JPS63299618A - Signal processor - Google Patents

Abstract

PURPOSE:To improve C/N by making an output signal supplied from respective channel processors to an active combiner into a signal to remove a noise and a spurious with a band pass filter in a channel processor. CONSTITUTION:A head end is composed of channel processors 81-816 constituted equally and an active combiner 9, the output signal of respective channel processors is supplied and mixed to the active combiner 9. The 81-816 have respectively a signal processing part 10, plural band pass filters 121-125 and a selecting means 14. When a certain channel signal is supplied to an input terminal 7 and this is frequency-converted to an F channel, the signal processing part 10 frequency-converts so that the frequency of the output signal can be the F channel. Simultaneously, the selecting switch of a BPF selecting part 42 in the selecting means 14 is operated, and the output signal of the signal processing part 10 is supplied through a selected band pass filter to an output terminal 33. Thus, to the active combiner 9, only the output signal of the F channel is supplied.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to signal processing used in the head end of a communal viewing and viewing device, etc., for example. Regarding tfi.

<Prior Art> Conventionally, there has been a head end as shown in FIG. 4, for example. This consists of n channel processors 2. ~2n and n bandpass filters4. ~4n
It is equipped with a mixing section consisting of. Each channel processor2. ~2° all have the same configuration, and are configured to be able to convert the input television signal into a television signal of another channel by adjusting the oscillation frequency of the built-in variable local oscillator. There is. That is, each channel processor 21-2 functions as a signal processing device. and 1, for example, a channel processor 2. converts the frequency of channel AI to channel al.

The frequency of the variable local oscillator is adjusted so that the channel processor 22 frequency-converts channel A2 to channel a2, and the channel processor 27 frequency-converts channel AN to channel an. . In addition, each bandpass filter 41
~4n passes the output signal of the connected channel processor (: has an I band. For example, the bandpass filter 41 has a passband that passes the channel al, and the bandpass filter 4□ has a passband that passes the output signal of the connected channel processor. A band pass filter 4 having a band for passing channel a2.
n has a band through which channel an is passed.

Each bandpass filter4. The output side of ~4o is output terminal 6
This output terminal 6 is connected to the main line of the communal viewing device. Note that 71 to 7n are input terminals of each channel processor 21 to 2n.

<Problems to be Solved by the Invention> In the head amplifier as described above, it may be necessary to change the frequency of the output signal of each channel processor to another frequency different from the current frequency. For example, channel processor 2° is currently frequency converting channel AI to channel al, but this is being converted into channel am, which has not been used by any channel processor until now.
6. It may be necessary to perform frequency conversion. In such a case, a bandpass filter 4. cannot be used as is, so it is necessary to change the passband of the bandpass filter 41 so that channel am can pass through. However, such a change in the channel am cannot be easily done in the location where the head amplifier is installed, so it must be taken back to the factory and adjusted again, or a separate channel am can be passed from the factory etc. I have to bring a bandpass filter, and at the location where this head amplifier is installed,
There is a problem in that the frequency of the output signal of each channel processor cannot be easily changed.

One way to solve this problem is to use an active combiner for each channel processor 2. It is also conceivable to mix ~2n output signals. However, active combiners
For the purpose of amplifying input signals of various frequencies, the output signal of each channel processor 2I to 2o has a wide band so as to cover the entire frequency band. Therefore, even noise that is not a signal that should be amplified is amplified.

Each channel processor 2. 2o is also configured to have a wide band because the frequency of the output signal can be varied as described above. Therefore, as shown in FIGS. 5(a) and 5(b), when the output signals of two channel processors whose noise level N and signal level S are equal but differ only in the output signal frequency are mixed by an active combiner, As shown in FIG. 4C, the noise level increases, resulting in a new problem of deterioration of the C/N ratio.

<Means for Solving the Problems> The purpose of the present invention is to provide a signal processing device that can improve the C/N ratio by several fractions, and for this purpose, the frequency of the output signal is selected from within a predetermined frequency range. a signal processing section configured to set the frequency as a frequency; a plurality of bandpass filters each having a passband corresponding to a different frequency band obtained by dividing the frequency range into a plurality of sections; and each of these bandpass filters and the signal processing section. and selecting means for supplying the output signal of the t-signal processing section to one of the band-pass filters that has a band through which the output signal of the signal processing section passes.

Effect> According to the present invention, the signal processing section generates an output signal of a frequency selected from within a predetermined frequency range. Then, the selection means supplies the output signal of the signal processing section to a bandpass filter having a passband through which the output signal can pass. Therefore, in the output signal of this bandpass filter, signals other than the output signal of the signal processing section, such as noise, are considerably attenuated. Therefore, even if the output signals of the signal processing device according to the present invention are mixed by an active combiner, C
/N ratio will not deteriorate.

<Effects> As described above, in the signal processing device according to the present invention, even if its output signals are mixed by the active combiner,
The C/N ratio does not deteriorate, and it is possible to take advantage of the advantage that no adjustment is required when the output signals of each signal processing device are mixed using an active combiner.

<Embodiment> In this embodiment, as shown in FIG. 2, the signal processing device according to the present invention is implemented in each channel processor 81 to 816 of the head end of a joint viewing device. The output signals of are supplied to an active combiner 9 and mixed. Each channel processor8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~12-. and selection means 14.

This signal processing section IO converts the frequency of the channel signal supplied to the input terminal 7 into a desired channel signal. The first local oscillation signal is mixed with the first local oscillation signal, frequency-converted to an intermediate frequency signal, and amplified.

This intermediate frequency signal is supplied to the processor section 20, where it is separated into a video signal and an audio signal, and after adjusting the signal levels of both signals, they are combined again.

Output. The purpose of performing such processing is to suppress noise. The output signal of the processor section 20 is supplied to the output amplifier section 22, where it is mixed with a second local oscillation signal from a second local oscillator 24, frequency-converted to an output signal, and amplified together. In addition, input amplifier section 1
6 and the output amplifier section 22 is an automatic gain control circuit 2.
6 is provided, and the gain of the input amplifier section I6 is controlled according to the signal from the output amplifier section 22.

The first local oscillator 18 and the second local oscillator 24 are both configured by voltage controlled oscillators, and the first local oscillator 18, together with the PLL control circuit 28 and the first frequency setting digital switch 30, has a PLLft configuration. The second local oscillator 24 constitutes a PLL together with the PLL control circuit 28 and the second frequency setting digital switch 32. Therefore, by operating the first frequency setting digital switch 30, the frequency of the first local oscillation signal can be changed, and similarly, by operating the second frequency setting digital switch 32, the frequency of the first local oscillation signal can be changed.
The frequency of the local oscillation signal can be changed. Therefore, the frequency of the first local oscillation signal is selected to convert the input channel signal into an intermediate frequency signal, and this intermediate frequency signal is converted into a frequency within a predetermined frequency range (for example, from the A channel to the T channel). By selecting the oscillation frequency of the second local oscillator 24 so that the frequency can be converted into an arbitrary channel signal, the signal processing unit IO converts the input channel signal into an arbitrary channel signal within a predetermined frequency range. It can be frequency converted and output.

Each bandpass filter 12. ~12-. have different passbands. For example, when the signal processing unit l outputs one of the output signals of a total of 20 channels from channel A to channel T, the first bandpass filter t
21 has a pass band through which channels A to D are passed, and a second band pass filter 122
The third band pass filter 12. has a pass band through which channels from the E channel to the H channel are passed. teeth,
The fourth bandpass filter 124 has a passband that passes from the T channel to the L channel, the fourth bandpass filter 124 has a passband that passes the M channel to the P channel, and the fifth bandpass filter 124 has a passband that passes the T channel to the L channel. are each configured to have a pass band that passes from the Q channel to the T channel.

The selection means 14 includes an output amplifier section 22 and each bandpass filter 12. -12s input side PIN diode 34. ~34%, and each bandpass filter 121~12. and the output side PIN diode provided between the output terminal 33 and the 361 to 36%
have. Input side PIN diode 34. and output side PIN diode 36. and the anodes are respectively high frequency blocking chokes: I8. ．． 40. 6) is connected to the first output side of the pass filter selection section 42, and the input side PI
The anodes of the N diode 34□ and the output side PIN diode 362 are connected to the high frequency blocking choke 38. ．． 40
2 is connected to the second output side of the bandpass filter selection section 42 through the input side PIN diode 34.
5 and the output side PIN diode 36S are connected to the fifth output side of the bandpass filter selection section 42 via high frequency blocking chokes 38a and 405, respectively. The bandpass filter selection section 42 has five selection switches (not shown), and when the first selection switch is operated, a signal is generated on the first output side, and the input side PIN diode: 1
4. ．． 36. conduction, and the output signal of the signal processing unit IO is.

Bandpass filter +2. is supplied to the output terminal 33 via. Similarly, when the fourth selection switch is operated, a signal is generated on the fourth output side and the input side PIN diode 34
4.364 becomes conductive, and the output signal of the signal processing unit IO is supplied to the output terminal 33 via the bandpass filter 124. The same applies when other selection switches are operated.

Note that 44, 44, . . . are bypass capacitors.

In the channel processor configured in this way, for example, when a channel signal is supplied to the input terminal 7 and is frequency-converted to an F channel, the frequencies of the first local oscillation signal and the second local oscillation signal are converted to the output signal. Select the frequency so that it becomes the F channel. At the same time, the second selection switch of the bandpass filter selection 1142 is operated to supply the output signal of the signal processing section IO to the output terminal 33 through the second bandpass filter 122. With this, 1. The active combiner 9 is supplied with only the F channel output signal 5''f, and the noise is removed by the I1 band pass filter +2.
The spurious of is also removed by the band pass filter +22.

In this state, if it becomes necessary to change the output signal of one signal processing unit from the F channel to the A channel, the oscillation frequency of the second local oscillation signal is changed so that the output signal becomes the A channel, and at the same time, the The first selection switch of the pass filter selection section 42 is operated. by this,
The A channel output signal of the signal processing unit IO is supplied to the output terminal 33 via the bandpass filter 121. Even in this state, noise is removed by the bandpass filter 12. At the same time, the spurious of the F channel output signal is also removed by the band pass filter 12. will be removed.

Each channel processor8. The channel signals supplied to each channel processor 8,6 are of different frequencies, and each channel processor 8. The output signal of ~8.6 is
These are different channel signals among channels A to T.

Each of these channel signals is supplied to an active combiner 9. As shown in FIG. 3, this active combiner 9 has six irises with one branch 7446. ~4616 and 3
It consists of two 2-way dividers 48, 50, 52 and one wide range amplifier 54. 1 branch each 46. ~46,6 branch terminals are connected to each channel processor 8. Terminal 56 on the output side of ~8,6. ~5616. 1 each
Turnout 46. The input terminals and output terminals of 464 and 464 are connected in cascade, and the input terminals of 1 branch 46. The output terminal of is connected to the dummy resistor 58, and the input terminal of the 1-brancher 464 is connected to one distribution terminal of the 2-divider 48. 1 branches 465 to 468 are similarly connected in cascade, and 1 branch 3!46
．． The output terminal of the divider 455 is also connected to the dummy resistor 58, and the input terminal of the 1-brancher 455 is also connected to the other distribution terminal of the 2-divider 48. The 1-branchers 469 to 46.6 are similarly connected to the dummy resistor 58 and the 2-divider 50. The input terminals of these two-way dividers 48 and 50 are connected to both distribution terminals of the two-way divider 52, respectively. The input terminal of this two-way divider 52 is connected to a wide band width filter 54 . This active combiner 9 includes 1 branching device 465 to
46, 6.2 Distribution rA48.50.52 utilizes the fact that when a signal is input from the branch terminal or distribution terminal, it is difficult to reverse the flow to the output terminal side, and the signal supplied to the output terminal flows to the input terminal side. This is used as a type of directional coupler, and each terminal 56. Channel processor 8. input from ~56,6. -816 produces its output signal at the input side of each one-way splitter 46S-46.6, and is applied to the output side of the adjacent one-way splitter 465-46a. In this way, the output signal of each channel processor 21 to 2.6 is supplied to a 2-way divider 48.50, from which it is supplied via a 2-way divider 52 to a broadband amplifier 54, where it is amplified and sent to an output terminal 60. via the main line of the joint viewing and viewing equipment. In this case, each branch base is 46. ~46a and the 2-way divider 48, 50, 52 are configured to have a wide band so that they can pass signals from the A channel to the T channel, and the wide band amplifier rA54 is also configured to have a wide band. As shown in the broadband amplifier 54
Noise is also caused by the 1 splitters 465 to 4616 and the 2 splitters 48.
50.52, which is also amplified.

FIG. 5(d) shows the output when the outputs of the two channel processors configured as shown in FIG. 1 are supplied to the active combiner 9, and as is clear from the comparison with FIG. Additionally, by using a channel processor implementing the present invention, the C/N ratio can be improved.

In the embodiment of L, the number of channel processors is 16.
However, this number can be changed arbitrarily.

Furthermore, although the number of channels that can frequency-convert an input signal with one channel processor is set at 20, this number can also be changed arbitrarily. Furthermore, in the above embodiment, the channel processor converts the frequency of the input signal and outputs it, but after converting the input signal to a signal of a different frequency and processing it in the processor section 20, Again, it is also possible to use a structure that converts the frequency to the same as that of the input signal. Furthermore, the selection means includes an output side PIN diode 36. 365 are provided, but these may be removed and the output side of each bandpass filter may be connected directly to the output terminal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a signal processing device according to the present invention, FIG. 2 is a block diagram of a head end of a joint viewing device using the same embodiment, and FIG. 3 is a block diagram of a head end used in the head end of FIG. Figure 4 is a block diagram of a conventional active combiner, and Figures 5 (a) and (b) are block diagrams of a conventional head end.
) is a frequency characteristic diagram of the channel processor used in the head end in Figure 4, Figure 5 (C) is a frequency characteristic diagram of the active combiner of the channel processor in Figure 4, and Figure 5 (d) is the frequency characteristic diagram of the active combiner of the 2nd UA. FIG. 10...signal processing section, 12. ~12. ... band pass filter, 14... selection means. Patent applicant: D-X Antenna Co., Ltd.
Tetsu Shimizu Haka 2 Masters 1 (21 Fang 3 Figures 4 Figures 2 J7 'An Little 5 Figures (a)<b) (C) (,/) Procedure Neichi J13 J12 (Voluntary) 1986 IJ15 [1 Mr. Kunito Ogawa, Commissioner of the Japan Patent Office 1 Indication of Patent Application No. 136509/1982 2 Name of Issue II Headend 3 Person making the amendment Relationship with the issue Name of patent applicant Diex Antenna Co., Ltd. 4 Agent postal code 651 Address 111-113 Kumoidori 7-chome, Chuo-ku, Kobe Address Same as above Name (6229) Masashi Shoji Mei 4-, convex-- 2: Volume 5 Subject of amendment - "Title of the invention", specification ``Claims'', ``Detailed Description of the Invention'', ``Brief Description of Drawings'' sections and drawings. 6 Contents of amendment (+) The name of the invention is corrected to "Head End". (2) Amend the specification as shown in the attached sheet. (3) Replace Figures 1 and 4 of the drawings with those on separate sheets. Attached Category 3 Amended Specification Drawings Figures 1 and 4 Amended IJ1 Detail 1g l Name of the Invention Head End 2, Claim 3 Detailed Description of the IJI (Industrial Application Field) This invention is based on the following: Concerning headends such as joint viewing and viewing equipment. <Prior Art> Conventionally, the above-mentioned hardware has been as shown in FIG. 4, for example. This consists of n frequency converters 2.
2n and a mixing section consisting of n bandpass filters 41 to 4o. Each frequency converter 21 to 2
．． ．． They all have the same configuration, and by adjusting the oscillation frequency of the built-in variable local oscillator, the input television signal is frequency-converted to the television signal of another channel, and then amplified. It is configured. For example, the frequency converter 21 frequency converts channel AI to channel al, the frequency converter 22 frequency converts channel A2 to channel a2, etc. Frequency conversion? ! The frequency of the variable local oscillator 12n is adjusted to convert the frequency of channel AN into channel an, respectively. Furthermore, each of the bandpass filters 4I to 4n has a relatively narrow passband that allows only the output signal of the connected frequency converter to pass therethrough. For example, bandpass filter 4I
has a pass band that allows only channel al to pass, band pass filter 4□ has a band that allows only channel a2 to pass,...Band pass filter 4n has
It has a band that allows only channel an to pass. The output side of each bandpass filter 41 to 4n is connected to an output terminal 6, and this output terminal 6 is connected to the main cable of the communal viewing device. In addition, 71-7n are each frequency conversion part 2. ~2n input terminal. <Problem to be solved by the invention> In the headend as described above, it may be necessary to change the frequency of the output signal of each frequency converter to another frequency different from the current frequency. Currently, the frequency converter 2I is frequency converting the channel AI to the channel al, but it may become necessary to frequency convert this to the channel am, which has not been used by any frequency converter so far. In such a case, bandpass filter 4 cannot be used as is, so bandpass filter 4. Is it necessary to change the passband of the channel so that it can pass channel am? However, such a pass band change cannot be easily done because the head end is installed at the location where the head end is installed, so it must be taken back to the factory and adjusted again, or a new band pass filter that can pass channel AM from the factory etc. There was a problem in that the frequency of the output signal of each frequency conversion section could not be easily changed at the location where the head end was installed. <Means for Solving the Problems> An object of the present invention is to provide a head end that solves the above problems. Therefore, the present invention provides a head end that solves the above problems. It consists of a processing device and an active combiner to which the output signals of these signal processing devices are supplied. Each signal processing device includes a signal processing unit configured to transmit an input signal as a frequency selected from within a predetermined frequency range, and a passband for each frequency band obtained by dividing the frequency range into a plurality of frequencies. a plurality of band-pass filters interposed between each of these band-pass filters and the signal processing section, and one of the band-pass filters having a band that passes the output signal of the signal processing section; and selecting means for supplying the output signal of the processing section. Further, the active combiner includes a combination circuit including a plurality of branchers and a plurality of distributors, and a wideband amplifier connected to the combination circuit. <Operation> According to the present invention, the signal processing section of the signal processing device sends out an input signal as an output signal of a frequency selected from within a predetermined frequency range. Then, the selection means supplies the output signal of the signal processing section to a bandpass filter having a passband through which the output signal passes. Therefore, the output signal of this bandpass filter is a signal other than the output signal of the signal processing section,
For example, noise and spurious signals are significantly attenuated. The signals from the selected bandpass filters of each signal processing device are mixed in an active combiner and sent out. When changing the frequency of the output signal of each signal processing device, the band pass filter to be used is changed by the selection means. In such a case, since the active combiner consists of a splitter, a divider, and a wideband amplifier, no adjustment is necessary. Effect> As described above, in the head end according to the present invention, when changing the frequency of the output signal of the signal processing device, the active combiner is composed of a brancher, a divider, and a wideband amplifier. No adjustment is required; all you have to do is switch the bandpass filter to be used using the selection means of the signal processing device.
Since there is no need to replace filters, the frequency of the output signal can be changed immediately. Moreover, since the active combiner includes a wideband amplifier, noise and spurious signals are also amplified (or perhaps the bandpass filter in the signal processing device attenuates noise and spurious signals). , these signals sent from the active combiner are very small and pose no problem at all. <Example> This example uses channel processors 8. to 8.6 and an active combiner 9 as shown in FIG. The output signal of each channel processor 8. to 8.6 is
It is supplied to an active combiner 9 and mixed. Each of the channel processors 81 to 8, 6 has the same configuration, and as shown in FIG.
A plurality of bandpass filters 12. ~125 and 7 selection steps 1
4. This signal processing section IO converts the channel signal supplied to the input terminal 7 into a desired channel signal by 1.1 wave number. It is mixed with the first local oscillation signal from the local oscillation signal 8, frequency-converted to an intermediate frequency signal, and amplified. This intermediate frequency signal is supplied to the processor section 20, where it is separated into a video signal and an audio signal, and after adjusting the signal levels of both, they are combined again. Output. The purpose of performing such processing is to suppress noise. The output signal of the processor section 20 is supplied to the output amplifier section 22, where it is mixed with a second local oscillation signal from a second local oscillator 24, frequency-converted into an output signal, and amplified. In addition, input amplifier section 1
6 and the output amplifier section 22, there is an automatic gain control circuit (
AGC) 26 is provided, and the gain of the input amplifier section 16 is controlled according to the signal from the output amplifier section 22. The first local oscillator 18 and the second local oscillator 24 are both constituted by voltage controlled oscillators, and the first local oscillator 18 is configured by a PLL control circuit 28 and a first frequency setting digital switch 30. The second local oscillator 24, together with the PLL control circuit 28 and the second frequency setting digital switch 32, constitutes a PLL. Therefore, by operating the first frequency setting digital switch 30, the frequency of the first local oscillation signal can be changed, and similarly by operating the second frequency setting digital switch 32, the frequency of the first local oscillation signal can be changed.
It is possible to change the frequency of the second local oscillation signal. Therefore, the frequency of the first local oscillation signal. Select a manually input channel signal to be converted to an intermediate frequency signal, and convert this intermediate frequency signal to any channel signal within a predetermined frequency range (for example, from A channel to T channel). By selecting the oscillation frequency of the second local oscillator 24, the signal processing unit 10 can frequency-convert the input channel signal into an arbitrary channel signal within a predetermined frequency range and output it. Ru. Each bandpass filter 12. . . . 125 have different passband widths. For example, when outputting one of the output signals of a total of 20 channels from the signal processing 110 to the A channel to the T channel, the first bandpass filter 12 . The second bandpass filter 122 has a relatively wide passband width that allows channels from the A channel to the D channel to pass through, and the second bandpass filter 122 has a relatively wide passband width that allows the channels from the E channel to the H channel to pass. And the third
The bandpass filter 123 of the fourth bandpass filter 12. has a wide passband width that passes from the L channel to the L channel. has a relatively wide pass band width that passes from the M channel to the P channel, and the fifth band pass filter +2° has a relatively wide pass band width that passes from the Q channel to the T channel. Each of them is configured as follows. The selection means 14 includes an output amplifier section 22 and each of the bandpass filters IL to 12. input side PIN diodes 341 to 345 provided between the input side of each bandpass filter 12 . ~12. and output terminals 36□ to 365, respectively, provided between the output terminal and the output terminal. Input side PIN diode 34, and output side PIN
Diode 36. and the anodes of the high frequency blocking choke 38. ．． 40. The anodes of the input-side PIN diode 34□ and the output-side PIN diode 362 are connected to the first output side of the band-pass filter selection section 42 via the high-frequency blocking fix choke 382, 40□, respectively1). Castle passing filters 12, ~12. 2nd selection part
The anodes of the input side PIN diode 345 and the output side PIN diode 365 are respectively connected to the output side of the high frequency blocking choke 38. ．． ．． 4o5 to the fifth output side of the bandpass filter selection section 42. The bandpass filter selection section 42 has five selection switches (not shown), and when the first selection switch is operated, a signal is generated on the first output side, and the input side PIN diode 34. , :16. The output signal of the signal processing section In is passed through a band pass filter.12. through the output end T
-33. Similarly, when the fourth selection switch is operated, a signal is generated on the fourth output side, and the input side PIN
Diode 34. , 36. is conductive, and the output signal of the signal processing section 10 is passed through the band pass filter 12. It is supplied to the output terminal -f33 via. The same applies when other selection switches are operated. Note that 44, 44, . . . are bypass capacitors. For example, when a channel signal is supplied to the input terminal 7 and is frequency-converted to an F channel, the channel processor configured in this manner outputs the frequencies of the first local oscillation signal and the second local oscillation signal. Select the signal frequency or F channel. At the same time, operate the second selection switch of the bandpass filter selection section 42,
The output signal of the signal processing unit IO is passed through the second band pass filter 1.
It is supplied to the output terminal 35 through 2□. by this,
Only the F channel output signal is supplied to the active combiner 9, and unnecessary noise in other frequency bands is removed by the band pass filter 12□.In addition, the spurious of the F channel output signal is also removed by the band pass filter 122. removed. In this state, if it becomes necessary to change the output signal of the signal processing unit IO from the F channel to the A channel, the oscillation frequency of the second local oscillation signal is changed so that the output signal becomes the A channel, and at the same time, The first selection switch of the bandpass filter selection section 42 is operated. by this,
The A channel output signal of the signal processing unit 10 is supplied to the output terminal r-33 via the band pass filter 12°. Even in this state, the noise is reduced by the bandpass filter +2. At the same time, the spurious of the F channel output signal is also removed by the band pass filter 12. removed. Each channel processor8. The channel signals supplied to the processors 81 to 816 have different frequencies, and the output signals of the channel processors 81 to 816 are as follows:
Output channels 0 and 0 are different from each other among channels A to T. Each of these output channel signals is supplied to an active combiner 9. This active combiner 9
As shown in the figure, 16 1-branchers 46, 46, 6,
It consists of three 2-way dividers 48, 50, 52 and one broadband amplifier 54. 1 branch each 46. ~461. The branch terminals of each channel processor 8. ~816 via terminals 561~56.6. 1 each
Turnout 46. The input terminals and output terminals of 464 and 464 are connected in cascade, and the input terminals of 1 branch 46. The output terminal of the 1-brancher 46 is connected to the tammy resistor 58, and the input terminal of the 1-brancher 46 is connected to one distribution terminal of the 2-divider 48. The 1-branchers 465 to 468 are also connected in cascade, and the 1-brancher 46
The output terminal of No. 8 is also connected to the dummy resistor 58, and the input terminal of the 1st branch base 465 is also connected to the other distribution terminal of the 2nd divider 48. The 1-branchers 469 to 46.6 are similarly connected to the dummy resistor 58 and the 2-divider 50. The input terminals of these two-way dividers 48 and 50 are connected to both distribution terminals of the two-way divider 52, respectively. The input terminal of this two-way divider 52 is connected to a wideband amplifier 54. This active combiner 9 has one branching unit 461 to 4
6I6.2 distributor 48.50.52 etc. are reversely coupled, so when a signal is input from the branch terminal or distribution terminal, it is difficult for the signal to flow back to the output terminal side of the distributor or branch, and it is not supplied to the output terminal. 1 branchers 461 to 4616.2 distributors 48.5
0.52 as a type of directional coupler, each branch terminal 56. The output signals of the channel processors 81 to 816 inputted from ~5616 are sent to one brancher 461~
The output signal is generated at the input end of 46.6 by the amount of branching loss, and is applied to the output side of the adjacent one-brancher 46° to 46.6. In this way, each channel processor 8.
The output signal of ~816 is fed to a two-way divider 48.50,
The signal is then fed via a two-way splitter 52 to a broadband amplifier 54, where it is amplified and fed via an output terminal 60 to the mains cable of the communal viewing system. In this case, each 1-brancher 46° to 46o and 2-brancher 48, 50, 52 are as follows:
It is configured to have a wide band so that signals from the A channel to the T channel can be passed, and the wide band amplifier 54
is also configured to have a wide band. Therefore, the output signals from each channel processor 81 to 816 can be adjusted even if the frequency of the output signal of each channel processor is changed or without any adjustment of the active combiner 9.
The active combiner 9 mixes the signals and sends them out to the trunk cable. When the active combiner 9 is used as a mixing section in this way, even if the frequency of the output signals of the channel processors is changed, the output signals of each channel processor can be mixed without adjustment and sent to the main cable. Therefore, the fourth
In the conventional device shown in the figure, it is also conceivable to use an active combiner in place of each of the bandpass filters 41 to 4n. However, the active combiner has a function of amplifying input signals of various frequencies and outputting the amplified signals. The frequency band is wide enough to cover the entire frequency band of the output signal of ~2o. Furthermore, each of the frequency converters 21 to 2o is also capable of varying the frequency of the output signal, and the built-in amplifiers are also configured to have a wide band. Therefore, as shown in FIGS. 5(a) and 5(b), when the output signals of two frequency converters whose noise level N and signal level S are equal and whose output signals differ only in frequency are mixed by an active combiner, As shown in FIG. 2C, the noise level increases, and as a result, the C/N ratio deteriorates. Moreover, since it has a wide band, spurious signals output from each frequency conversion section are also amplified. However, in this embodiment, the output signals supplied to the active combiner 9 from the channel processors 8I to 8.6 are noise-removed by the band-pass filters in the channel processors 81-8.6, and spurious signals are also removed. Therefore, even if multiple sets of narrowband bandpass filters are not used in the mixing section, the C
/N ratio can be obtained, and spurious can be suppressed to the same extent. FIG. 5(d) shows the output when the outputs of the two channel processors configured as shown in FIG. 1 are supplied to the active combiner 9, and from a comparison with FIG. It is clear that the /N ratio can be improved. In the above example, the number of channel processors is 16.
This number can be changed arbitrarily. Furthermore, although the number of channels that can frequency-convert an input signal with one channel processor is set at 20, this number can also be changed arbitrarily. Further, in the embodiments described above, the channel processor is shown as one that converts the frequency of the input signal and outputs it, or converts the input signal once into a signal of a different frequency and then outputs the signal. It is also possible to use a configuration in which the processor section 20 processes the signal and converts it back to the same frequency as the input signal. Furthermore, the selection f stage has an output side PIN diode 36. ~
365 may be provided or eliminated, and the output side of each bandpass filter may be connected directly to the output terminal. 4. Brief description of the drawings Fig. 1 is a block diagram of a signal processing device used in one embodiment of the head end device according to the present invention, Fig. 2 is a block diagram of the same embodiment, and Fig. 3 is a block diagram of the signal processing device used in the same embodiment. Figure 4 is a block diagram of the conventional active combiner, Figure 5 (a) and (b) are frequency characteristic diagrams of the channel processor used in the head end of Figure 4, Figure 5 (C ) is a frequency characteristic diagram of the output of the active combiner when the output of the frequency conversion section of FIG. 4 is supplied to the active combiner, and FIG. 5(d) is a frequency characteristic diagram of the output of the active combiner of FIG. 2. 8, ~816...Channel processor (signal processing device), 9...Active combiner, 1 port...
- Signal processing section, +2. ~12. ...Band pass filter, M----selection f one stage, 4L "-46+s"" splitter, 48.5o, 52...Distributor, 54...
Broadband amplification.

Claims (1)

[Claims] (1) A signal processing unit configured to set the frequency of an output signal to a frequency selected from within a predetermined frequency range, and a plurality of signal processing units configured to divide the frequency range into a plurality of frequency bands, each of which has a pass band. and a bandpass filter interposed between each of these bandpass filters and the signal processing section, and one of the bandpass filters having a band for passing the output signal of the signal processing section, and the output of the signal processing section. A signal processing device comprising: selection means for supplying a signal.