JP2001268549A - A single cable transmission device for supplying signal and power of monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single cable transmission device capable of transmitting both of a signal and power for a monitoring system through a single cable, attaining long distance transmission by transmitting the signal by a carrier system, attaining bidirectional transmission by transmitting the signal by a frequency division system and to provide also a power voltage/output load state display device capable of directly detecting the trouble of the system and quickly removing the cause of the trouble. SOLUTION: A remote device 10 included in the system is provided with a 1st modulator 12 for converting a 1st set base band signal inputted from the external into a 1st modulation carrier signal and a 1st filter module 13 for receiving the 1st modulation carrier signal and power inputted from a single cable 14, separating the 1st modulation carrier signal and the power by using respectively different frequency bands, respectively ?outputting the separated 1st modulation carrier signal and supplied power, and applying the outputted 1st modulation carrier signal to the cable 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a signal transmission device using a cable. In particular, it relates to a single cable transmission for signal and power transmission for a monitoring system.

[0002]

2. Description of the Related Art In a current surveillance system, for example, a unidirectional surveillance system, a baseband signal such as a video signal, an audio signal and a control signal is transmitted, and a camera on a front side (remote) is transmitted. The power supply between the front and local (local) monitors is typically provided via a number of cables (e.g., coaxial cables). However, such transmission techniques have a number of drawbacks: (1) the need for multiple cables makes installation of the system difficult and results in increased system costs; (2) long distance baseband. (3) When switching to a two-way monitoring system, the disadvantages of (1) and (2) are compounded; (4) From the near side (local) When there is a problem with the power supply to the other side (remote), it is difficult to directly know the operation state of the power supply function or the load element (for example, a camera). In any case, special equipment is needed to find out and fix the cause.

Accordingly, the present invention provides an improved single-cable transmission for the transmission of signals and power for a monitoring system. This device overcomes the disadvantages of the prior art monitoring system described above.

One object of the present invention is that only one cable is required for the transmission of various signals and power, thus simplifying the installation of the system, reducing the cost of the system, and making it easy to use even for amateurs. And a transmission device.

Another object of the present invention is to provide a transmission device that transmits a signal by a carrier method or a carrier wave method and enables long-distance transmission.

It is still another object of the present invention to provide a transmission device which transmits a signal in a frequency division system and makes it possible to perform an operation trial by transmitting the signal in a two-way manner, and which is easy for a user to use.

A further object of the present invention is to provide a power voltage / output load status display device, which allows a user to directly find the cause of a malfunction, promptly remove the cause, shorten repair time, and reduce the time required for repair. This is to provide a transmission device that can be used even by other users.

[0008]

SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided an innovative single-cable transmission system for signaling and powering a monitoring system, including a remote unit. Is done. The remote device receives a first modulator for converting a first set of baseband signals input from the outside into a first modulated carrier signal, receives the first modulated carrier signal, and power input from a single cable. A first filter module that separates the first modulated carrier signal and the power using different frequency bands, and outputs the separated first modulated carrier signal and the power, respectively. The modulation carrier signal is applied to a single cable.

In accordance with another aspect of the present invention, an innovative single-cable transmission for monitoring system signaling and power supply includes a local device. This local device receives a first modulated carrier signal input from a single cable, receives power input from the outside, and separates the first modulated carrier signal and power by using different frequency bands. And a second modulation filter module for outputting the separated first modulated carrier signal and power, respectively, and applies the output power to a single cable. And a first demodulator for converting the first modulated carrier signal output from the second filter module into a first set of baseband signals.

In yet another aspect of the present invention, a first filter module of the remote unit of the innovative single cable transmission system for signaling and power supply of the monitoring system comprises:
A second modulated carrier signal received from a single cable is received, and the second modulated carrier signal and the first modulated carrier signal are separated using different frequency bands.
Output the modulated carrier signal. The remote device further comprises a first
A second set of baseband signals for converting the second modulated carrier signal output from the filter module to a second set of baseband signals;
Includes demodulator.

In accordance with yet another aspect of the present invention, a local unit of an innovative single-cable transmission system for signaling and powering a surveillance system includes a second set of externally input baseband signals. Receiving a second modulator for converting to a second modulation carrier signal, a first modulation carrier signal input from a single cable, a second modulation carrier signal from the second modulator, and power input from the outside, Separating the first modulated carrier signal, the second modulated carrier signal, and the power using different frequency bands;
It includes a separated first modulated carrier signal, a second modulated carrier signal, and a second filter module for outputting power, respectively. The output second modulated carrier signal and power are applied to a single cable. And a first demodulator for receiving the first modulated carrier signal output from the second filter module and converting the first modulated carrier signal into a first set of baseband signals.

In accordance with another aspect of the present invention, a remote single cable transmission remote for monitoring system signaling and powering is provided for detecting power voltage and status of external device load elements. The power voltage connected between the power output from the first filter module and the external device /
An output load status display device is included.

In accordance with yet another aspect of the present invention, an innovative single-cable transmission for monitoring system signaling and powering is powered at a remote device rather than a local device.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS In order to explain the features and advantages of the present invention in more detail, a detailed description will be given of an embodiment of the present invention with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a first preferred embodiment of a single cable transmission device for supplying signals and power of a monitoring system according to the present invention. This device includes a front device or remote device 10 and a near device or local device 11. The remote device 10 is the modulator 1
2 and a filter module 13. The modulator 12 receives a baseband signal input from an external device, for example, a video signal and an audio signal from a camera (not shown), and a set of control signals from a control device such as a switch (not shown). Convert the baseband signal to a modulated carrier signal. This modulation is performed by, for example, a coherent AM method. Alternatively, it is performed in a non-coherent manner and the modulator 12 is further provided with a summing circuit to integrate or integrate the modulated carrier signal.

The filter module 13 receives the modulated carrier signal output from the modulator 12 and the power from the single cable 14, separates the modulated carrier signal and the power using different frequency bands, and separates the modulated carrier signal from the power. The carrier signal and the power are output, respectively, and the output modulated carrier signal is applied to the single cable 14, and the output power is applied to the modulator 12 and an external device such as a camera via the cord 15.

The local device 11 includes a filter module 16 and a demodulator 17. The filter module 16 receives the modulated carrier signal input from the single cable 14 and the power input from the outside via the code 18, separates the modulated carrier signal and the power using different frequency bands, and separates the power. The modulated carrier signal and the output power are output, and the output power is applied to the single cable 14.

The demodulator 17 receives the modulated carrier signal output from the filter module 16 and converts the modulated carrier signal into a set of baseband signals such as a video signal, an audio signal, and a control signal. If the modulator 12 is performed in a coherent AM scheme, demodulation is performed in an AM detection scheme. If the modulator 12 is implemented in a non-coherent manner, the demodulation will be in a phase locked loop (PL
L). External power can be applied to the demodulator 17.

The external power source may be a DC or AC power supply. The voltage range of the power supply changes according to the length of the single cable 14. RG-59 / 100m to 200m
In the case of a U coaxial cable, it has been confirmed that a DC power supply of 6V to 24V can be used. Alternatively, an AC power supply having a similar voltage and a frequency of 800 Hz or less can be used. To use an AC power supply, the power output from the filter module 13 via the cord 15 is rectified and applied to the modulator 12 and an external device, respectively.

FIG. 2 shows the filter module 1 of FIG.
Block diagrams of the preferred embodiments 3 and 16 are shown.
The filter module 13 is a band pass filter 21
And a low-pass filter 22. The filter module 16 includes a band pass filter 23 and a low pass filter 24. The band pass filter 21 and the low pass filter 22 have different frequency band characteristics, and the band pass filter 23 and the low pass filter 24 also have different frequency band characteristics. The band-pass filters 21 and 23 have the same frequency band characteristics, and the low-pass filters 22 and 24 also have the same frequency band characteristics. For example, the band-pass filters 21 and 23 can have a frequency band 31 as shown in the frequency spectrum diagram of FIG. Within the modulated carrier signal, frequency bands 33, 34 and 35 can be considered for video, audio and control signals, respectively.
The low-pass filter 22 and the low-pass filter 24 are D
It can have a frequency band 32 in a C power supply or an AC power supply. In this arrangement, the filter module 13 uses the bandpass filter 21 and the lowpass filter 22 to use the different frequency bands to modulate the modulated carrier signal from the modulator 12 and the single cable 1.
4 and output the separated modulated carrier signal and power, respectively. With the band-pass filter 23 and the low-pass filter 24, the filter module 16 uses different frequency bands to separate the modulated carrier signal from the single cable 14 from external power, and separates the separated modulated carrier signal and power. Output each.

FIG. 4 is a block diagram showing a second embodiment of a single cable transmission device for supplying signals and power of the monitoring system according to the present invention. This embodiment is based on a single-cable transmission for the supply of signals and power as shown in FIG. The device is capable of transmitting bidirectional signals with power. The device of the second preferred embodiment includes a remote device 40 and a local device 41. Remote device 40
A modulator 42 and a filter modulator 43;
The single cable 44, the filter module 47 and the demodulator 48 of the local device 41 are connected to the modulator 12, the filter module 13, the single cable 14, the filter module 16 and the demodulator 1 shown in FIG.
7, which converts a baseband signal set inputted from the outside into a modulated carrier signal, separates the modulated carrier signal and power using different frequency bands, transmits the separated modulated carrier signal, and transmits The modulated carrier signal is converted to a set of baseband signals. The difference is that the local device 41 is
9 which converts another set of baseband signals into modulated carrier signals, is separated using a different frequency band by a filter module 47, transmitted by a single cable 44, and uses a different frequency band by a filter module 43. And a demodulator 45 added to the remote device 40 converts the signal into another set of baseband signals. Local device 4
The external input power received at 1 is applied to the filter module 4
7 using different frequency bands, transmitted by a single cable 44, and
And is applied to the modulator 42, demodulator 45 and external devices.

FIG. 5 shows filter modules 43 and 47.
A block diagram of the preferred embodiment of FIG. The filter module 43 converts the band pass filter 51 and the low pass filter 52 into the band pass filter 2 of FIG.
1 and the low-pass filter 22. The filter module 47 includes a band pass filter 54 and a low pass filter 55 as the band pass filter 23 and the low pass filter 24 in FIG. The filter module 43 further includes a bandpass filter 5
3, and the filter module 47 further includes a bandpass filter 56. The band-pass filter 51, the band-pass filter 53, and the low-pass filter 52 have different frequency band characteristics,
Band pass filter 54, band pass filter 56
The low-pass filter 55 also has different frequency band characteristics. The band-pass filters 51 and 54 have the same frequency band characteristics, the band-pass filters 53 and 56 have the same frequency band characteristics, and the low-pass filters 52 and 55 also have the same frequency band characteristics. They have the same frequency band characteristics. For example, the band-pass filters 51 and 54 can have a frequency band 61 as shown in the frequency spectrum diagram of FIG. These frequency bands 64, 65 and 66 can be considered as video, audio and control signals, respectively, in the modulated carrier signal. Further, the band-pass filter 53 and the band-pass filter 56 can have a frequency band 62 shown in the frequency spectrum diagram of FIG. Frequency bands 67, 68 and 69
Can be considered as a video signal, an audio signal, and a control signal, respectively, in the modulated carrier signal. The low-pass filter 52 and the low-pass filter 55 are D
It can have a frequency band 63 for C power supply or AC power supply. Therefore, the filter module 43
And 47 can separate the two modulated carrier signals and the power using different frequency bands, and can output the separated modulated carrier signals and the power, respectively.

FIG. 7 is a block diagram of a third preferred embodiment of the present invention. Remote device 71 functions similarly to remote device 10 of FIG.
3 is included. The modulated carrier signal and the electric power are transmitted through the single cable 74, and the electric power output from the filter module 73 is supplied through the cord 75. The remote device 71 further includes a power voltage / output load status display device 76 connected between the power element output from the filter module 73 via the cord 75 and the external device. Detect the status of an element.

FIG. 8 is a block diagram of a preferred embodiment of the power voltage / output load status display device 76 of FIG. This device comprises a power voltage status detector 81 and a load status detector 82
And a display module 83. The power voltage status detector 81 detects the voltage status of the power output from the filter module 73 via the cord 75 and outputs a signal indicating the power voltage status to the line A. The load status detector 82 detects the load status of the external device connected to the power element output from the filter module 73 via the cord 75, and outputs a signal indicating the load status to the line B.
The display module 83 provides an appropriate operation for the signal indicating the status of the power voltage from the line A and an appropriate operation for the signal indicating the status of the load from the line B, and displays the status of the power voltage and the load. I do.

FIG. 9 shows a preferred embodiment of the electric circuit included in the block diagram of FIG. As shown in FIG. 9, the power voltage status detector 81 has its positive (+) input pin connected to a reference voltage 92.
Connected to the positive electrode of the
And an operation amplifier 91 connected to the power element output from the filter module 73. The negative electrode of the reference voltage 92 is grounded. The reference voltage 92 is designed to have a voltage value close to the power voltage that normally operates the external device. Therefore, the operation amplifier 91 can detect the status of the power voltage output from the filter module 73 via the cord 75 and output a signal indicating the status of the power voltage to the line A. The load state detector 82 has an operation amplifier 93 having its negative (-) input pin connected to the negative electrode of the reference voltage 94.
Contains. The positive electrode of reference voltage 94 is coupled to the power element from cord 75 and one end of resistor 95. The other end of the resistor 95 is coupled to the positive (+) input pin of the operational amplifier 93, and the code 75
Output power to an external device. The operating current of the load element of the external device passes through the resistor 95. The reference voltage 94 is designed to have a voltage value close to the voltage of the resistor 95 provided by this operating current. As a result, the operation amplifier 93 detects the load status of the external device connected to the power element output from the filter module 73 via the cord 75, and outputs a signal indicating the load status to the line B. The display module 83 includes the inverter 9
6, including a NAND gate 97, an OR gate 98, an LED display 99, and current limit resistors 97G and 98R. LED display 99 is green LED 99G and red L
ED99R. The inverter 96, the NAND gate 97, and the OR gate 98 collectively function as a signal detector, and further, a signal for decoding a signal from the line A indicating a power voltage state and a signal from the line B indicating a load state. Functions as a decoder. The decoded signal indicating the state of the power voltage and the state of the load is indicated by a line G.
And R, output through the current limit resistors 97G and 97R, respectively, the green LED 99G and the red LED
The status is displayed with 99R.

Next, the operation principle of the status display device 76 shown in FIG. 9 will be described with reference to a table shown in FIG.

1. When the power supply is sufficient and there is no load element, the operation amplifier 91 outputs a low (L) voltage to the line A, the operation amplifier 93 also outputs a low (L) voltage to the line B, and the line G is output. High (H)
Voltage, the line R is set to a low (L) voltage, and the green L
Only the ED 99G is turned on, and the LED display 99 turns green. 2. When the power supply is sufficient and the load element is present,
The operation amplifier 91 outputs a low (L) voltage to the line A, the operation amplifier 93 outputs a high (H) voltage to the line B, and sets the line G to a low (L) voltage.
When the line R is set to a high (H) voltage, only the red LED 99R is turned on, and the LED display 99 becomes red. 3. When the power supply is insufficient and no load element is present, the operational amplifier 91 outputs a high (H) voltage on line A, the operational amplifier 93 outputs a low (L) voltage on line B, and To a high (H) voltage,
When the line R is set to a high (H) voltage, the green LED 99G
And the red LED 99R are both turned on, and LE
The D display 99 is yellow. 4. When the power supply is insufficient and a load element is present, or when the load element is in an insufficient power supply state, the operation amplifier 91 outputs a high (H) signal to the line A.
A voltage is output, the operation amplifier 93 also outputs a high (H) voltage to the line B, the line G is set to the high (H) voltage, the line R is set to the high (H) voltage, and the green LED 9 is output.
9G and the red LED 99R are both turned on,
The LED display 99 becomes yellow.

Further, based on the same principle, the embodiment of the single cable transmission device for transmitting signals and power of the monitoring system of the present invention can apply the power of the remote device to the local device.

[0029] Current transmission devices for cable TV systems and outdoor down-converter transmission devices for satellite TV receivers also employ the carrier signal transmission method and provide power to the transmission line. However, cable TV systems transmit signals in broadcast form, which requires a myriad of terminal user equipment and supplies power only for the signal amplifiers on the transmission lines and not for the terminal user equipment. is there.
The outdoor down-converter transmission device of the satellite TV receiver mainly performs frequency conversion, and the electric power is used for the outdoor down-converter. The two types of transmission devices described above are different from the transmission device of the present invention.

Although the present invention has been described in detail based on the above-described embodiments, those skilled in the art can also make changes and improvements. For example, with a suitable signal decoder and LCD display, the display module 83 can display power voltage status and load status in Chinese, English, or numbers, symbols, and the like. Such improvements and modifications are intended to be included in the appended claims.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first preferred embodiment of a single cable transmission device for supplying signals and power of a monitoring system according to the present invention.

FIG. 2 is a block diagram of a preferred embodiment of the filter module of FIG.

FIG. 3 is a frequency spectrum diagram for the filter module of FIG. 2;

FIG. 4 is a block diagram of a second preferred embodiment of a single cable transmission device for supplying signals and power of a monitoring system according to the present invention.

FIG. 5 is a block diagram of a preferred embodiment of the filter module of FIG.

FIG. 6 is a frequency spectrum diagram for the filter module of FIG.

FIG. 7 is a block diagram of a third preferred embodiment of a single cable transmission device for supplying signals and power of a monitoring system according to the present invention.

FIG. 8 is a block diagram of a preferred embodiment of the power voltage / output load status display device of FIG. 7;

FIG. 9 is a circuit diagram of a preferred embodiment utilized in the apparatus of FIG.

FIG. 10 is a circuit diagram of a preferred embodiment utilized in the apparatus of FIG.

[Explanation of symbols]

10, 40, 71 ... remote device 11, 41 ... local device 12, 42, 49, 72 ... modulator 13, 16, 43, 47, 73 ... filter module 14, 44, 74 ... single cable 15, 75 ... code 17, 45, 48 ... demodulators 21, 23, 51, 53, 54, 56 ... band-pass filters 22, 24, 52, 55 ... low-pass filters 31, 33, 34, 35, 61, 62, 63, 64, 6
5, 66, 67, 68, 69 frequency band 76 power voltage / output load status display device 81 power voltage status detector 82 load status detector 83 display module

Claims (52)

[Claims] 1. A single cable transmission device for transmitting signals and power of a monitoring system, comprising a remote device, the remote device transmitting a first set of baseband signals externally input to a first device. A first modulator that converts the signal into one modulated carrier signal, receives the first modulated carrier signal, and power input from a single cable, and converts the first modulated carrier signal and the power using different frequency bands. A first filter module that separates and outputs the separated first modulated carrier signal and the power, and applies the output first modulated carrier signal to the single cable. A single cable transmission device. 2. A local device further comprising: a local device for receiving a first modulated carrier signal input from a single cable and an externally input power, and receiving the first modulated carrier signal and the power. A second filter module for separating power from power using a different frequency band and applying the separated power to the power; receiving the first modulated carrier signal output from the second filter module; And a first demodulator for converting the signal to a first set of baseband signals. 3. The first filter module of the remote device further receives a second modulated carrier signal input from a single cable, and converts the second modulated carrier signal, the first modulated carrier signal, and the power into different frequency bands. Outputting the separated second modulated carrier signal, and the remote unit further receives the second modulated carrier signal output from the first filter module, and outputs the second modulated carrier signal. 2. The single cable transmission of claim 1 including a second demodulator for converting the second set of baseband signals into a second set of baseband signals. 4. A local device further comprising a second modulator for converting a second set of baseband signals input from the outside into a second modulated carrier signal, and a local input from a single cable. A first modulated carrier signal and said second modulated carrier signal from said second modulator;
Receiving power input from outside, separating the first modulated carrier signal, the second modulated carrier signal, and the power using different frequency bands, and separating the separated first modulated carrier signal and the separated power. A second filter module that outputs a second modulated carrier signal and the power respectively, and applies the output second modulated carrier signal and the power to the single cable; and the second filter module that is output from the second filter module. 4. The single cable transmission of claim 3 including: a first demodulator receiving the first modulated carrier signal and converting the first modulated carrier signal to a first set of baseband signals. . 5. The single-cable transmission device according to claim 1, wherein the power output from the first filter module is applied to the first modulator and an external device. 6. The single cable transmission device according to claim 2, wherein the first demodulator receives power input from outside. 7. The power output from the first filter module is applied to a first modulator, a second demodulator,
The single cable transmission device according to claim 3, wherein the single cable transmission device is applied to an external device. 8. The single cable transmission device according to claim 4, wherein the first demodulator and the second modulator receive electric power input from outside. 9. The single-cable transmission device according to claim 1, wherein the cable is a coaxial cable. 10. The single cable transmission device according to claim 1, wherein the baseband signal includes a video signal, an audio signal, and a control signal. 11. The single cable transmission device according to claim 1, wherein the power is DC power. 12. The single-cable transmission device according to claim 1, wherein the power is AC power. 13. The single cable transmission device according to claim 11, wherein the electric power has a voltage that changes according to the length of the single cable. 14. The single cable transmission device according to claim 12, wherein the electric power has a voltage that changes according to the length of the single cable. 15. The single-cable transmission device according to claim 12, wherein the power output from the first filter module is rectified and applied to the first modulator and an external device. 16. The device according to claim 1, wherein the first demodulator receives externally input power after rectification.
2. The single cable transmission device according to 2. 17. The single-cable transmission device according to claim 12, wherein the power output from the first filter module is rectified and applied to the first modulator, the second demodulator, and an external device. 18. The single cable transmission device according to claim 12, wherein the first demodulator and the second modulator receive externally input power after rectification. 19. Modulation is coherent AM
The single cable transmission device according to any one of claims 1 to 8, wherein the single cable transmission device is executed in a system. 20. The single-cable transmission device according to claim 19, wherein the demodulation is performed by an AM detection method. 21. A single cable according to claim 1, wherein the modulation is performed in a non-coherent manner, the modulator further provided with an adder circuit for integrating the modulated carrier signal. Transmission device. 22. The method according to claim 21, wherein the demodulation is performed in a phase locked loop (PLL).
A single cable transmission as described. 23. The single-cable transmission according to claim 1, wherein the first filter module and the second filter module include at least one band-pass filter and one low-pass filter. apparatus. 24. The apparatus further includes a power voltage / output load status display device connected between the power output from the first filter module and the external device, and detects the power voltage and the operation status of the external device load. The single-cable transmission device according to claim 5 or 7, wherein: 25. The single cable transmission device according to claim 24, wherein the power voltage / output load status display device includes a power voltage status detector, a load status detector, and a display module. 26. The power voltage condition detector and the load condition detector include at least one operational amplifier and one reference voltage, and the display module includes one decoder and an LED display device. The single-cable voltage device according to claim 25, characterized in that: 27. A single cable transmission device for the transmission of signals and power of a monitoring system, comprising a remote device, said remote device transmitting a first set of baseband signals externally input to a first device. A first modulator for converting the signal into one modulated carrier signal, receiving the first modulated carrier signal and power input from the outside, and separating the first modulated carrier signal and the power using different frequency bands And a first filter module for outputting the separated first modulated carrier signal and the power to a single cable. 28. A local device further comprising a local device for receiving a first modulated carrier signal and power input from a single cable, and converting the first modulated carrier signal and the power to different frequencies. The first band is separated using a band.
A second filter module for outputting a modulated carrier signal and the power, respectively; receiving the first modulated carrier signal output from the second filter module, and converting the first modulated carrier signal to a first signal;
28. The single cable transmission of claim 27, comprising: a first demodulator for converting to a set of baseband signals. 29. The first filter module of the remote device further receives a second modulated carrier signal input from a single cable, and separates the second modulated carrier signal, the first modulated carrier signal, and the power into different frequency bands. And outputting the separated second modulated carrier signal, the remote unit receives the second modulated carrier signal output from the first filter module, and converts the second modulated carrier signal into a second modulated carrier signal. Second to convert to two sets of baseband signals
28. The single cable transmission of claim 27, further comprising a demodulator. 30. A local device, further comprising a second modulator for converting a second set of baseband signals input from the outside into a second modulated carrier signal, and a single input from a single cable. Receiving the first modulated carrier signal and power and the second modulated carrier signal from the second modulator, utilizing the first modulated carrier signal, the second modulated carrier signal and the power in different frequency bands; And the separated first modulated carrier signal and the separated second modulated carrier signal.
A second carrier signal and the power are output, and the output second modulated carrier signal is applied to a single cable.
A filter module, receiving the first modulated carrier signal output from the second filter module, and converting the first modulated carrier signal to the first modulated carrier signal.
30. The single cable transmission of claim 29, comprising: a first demodulator for converting to a set of baseband signals. 31. The single-cable transmission device according to claim 27, wherein the first modulator receives externally input power. 32. The single cable transmission device according to claim 28, wherein the power output from the second filter module is applied to the first modulator and an external device. 33. The single-cable transmission device according to claim 29, wherein the first demodulator and the second demodulator receive power input from outside. 34. The power output from the second filter module is applied to a first modulator, a second demodulator, and an external device.
0 single cable transmission device. 35. The single-cable transmission device according to claim 27, wherein the cable is a coaxial cable. 36. The single cable transmission device according to claim 27, wherein the baseband signal includes a video signal, an audio signal, and a control signal. 37. The single cable transmission device according to claim 27, wherein the electric power is DC electric power. 38. The single-cable transmission device according to claim 27, wherein the electric power is AC electric power. 39. The single cable transmission device according to claim 37, wherein the electric power has a voltage that changes according to a length of the single cable. 40. The single-cable transmission device according to claim 38, wherein the electric power has a voltage that changes according to the length of the single-cable. 41. The first modulator receives externally input electric power after rectification.
A single cable transmission as described. 42. The single-cable transmission device according to claim 38, wherein the power output from the second filter module is rectified and applied to the first demodulator and an external device. 43. The single cable transmission device according to claim 38, wherein the first modulator and the second demodulator receive externally input power after rectification. 44. The single cable transmission device according to claim 38, wherein the power output from the second filter module is rectified and applied to the first demodulator, the second modulator, and an external device. . 45. The modulation is coherent AM.
35. The method according to claim 27, characterized in that it is carried out in a manner.
A single cable transmission device according to any one of the above. 46. The single-cable transmission device according to claim 45, wherein the demodulation is performed by an AM detection method. 47. A single cable according to claim 27, wherein the modulation is performed in a non-coherent manner, the modulator further provided with an adder circuit for integrating the modulated carrier signal. Transmission device. 48. The method of claim 47, wherein the demodulation is performed in a phase locked loop (PLL).
A single cable transmission as described. 49. The single cable according to claim 27, wherein the first filter module and the second filter module include at least one band pass filter and one low pass filter. Transmission device. 50. The apparatus further includes a power voltage / output load status display device connected between the power output from the second filter module and the external device, and detects the power voltage and the operation status of the external device load. 35. The single-cable transmission device according to claim 32 or 34. 51. The single cable transmission device according to claim 50, wherein the power voltage / output load status display device includes a power voltage status detector, a load status detector, and a display module. 52. The power voltage condition detector and the load condition detector include at least one operational amplifier and one reference voltage, and the display module includes one decoder and an LED display device. 52. The single cable transmission of claim 51.