of parts can be greatly reduced.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a portable VTR system, FIG. 2 is a block diagram of a signal transmission device which is an embodiment of the present invention, and FIG. 3 is a signal waveform diagram of each part of the device. 1...VTR, 2...Wired remote control, 3
...Tuner device, 4...Wireless remote control,
5... Television camera, 22, 32, 42... Serial data signal input/output circuit, 21... Mechanism control circuit, 28... Gate circuit, 26,
27... Serial clock generator, 36, 46...
...control circuit, 29, 39, 49...inverter circuit.

Claims (1)

[Claims] 1. N-bit serial clock signal blocks m ₁ , m _{2 .} . . m _k (k is any integer) with a period t ₀ and non-clock intervals t ₁ , t ₂ . . . between the blocks. a first serial clock generator that generates a group of time-series pulses with a period T ₀ and a period _T 0 of t _k ; a second serial clock generator that generates a time-series pulse group on which different state determination signals are superimposed; and a second serial clock generator that outputs data corresponding to each serial clock signal block based on the serial clock signal block. a plurality of data generators, the second serial clock generator supplies a signal only to a specific data generator among the data generators, and other data generators other than the specific data generator is supplied with a signal from the first serial clock generator, the data output from each data generator is transmitted through one data line, and the data line of the specific data generator is a data line. A signal transmission device, characterized in that the signal transmission device is connected to the one data line via a gate circuit controlled by the state of the above signal. 2. Depending on the content of specific data determined in advance,
A determination circuit that determines the presence or absence of a specific data generator and outputs a command to cause the second serial clock generator to generate only a state determination signal different from the serial clock signal if the specific data generator is not present. Claim 1 characterized in that it has
Signal transmission device as described in section.