JPH03165611A - Two-way amplifier - Google Patents

Abstract

PURPOSE:To amplify signals with different transmission directions for each channel at one amplifier simultaneously and to make each modulator small in size and inexpensive by combining an amplifier section 6, two system of band pass filters and two systems of two pole switches. CONSTITUTION:The two-way amplifier is provided with an amplifier section 6, two systems of connection terminals 1, 3, two systems of band pass filters 2a-2e, 4a-4e, and two systems of two-pole switches 5a-5e, 7a-7e. A signal selected by the band pass filters 2a-2e, 4a-4e is inputted to the amplifier section 6 via the two-pole switches 5a-5e, 7a-7e closed at the input side of the amplifier section 6 and amplified with other signal inputted via the band pass filters 2a-2e, 4a-4e and the two-pole switches 5a-5e, 7a-7e and the amplified signal is selected and outputted via the two-pole switches 5a-5e, 7a-7e closed at the output side is the amplifier section 6 by the band pass filters 2a-2e, 4a-4e. Thus, signals with different transmission directions for each channel are amplified at one amplifier simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a bidirectional amplifier in a bidirectional information transmission system that bidirectionally transmits frequency-multiplexed RF signals of a plurality of channels.

BACKGROUND OF THE INVENTION Conventionally, coaxial home bus systems have been used as bidirectional information transmission systems. An example of the system configuration is shown in FIG. 3. In FIG. 3, the information outlet 31 is a completely bidirectional branching unit that exchanges baseband signals and RF multiplied signals between the transmission line and the terminal equipment. Modulators 32a and 32b C. Modulate the camera signal, R
It is output as F signal. Modulator 32a is a modulator that uses channel a, and modulator 32b is a modulator that uses channel b. The demodulators 33a and 33b demodulate the modulated RF signals and output the video signals to the monitor television 3.
4a.

34b. The demodulator 33a is a demodulator that demodulates channel a, and the demodulator 33b is a demodulator that demodulates channel b. Therefore, the monitor TV set 34a
An image from the camera 35a is displayed on the monitor 34b, and an image from the camera 35b is displayed on the monitor television 34b. The antenna 36 receives broadcast waves (VHF). The amplifier 37 amplifies the broadcast wave received by the antenna 36 and outputs it to the home bus. Between the complete bidirectional distributors, the VHF signal of the broadcast wave output from the amplifier 37 is divided into two and sent to both systems, and an RF multiplied signal demodulator 33a of channel a output from the modulator 32a is connected. The RF multiplied signal demodulator 33b of channel b output from the modulator 32b functions to flow the signal to the system connected to the system. The TV set 39 receives the broadcast waves received by the antenna 36 via the home bus, demodulates them with a built-in tuner, and displays TV programs.

Problems to be Solved by the Invention In order to satisfactorily receive a low-RF transmitted video signal, it is necessary to ensure a received signal level that is higher than the receiving sensitivity of the demodulator. For home bus systems, FM, VHF, U)
Broadcast waves such as iF, BS-IF, etc. are transmitted at their original frequencies, and subbands from 12 to 72 subbands or V)
iF, tJ) A vacant channel in the iF band is used to transmit a modulated RF signal such as a camera signal.

-The reception sensitivity of the demodulator used on a boat is 70dBμ in the subband band.
.

It is 65 dBμ in the V) iF and U) iF bands, and it is necessary to ensure a received signal level higher than this at the entrance of the demodulator.

On the other hand, various transmission losses occur in transmission paths such as information outlets, coaxial cables, and distributors, and the received signal level is obtained by subtracting the sum of various transmission losses from the output signal level of the modulator. Calculating using the specifications of home bus devices currently on the market, the output signal level Es of the modulator 32H necessary to ensure a signal level of 65 dBμ in the demodulator 33a is Es (dBμv) = asdBμ
v+information: ff:/-tF:/t Insertion loss (for 5 pieces) Sufficient information outlet branch loss (for 2 pieces) Sufficient distribution loss for distribution (for 1 piece) Ten coaxial cable loss (50 m) = 65 dB
μv + 15dB x 5 +13dB x 2 +
6.5dB 10t 5dH f-115dBμv is required. The output signal level of the modulator is determined by the capability of the amplifier in the output stage of the modulator, and the higher the output, the larger and more expensive the amplifier becomes. Furthermore, it is possible to connect up to eight sets of modulators to a home bus system, and it is unreasonable and uneconomical to provide each modulator with an amplifier. On the other hand, if one amplifier is connected to the home bus and all RF signals are amplified, the output level of each modulator can be small, but due to the nature of the home bus system, the signal transmission direction is bidirectional. Since the transmission direction for each channel is undefined, there have been no applicable amplifiers in the past.

The present invention solves the above conventional problem, and even if the transmission direction of the signal for each channel is undefined, the signal of each channel is amplified by one amplifier on the home path, and the output level of each modulator is The objective is to provide a bidirectional amplifier that can reduce the size of the signal.

Means for Solving the Problems In order to solve the above problems, the bidirectional amplifier of the present invention has R
an amplifier unit for amplifying the F signal; a first system connection terminal for connecting the first bidirectional transmission line; and one end connected to the first system connection terminal and selectively connected to the first bidirectional transmission line. niR
a first system bandpass filter for exchanging F signals; a common electrode is connected to the other end of the first system bandpass filter, and a first %1t& is connected to the output side of the amplification section; a 2m switch for the first system to which a second electrode is connected to the input side of the amplifier section, a second system connection terminal for connecting a second bidirectional transmission path, and a second system connection terminal to the second system connection terminal. a second system bandpass filter having one end connected thereto and passing the same frequency band as the first system bandpass filter for selectively exchanging RF multiplied signals with the second bidirectional transmission line; A common electrode is connected to the other end of the two-system bandpass filter, a first electrode is connected to the output side of the amplification section, and a second electrode is connected to the input side of the amplification section.
a second system two-pole switch to which an electrode of the second system is connected, and a second system two-pole switch to which an RF signal having a frequency located within the passband of the bandpass filter is input; 2t of the system on the side where the RF multiplied signal is output by pushing it to the pole side! ! ! The direction of the signal to be amplified is selected by moving one switch to the first electrode side.

Furthermore, in the bidirectional amplifier of the present invention, a plurality of pairs of first system bandpass filters and first system two-pole switches having mutually different pass bands are connected in parallel between the first system connection terminal and the amplifier section, Between the second system connection terminal and the amplifying section, a plurality of sets of a second system bandpass filter and a second system two-pole switch having the same pass band as the first system bandpass filter in item 60 are connected in parallel. , is configured to be able to amplify multi-channel signals with different transmission directions, and in addition to this, it also includes a switch drive unit for driving the two-pole switch for the first and second systems, and a baseband control signal. an interface unit that receives the baseband control signal and controls the switch drive unit, the interface unit receives the baseband control signal via the first system connection terminal or the second system connection terminal, and the interface unit receives the baseband control signal through the first system connection terminal or the second system connection terminal, and the interface unit receives the baseband control signal and controls the switch drive unit. According to the present invention, the switch driving unit is controlled to switch the two-pole switches for the first and second systems.

Operation With the above configuration, the signal selected by the bandpass filter is input to the amplification section via the two-pole switch closed on the input side of the amplification section, and the signal selected by the bandpass filter is inputted via the other bandpass filter and the two-pole switch. The amplified signal is amplified together with the signal, and the amplified signal is selected and outputted again by a bandpass filter via a two-way switch closed on the output side of the amplification section, so that signals with different transmission directions for each channel can be transmitted by one amplifier. can be amplified at the same time.

In addition, since the interface unit receives the baseband control signal and drives and controls the two-pole switches for the first and second systems via the switch drive unit, the transmission direction of the signal for each channel is automatically determined by the baseband control signal. will be controlled by.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a bidirectional amplifier showing a first embodiment of the present invention. In FIG. 1, the first system connection terminal 1 is connected to one end of the first system bandpass filters 2a to 2e, and the second system connection terminal 3 is connected to one end of the second system bandpass filter 4a to 4e. The passband is selected according to the frequency passband of the signal to be connected and amplified. The other ends of the band-pass filters 2a to 2e for the first system are connected to the common contacts of the two-pole switches 5a to 5e for the first system, respectively. The contacts are connected to the output end of the amplification section 6, and the respective second contacts are connected to the input end of the amplification section 6. Also, the second
The other ends of the system bandpass filters 4a to 4e are connected to the common contacts of the second system two-pole switches 7a to 7e, respectively, and
The contacts are connected to the output terminal of the amplifier section 6, and the respective second
The contact point is connected to the input end of the amplifier section 6. moreover,
Between the first and second system connection terminals 1.3, there is a bypass band-pass filter 8 that bypasses broadcast waves, etc., and a baseband low-pass filter 9 that bypasses baseband control signals such as on/off signals in home automation. connected, bypassing unnecessary signals on the home path. In this way, the bidirectional amplifier IO is constructed.

First and second system connection terminals 1.3 of bidirectional amplifier 10
have first and second bidirectional transmission paths, respectively.
and a second home path 12.13 are connected, and a plurality of information outlets 11 are interposed between the first and second home paths 12.13 to branch signals respectively. A monitor television 15a is connected to the information outlet 11 of the first home path 12 via a demodulator W 14a that demodulates channel a, and a modulator that uses channel b is connected to another information outlet 11. A camera 17b is connected via 16b. The information outlet 11 of the second home path 13 is connected to a camera 17a via a modulator 16a that uses channel a, and the other information outlet 11 is connected to a demodulator 4b that demodulates channel b. A monitor television 15b is connected through it.

The operation of the above configuration will be explained below.

The modulator 16a changes the video signal of the camera 17a and outputs it to the second system connection terminal 3 of the bidirectional amplifier IO via the second home bus 13 in the frequency band of channel a. Band pass filter 4a among band pass filters 4a to 4e
If the configuration is such that only the passband of channel a passes the frequency band of channel a, the signal of channel a is guided to the common N pole of the second system two-pole switch 7a. Now, since the second system two-pole switch 7a is turned to the second mb side connected to the input side of the amplifying section 6, the signal of channel a is input to the amplifying section 6, and the signal of channel a is input to the amplifying section 6. It is amplified and output.

At this time, if the two-pole switch 5a for the first system is set to the first electrode side, the amplified signal of channel a passes through the band filter 2a for the first system whose passband includes the frequency band of channel a. The signal flows to the first home bus 12 connected to the first system connection terminal 1 via the bus.

Here, the 1st (D [2 for the other 1st system leaning towards the pole side)
Pole switch 5d and second system two-pole switch 7b, 7
A band-pass filter 2d for the first system and a band-pass filter 4b for the second system connected to C and 7e, respectively.
, 4C, and 4e block the signal of channel a, so the signal of channel a does not flow from here. 1st home bus 1
The amplified channel a signal sent to the information outlet 11 is branched at the information outlet 11 and received by the demodulator 14a. The received signal is demodulated by a demodulator 14a and displayed on a monitor television 15a.

Similarly, the modulator 16b modulates the video signal of the camera 17b and outputs it to the first system connection terminal 1 of the bidirectional amplifier 10 via the first home bus 12 in the frequency band of channel b. The demodulator 14b of the second home path 1
In the bidirectional amplifier 10, channel a and channel b have different transmission directions. Even in this case,
The two-pole switch for the first system connected to the band-pass filter 2b for the first system whose pass band includes the frequency band of channel b is pushed to the second electrode side, and the band-pass filter 4b for the second system is connected to the second electrode side. When the two-pole switch 7b for the second system connected to is turned to the first electrode side, the amplifying section 6 amplifies the channel a as well as the channel b and sends the amplified signal to the second home path 13. Similarly, for channels C, d1 and channel e, the first system two-pole switches 5c and sa
, 5e and 2-pole switch 7C for the second system.

By moving 7d and 7e in an appropriate direction, all of them can be amplified by the amplifying section 6.

As described above, according to the first embodiment, by moving the two-pole switch in an appropriate direction, it is possible to amplify a plurality of signals transmitted in any direction with one amplification section. Furthermore, the passband and number of bandpass filters can be set arbitrarily.

FIG. 2 is a configuration diagram of an x-direction amplifier showing a second embodiment of the present invention. Components having the same functions and effects as those of the first embodiment are given the same reference numerals and explained. omitted. In FIG. 2, home bus system interface units (hereinafter referred to as IFLI) 21a, 21
b are connected between the information outlet 11 and the monitor television cabinets 15a and 15b, respectively, and are connected to the I F
[122a and 22b are modulators 16a and 16, respectively.
Connected between b and information outlet 11 further 1F
One end of the Uza is connected to the intermediate tap of the baseband low-pass filter 9, and it has a communication control function of transmitting and receiving baseband control signals composed of pulse codes via the home bus 12.13, and an interface function with terminal equipment. have. The signal detection circuits 24a and 24b are connected between the information outlet 11 and the IFUs 21a and 21b, respectively, and detect the presence or absence of the desired channel iM(7)kFi, and notify the IFIJ zxa and zlb. The switch drive unit 25 is connected between the other end of the IFU 23 and the two-pole switches 26a to 26e for the first system and the two-pole switches 271 to 27e for the second system.
23 and a two-pole switch 268 for the first system.
~26e and 2-pole switches 271-27 for the second system
Drive e. In this way, the bidirectional amplifier 28 is configured.

The operation of the above configuration will be explained below.

When the monitor television 15a becomes operational,
IFtJ21a connected to monitor TV code L5a
sends an activation message to I F IJ 2za connected to modulator 16a using a baseband control signal.

In response, I F U 22a activates modulator 16a. Then, a signal obtained by modulating the signal of camera 17a is sent out as channel a, but now
Assuming that the pole switches 268 to 26e and the two-pole switches 278 to 276 for the second system are tilted toward the side shown in FIG. and reaches the demodulator 14a. At this time, the signal detector 24a indicates that there is a signal.
Since IFU 2xa does nothing, channel a signal transmission continues.

Next, consider the case when the monitor television 15b enters the operating state. Similarly, l F LJ zlb is 1FU connected to modulator 16b by a baseband control signal.
The activation message is sent to 22b. In response, IFLI 22b activates modulator 16b.

Then, a signal obtained by modulating the signal of camera 17b is transmitted to channel b.
However, now the two-pole switch 2 for the first system
6a to 26e and second system two-pole switch 278 to 2
7e is sagging in the direction shown by the solid line in Figure @2, and 1
Then, the signal of channel b is not sent out to the second home path 13 and does not reach the demodulator 14b. At this time, the signal detector 24b notifies the I F U ztb that the signal is a flash signal, so that after a certain period of time the I F Ll zxb (I F Ll zxb)
The Ll 23 sends a message to the effect that the two-pole switch 26b for the first system and the two-pole switch 27b for the second system will be switched because there is no signal. The control switches the two-pole switch 26b for the first system and the two-pole switch 27b for the second system to the dotted line side in FIG. After that, the output of the signal detector 24b becomes 2 signals, so after a certain period of time I F U
At the time when 2tb senses the output of signal detector 24b, 1FLI 21b does nothing, and signal transmission of channel b continues.

Therefore, according to the second embodiment, the transmission direction is automatically set when a bidirectional amplifier is installed and when terminal equipment is relocated or expanded, thereby saving the labor of manual operation.

Effects of the Invention As described above, according to the present invention, signals having different transmission directions for each channel can be amplified simultaneously with one amplifier, and each modulator can be made smaller and cheaper. be.

Furthermore, the two-pole switches for the first and second systems can be driven and controlled by the baseband control signal, thereby automatically controlling the signal transmission direction for each channel.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a bidirectional amplifier showing a first embodiment of the present invention, FIG. 2 is a block diagram of a bidirectional amplifier showing a second embodiment of the present invention, and FIG. 3 is a block diagram of a conventional home bus FIG. 1 is a configuration diagram of a system. DESCRIPTION OF SYMBOLS 1... NS1 system connection terminal, 2a-2e... Band pass filter for 1st system, 3... 2nd system connection terminal, 4
a to 4e... Bandpass filter for second system, 5a to 5
e. 26a to 26e... 2-pole switch for the first system, 6...
・Amplification section, 7a to 7e, 27a to 27e...Two-pole switch for second system, 10, 28... Bidirectional amplifier,
n...lFU%5...Switch drive unit.

Claims (1)

[Claims] 1. An amplifying section for amplifying an RF signal, a first system connection terminal for connecting a first bidirectional transmission line, and a first system connection terminal having one end connected to the first system connection terminal and the first system connection terminal for connecting the first bidirectional transmission path; a first system bandpass filter for selectively exchanging RF signals with the first bidirectional transmission path; and a common electrode is connected to the other end of the first system bandpass filter, and the output of the amplifier section is connected to a common electrode. a second system for connecting a first system two-pole switch having a first electrode connected to the side thereof and a second electrode connected to the input side of the amplifying section, and a second bidirectional transmission path; a connecting terminal, and the second
a second system bandpass filter having one end connected to the system connection terminal and passing the same frequency band as the first system bandpass filter for selectively exchanging RF signals with the second bidirectional transmission path;
A common electrode is connected to the other end of the system band-pass filter and the second system band-pass filter, a first electrode is connected to the output side of the amplifier section, and a second electrode is connected to the input side of the amplifier section. and a two-pole switch for a second system to which an electrode is connected, and the two-pole switch of the system to which an RF signal of a frequency located within the passband of the bandpass filter is input is connected to the second electrode side. A bidirectional amplifier configured to select the direction of the signal to be amplified by turning the two-pole switch of the system on which the RF signal is output to the first electrode side. 2. A plurality of sets of bandpass filters for the first system and two-pole switches for the first system having mutually different pass bands are connected in parallel between the first system connection terminal and the amplifier, and the second system connection terminal and the amplification section are connected in parallel. A band-pass filter for the second system and a band-pass filter for the second system having the same pass band as the band-pass filter for the first system are installed between the parts.
A bidirectional amplifier configured to amplify multi-channel signals with different transmission directions by connecting multiple sets of pole switches in parallel. 3. A switch drive unit for driving the two-pole switch for the first and second systems, and an interface unit for receiving a baseband control signal and controlling the switch drive unit, and 2
The interface unit is configured to receive a baseband control signal via a system connection terminal, and control the switch drive unit according to the content of the baseband control signal to switch the two-pole switch for the first and second systems. The bidirectional amplifier according to claim 1.