JP2003101813A - Method for automatically controlling gain and multi- channel repeater using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AGC controlling method for holding each channel signal to be amplified and outputted at a prescribed signal level in a repeater for collectively amplifying one signal consisting of a plurality of channel channels. SOLUTION: Each channel signal to be amplified and outputted is held at a prescribed signal level by adaptively changing the reference signal level of a control part for collectively amplifying one signal consisting of a plurality of channel signals, detecting the existence of each channel signal and generating an error signal for executing AGC in accordance with the number of input signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television signal relay device.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. FIG. 2 is a block diagram showing a configuration of a television relay device that receives one signal composed of signals of a plurality of channels, amplifies the received one signal to a predetermined level, and transmits the amplified signal. One signal composed of a plurality of channels is received by a receiving antenna (not shown) and input to the separation filter 2 via the input terminal 1. The separation filter 2 separates one input signal into signals for each channel, and the separated signals correspond to each channel. Single channel amplifier (CH-PA) 3-1, 3-2 ,. Output to 3-n respectively. Here, n is a positive integer and is the number of channels included in one received signal.

Each of the CH-PAs 3-1, 3-2, ..., 3-n has a predetermined level for transmitting the signal level of the input channel signal from a transmission antenna (not shown). Amplify to signal level and output to synthesis filter 4. These CH-PAs 3-1, 3-2, ..., 3-n operate in the same way for the signals of the corresponding channels.

The synthesizing filter 4 synthesizes the signals of the respective channels which have been amplified to a predetermined signal level, and synthesizes the signals of a plurality of channels into one signal.
Output to wideband multi-channel amplifier (MCPA) 5. MC
The PA 5 amplifies one input signal consisting of a plurality of channels to a predetermined level, outputs the amplified signal from the output terminal 7 to the transmission antenna via the output detection unit 6, and transmits the signal.

The output detector 6 detects the A
A comparison signal for GC (Automatic Gain Control) is extracted and
Output to GC section 8. The AGC unit 8 generates a control signal for automatically controlling the gain of the MCPA 5 according to the magnitude of the signal level of the comparison signal for AGC extracted from the output detection unit 6, and the gain of the MCPA 5 is controlled. Output to control terminal. MCP
A 5 controls the gain based on the control signal input to the gain control terminal, amplifies the signal input from the synthesis filter 4 to a predetermined signal level, and outputs it to the output terminal 7 via the output detector 6. To do.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the case of receiving one signal composed of a plurality of channels and amplifying the received one signal to a predetermined level and transmitting the signal, a certain channel is stopped due to, for example, the termination of television broadcasting in a television relay device or an accident. In the case of (discontinued), the signal level output from MCPA 5 automatically increases to the same signal level as when the signals of all channels are present by the automatic gain control of the AGC section. There was a drawback that the signal level of increased. An object of the present invention is to provide a relay device which eliminates the above-mentioned drawbacks and outputs while keeping the signal level of each channel at a predetermined signal level in accordance with the reception state of the signal of each channel. It is in.

[0007]

In order to achieve the above object, the relay apparatus of the present invention is a differential amplifier which detects the state of a received signal for each channel and generates an error signal for automatic gain control. By adaptively changing the signal level of a reference signal of a circuit or the like, the signals of the respective channels output from the MCPA 5 are collectively maintained at a predetermined signal level. Further, the present invention further controls the level of the reference signal to be lower or higher depending on the number of channels in which the signals have been interrupted among the received signals of a plurality of channels. In addition, the present invention further outputs a predetermined signal if it is determined that there is a received signal input, and outputs another predetermined signal if it is determined that there is no signal input, and outputs the comparison result of each channel. The reference signal is controlled by a signal obtained by replacing the predetermined signal from the above or another predetermined signal with another predetermined signal.

That is, the automatic gain control method of the present invention is a multi-channel relay which receives one signal composed of signals of a plurality of channels, amplifies the received one signal to a predetermined output signal level by a wide band amplifier, and transmits the amplified signal. A device for separating the received one signal into the signals of the plurality of channels, amplifying the separated signals of the plurality of channels by a plurality of single-channel amplifiers, and the amplified signals of the respective channels. In the automatic gain control method for synthesizing a single signal into a single signal, and controlling and outputting the synthesized single signal to the predetermined output signal level, the presence or absence of signal input is detected for each of the separated signals of a plurality of channels. The received signal by automatically controlling the gain of the wideband amplifier based on the presence or absence of the detected signal input. Characterized by amplifying a single signal to a predetermined output signal level.

The detection of the presence or absence of the signal in the automatic gain control method of the present invention is based on the assumption that the signal input of the corresponding channel is present when each of the separated signals of the plurality of channels is equal to or higher than a predetermined input signal level. When the input signal level is lower than the predetermined input signal level, there is no signal input to the corresponding channel. Further, the automatic gain control of the automatic gain control method of the present invention generates a reference signal based on the number of channels having the detected signal input or the number of channels not having the detected signal input, and sets the signal level of the reference signal. In addition, by automatically controlling the gain of the wideband amplifier, the received one signal is amplified to a predetermined output signal level. Furthermore, in the automatic gain control method of the present invention, the automatic gain control detects the output signal level of the output signal of the wide band amplifier, and the detected output signal level becomes the signal level of the reference signal. The received single signal is amplified to a predetermined output signal level by automatically controlling the gain of the wide band amplifier.

The multi-channel repeater such as the gap filler of the present invention is composed of signals of a plurality of channels.
A separation filter for receiving one signal and separating the received one signal into signals of a plurality of channels; and an amplifier corresponding to each of the plurality of channels for amplifying each of the separated signals of the plurality of channels to a predetermined signal level. A combining filter that combines the output signals of the amplifiers into one signal, a wide band amplifier that amplifies the combined signals, an output detection unit that detects the signal level of the output signal of the wide band amplifier, and the detected signal. An automatic gain control unit for controlling the gain of the wide band amplifier according to the output signal level, and multi-channel for amplifying and transmitting one received signal of the plurality of channels signals to a predetermined constant signal level. In the relay device, a signal detection unit that detects the presence or absence of a signal for each of the separated signals of the plurality of channels, A reference signal generation unit that generates a reference signal based on the presence or absence of the detected signal and outputs the reference signal to the automatic gain control unit, and changes and changes the predetermined constant signal level based on the reference signal. The received one signal is amplified to a predetermined output signal level by automatically controlling the gain of the wide band amplifier so as to obtain the predetermined constant signal level.

[0011]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a multi-channel signal 1
It is a block diagram which shows the structure of the television relay apparatus of one Example of this invention which receives one signal, amplifies the received one signal to a predetermined signal level, and transmits. The components having the same functions as the components described in FIG. 2 of the related art are assigned the same numbers. In FIG. 1, as in FIG. 2, one signal composed of a plurality of channels is received by a reception antenna (not shown), and separated through the input terminal 1 by the separation filter 2, CH-PA 3-1 and 3-2. , 3-n, CH-PA 3-1, 3-2, 3-n amplify each input channel signal and synthesize filter 4
The description is omitted because it is the same as in FIG. Also, CH-PA 3-1, 3-2, ..., 3-n perform the same operation for the signals of each channel.

The signal output from CH-PA 3-1 is supplied to the single-channel output detector (DET) 9-1. Less than,
Similarly, the signal from CH-PA 3-2 is supplied to DET 9-2, and the signal from CH-PA 3-n is supplied to DET 9-n. DET 9-1 is a synthesis filter for the input signal.
It is supplied to the reference signal generator 10 as well as supplied to the reference signal generator 4. Similarly, the DETs 9-2, ..., 9-n respectively supply the input signals to the synthesis filter 4 and output them to the reference signal generation unit 10.

The synthesizing filter 4 synthesizes the input signals of the respective channels and outputs it to the MCPA 5 as one signal composed of a plurality of channels. The MCPA 5 amplifies one input signal consisting of multiple channels to a predetermined signal level and outputs it via the output detector 6 to the output terminal.
Output from 7 to a transmitting antenna (not shown) for transmission.
The output detection unit (MDET) 6 extracts an AGC (Automatic Gain Control) comparison signal from the input signal and outputs it to the AGC unit 8 '. The AGC section 8'is the output detection section
A control signal for automatically controlling the gain of MCPA 5 is generated based on the magnitude of the signal level of the comparison signal for AGC extracted from 6, and is output to the gain control terminal of MCPA 5. The MCPA 5 controls the gain based on the control signal input to the gain control terminal, amplifies the signal input from the synthesis filter 4 to a predetermined signal level, and outputs it to the output terminal 7 via MDET 6.

The reference signal generator 10 includes DETs 9-1, 9-2,
‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ The number of channel signals is detected, or the number of stopped channels (wave stop number) of the signals of a plurality of channels is detected. In addition, this comparison process is performed by the CPU (Central proc
essing unit) or the like to perform appropriate arithmetic processing. Then, for example, a reference signal according to the number of wave stops is generated and output to the AGC unit 8 '. The AGC unit 8'performs automatic gain control so that the output signal of each of the remaining channels becomes a predetermined constant level according to the number of wave stops.

Various types of automatic gain control are conceivable, such as a combination of a comparator and a CPU, but this is not the essence of the present invention. Further, in the above-mentioned embodiment, the single-channel output detector is provided on the output side of the single-channel amplifier, but it is obvious that it may be anywhere between the separation filter and the synthesis filter.

[0016]

EFFECT OF THE INVENTION In a relay device which receives one signal composed of a plurality of channels, amplifies the received one signal to a predetermined level and transmits the signal, even if a certain channel is stopped, the remaining channels are It is possible to keep the signal at a predetermined signal level.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a television relay device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional television relay device.

[Explanation of symbols]

1: Input terminal, 2: Separation filter, 3-1, 3-2,
・ ・ ・, 3-n: Single channel amplifier (CH-PA), 4: Synthetic filter, 5: Wideband multi-channel amplifier (MCPA
), 6: Output detector, 7: Output terminal, 8, 8 ': AGC
Controller, 9-1, 9-2, ..., 9-n: Single channel output detector (DET), 10: Reference signal generator.

Continued front page    (72) Inventor Takahiko Nishizawa             1406 Hasunuma, Saitama City, Saitama Prefecture Hitachi, Ltd.             Kokusai Electric Omiya Factory F-term (reference) 5C056 FA01 FA05 GA02 HA01 HA04                 5K060 CC13 HH04 HH06 HH11 KK01                       KK03 KK04 LL01                 5K061 AA11 BB00 CC52                 5K072 AA01 BB14 BB27 DD16 EE20                       GG14 GG22 GG25 GG27

Claims (5)

[Claims] 1. A multi-channel relay device for receiving one signal composed of signals of a plurality of channels, amplifying the received one signal to a predetermined output signal level by a wide band amplifier, and transmitting the amplified signal. Separating one signal into the signals of the plurality of channels, amplifying the separated signals of the plurality of channels by a plurality of single-channel amplifiers, respectively, and combining the amplified signals of the respective channels into one signal; In the automatic gain control method for controlling and outputting one combined signal to the predetermined output signal level, the presence or absence of signal input is detected for each of the separated signals of the plurality of channels, and the detected signal input is detected. By automatically controlling the gain of the wideband amplifier based on the presence or absence of the received 1
An automatic gain control method comprising amplifying two signals to a predetermined output signal level. 2. The automatic gain control method according to claim 1, wherein the presence or absence of the signal is detected by inputting a signal of a corresponding channel when each of the separated signals of a plurality of channels has a predetermined input signal level or higher. If the input signal level is lower than the predetermined input signal level, it is determined that there is no signal input to the corresponding channel. 3. The automatic gain control method according to claim 1, wherein the automatic gain control is based on the number of channels with the detected signal input or the number of channels with no detected signal input. Generating a signal and automatically controlling the gain of the wideband amplifier so that the signal level of the reference signal is obtained, thereby amplifying the received one signal to a predetermined output signal level. Method. 4. The automatic gain control method according to claim 1, wherein the automatic gain control detects the output signal level of an output signal of the wide band amplifier, and detects the output signal level. Automatic gain control for amplifying the received one signal to a predetermined output signal level by automatically controlling the wide band amplifier so that the output signal level becomes the signal level of the reference signal. Method. 5. A separation filter for receiving one signal composed of signals of a plurality of channels and separating the received one signal into a signal of a plurality of channels, and a predetermined signal level for each of the separated signals of the plurality of channels. Amplifiers respectively corresponding to the plurality of channels that are amplified, a combining filter that combines the output signals of the amplifiers into one signal, a wide band amplifier that amplifies the combined signals, and a signal of the output signal of the wide band amplifier An output detection unit for detecting a level; and an automatic gain control unit for controlling the gain of the wide band amplifier according to the detected output signal level.
In a multi-channel relay device that amplifies one signal to a predetermined constant signal level and transmits the signal, a signal detection unit that detects the presence or absence of a signal for each of the separated signals of a plurality of channels, and a signal detection unit based on the presence or absence of the detected signal To generate the reference signal,
A reference signal generation section for outputting to the automatic gain control section, changing the predetermined constant signal level based on the reference signal, and automatically changing the wideband amplifier to the changed predetermined constant signal level. A multi-channel repeater, wherein the received one signal is amplified to a predetermined output signal level by gain control.