JP3044215B1 - Antenna shared equipment - Google Patents

Abstract

An antenna duplexer that supplies a transmission wave of an adjacent channel to an antenna reduces an insertion loss of each transmission wave and reduces an in-band amplitude deviation of each transmission wave. SOLUTION: A first filter group that passes transmission waves of even-numbered (or odd-numbered) channels, and transmission of odd-numbered (or even-numbered) channels respectively connected in cascade to the first filter group. An antenna sharing apparatus comprising at least a second group of filters for transmitting waves, wherein the first group of filters includes a plurality of constant impedance bands for transmitting transmission waves of even-numbered (or odd-numbered) channels. A pass filter is formed by cascade connection, one of the plurality of cascade-connected constant impedance band-pass filters is connected to the second filter group, and the other is connected to an antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna sharing apparatus, and more particularly to a technique effective when a plurality of transmitters share a transmitting antenna in a VHF or UHF band television broadcasting mechanism.

[0002]

2. Description of the Related Art FIG. 17 is a diagram showing an example of an array of channels used in a conventional analog television broadcast, and FIG. 18 is a diagram showing a conventional antenna when the channels used are the array shown in FIG. FIG. 2 is a block diagram illustrating a schematic configuration of a shared device. As shown in FIG. 18, in the conventional antenna sharing device, the second terminal (T) of each adjacent first hybrid circuit (H13a, H15a, H23a) is used.
b) and the first terminal (Ta) are connected to each other, and the first terminal of the first hybrid circuit (H13a) at both ends is connected.
Terminal (Ta) is connected to the non-reflection terminator (R), and the second terminal (Tb) of the first hybrid circuit (H23a) at both ends is connected to the antenna (ANT). The third hybrid circuit (H13a, H15a, H23a)
(Tc) and each second hybrid circuit (H13
b, H15b, H23b) and bandpass filters (B13a, B15a, B23a) for transmitting transmission waves of predetermined channels are connected between the third terminals (Tc) of the first hybrid circuits, respectively. (H13a, H15
a, H23a) and the fourth terminal (Td) of each of the second hybrid circuits (H13b, H15b, H23b) transmit a transmission wave of a predetermined channel. Bandpass filters (B13b, B15
b, B23b) are connected. Further, a first terminal (Ta) of each second hybrid circuit (H13b, H15b, H23b) is connected to a transmitter that outputs a transmission wave of each channel, and each second hybrid circuit (H1b)
3b, H15b, H23b) have a second terminal (Ta)
Each is connected to a reflectionless terminator (R).

Here, each of the first and second hybrid circuits and each band-pass filter constitute a constant impedance band-pass filter that allows transmission waves of each channel to pass. That is, the first hybrid circuit (H13
a), the second hybrid circuit (H13b), and the band-pass filters (B13a, B13b) are a constant-impedance band-pass filter that allows the transmission waves of 13 channels to pass therethrough, using the first hybrid circuit (H15a), The hybrid circuit (H15b) and the band-pass filters (B15a, B15b) include a constant-impedance band-pass filter that allows transmission waves of 15 channels to pass, a first hybrid circuit (H23a), and a second hybrid circuit (H23b). ) And the band-pass filters (B23a, B23b) constitute a constant-impedance band-pass filter that allows transmission waves of 23 channels to pass.

[0004] The operation of the antenna sharing apparatus shown in FIG. 18 will be briefly described below by taking transmission waves of 13 channels as an example. In the antenna sharing apparatus shown in FIG. 18, the transmission waves of 13 channels input from the first terminal (Ta) of the second hybrid circuit (H13b) respectively pass through the band-pass filters (B13a, B13b) and The first hybrid circuit (H13a) is input to the first hybrid circuit (H13a) and is output from the second terminal (Tb) of the first hybrid circuit (H13a). The 13-channel transmission waves output from the first hybrid circuit (H13a) are input to the first hybrid circuit (H15a), and are transmitted to the band-pass filter (B15).
a, B15b) and is totally reflected and output from the second terminal (Tb) of the first hybrid circuit (H15a). Hereinafter, similarly, the light reaches the antenna (ANT) and is radiated from the antenna (ANT).

[0005]

In a conventional analog television broadcast, as shown in FIG. 17, there is ample available channels, and at the same time, the spurious condition also depends on the video signal carrier (f _V ) and the audio signal. Carrier (f _A ),
It is determined by the chrominance subcarrier. Therefore, the band-pass filters (B13a, B13a) used in FIG.
b, B15a, B15b, B23a, B23b) are gently designed, and the band-pass filters (B13a, B13a,
B13b, B15a, B15b, B23a, B23b)
As a result, a bandpass filter having a gradual selection characteristic (or cutoff characteristic) can be used. On the other hand, in recent years, in addition to the conventional analog television broadcasting, digital television broadcasting is about to be started due to technological advances. However, when digital television broadcasting is transmitted in addition to analog television broadcasting, digital television broadcasting-digital television broadcasting, There is a need for television broadcasting using adjacent channels, such as television broadcasting of a system-digital television broadcasting.

FIG. 19 is a diagram showing an example of a used channel arrangement in television broadcasting using such adjacent channels. FIG. 20 is a block diagram showing a schematic configuration of an antenna duplexer devised by the present inventors before the present application when the channels used are the arrangement shown in FIG. The antenna duplexer shown in FIG. 20 has a first terminal (T) of a second hybrid circuit (H14b, H15b, H22b).
Since the transmission wave input from a) is different from the antenna duplexer shown in FIG. 18 only in that the transmission wave is a transmission wave of an adjacent channel, a detailed description thereof will be omitted. However, the antenna duplexer shown in FIG. 20 has bandpass filters (B14a, B14b, B15a, B15b, B22).
a, B22b), the transmission characteristics and the reflection characteristics overlap, and there is a problem that the insertion loss of the transmission wave supplied to the antenna (ANT) and the in-band amplitude deviation increase. The present invention has been made in order to solve the problems of the prior art, and an object of the present invention is to reduce the insertion loss of each transmission wave in an antenna duplexer that supplies a transmission wave of an adjacent channel to an antenna. It is another object of the present invention to provide a technique capable of reducing the in-band amplitude deviation of each transmission wave.
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, according to the present invention, a first filter group having a plurality of constant impedance band-pass filters that pass transmission waves of even-numbered (or odd-numbered) channels, respectively, and cascade-connected to the first filter group,
A second filter group having a plurality of band-pass filters each passing a transmission wave of an odd-number (or even-number) channel between the even-number (or odd-number) minimum and maximum numbers, The constant impedance band-pass filter of the first filter group, wherein the outputs of the third and fourth terminals have a phase difference of 90 ° with each other and have substantially the same electrical characteristics. And a third hybrid circuit of the first and second hybrid circuits.
And two high-selectivity band-pass filters connected between a fourth terminal and a predetermined even-numbered (or odd-numbered) channel for transmitting transmission waves. The second terminal and the first terminal of the first hybrid circuit of the adjacent constant-impedance band-pass filter are connected to each other in cascade, and the plurality of cascaded constant-impedance band-pass filters are connected to each other. The first terminal of the constant impedance band-pass filter at both ends where the first terminal of the first hybrid circuit is not connected to the second terminal of the first hybrid circuit of the adjacent constant impedance band-pass filter.
A first terminal of the hybrid circuit is connected to the second filter group, and a second terminal of the first hybrid circuit adjacent to both ends of the cascade-connected plurality of constant impedance band-pass filters. The second terminal of the first hybrid circuit in the constant impedance band-pass filter not connected to the first terminal of the first hybrid circuit of the impedance band-pass filter is connected to the antenna, and the second filter group has a pass band. On the edge of
Concave amplitude characteristics with greater attenuation at the center of the passband
Having a predetermined odd number (or even number), respectively.
Low selectivity connected in parallel to pass the transmission wave of the channel
It is composed of a plurality of band-pass filter shape and wherein the Rukoto. Further, according to the present invention, the second filter group includes a plurality of constant impedance band-pass filters each passing a transmission wave of an odd number (or even number) channel, and each of the constant impedance band pass filters includes: A third and fourth hybrid circuit having outputs of the third and fourth terminals having a phase difference of 90 ° from each other and having electric characteristics having substantially equal amplitudes, and a third hybrid circuit of the third and fourth hybrid circuits; Connected between the third and fourth terminals , has a concave amplitude characteristic, and has a predetermined odd number.
Pass the transmission wave of the (or even numbered) channel 2
Is composed of a number of low selectivity Bandpass filters, pre-Symbol the constant impedance bandpass filter, a second terminal of the third hybrid circuit of the adjacent constant impedance bandpass filter and the first terminal A third hybrid circuit of a constant impedance bandpass filter connected to each other and cascaded, and having first terminals of a third hybrid circuit adjacent to both ends of the plurality of cascaded constant impedance bandpass filters. The first terminal of the third hybrid circuit in the constant impedance band-pass filter not connected to the second terminal of the third hybrid circuit is connected to an anti-reflection terminator, and both ends of the cascade-connected plurality of constant impedance band-pass filters, The third terminal of the constant impedance bandpass filter adjacent to the second terminal of the third hybrid circuit. A second terminal of the third hybrid circuit is characterized in that it is connected to the first filter group of the first constant impedance bandpass filter which is not connected to the terminals of the hybrid circuit.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. FIG. 1 is a block diagram illustrating a schematic configuration of an antenna duplexer according to an embodiment of the present invention. The antenna duplexer of the present embodiment
This is an embodiment in the case where the used channel arrangement is as shown in FIG. As shown in the figure, the antenna duplexer according to the present embodiment has a first filter group (FG1) and a second filter group (FG2). In the first filter group (FG1) shown in FIG. 1, the first hybrid circuit (H14
a), the second hybrid circuit (H14b), and the band-pass filters (B14a, B14b) are a constant-impedance band-pass filter that allows transmission waves of 14 channels to pass therethrough, the first hybrid circuit (H16a), The hybrid circuit (H16b) and the band-pass filters (B16a, B16b) include a constant-impedance band-pass filter for transmitting transmission waves of 16 channels, a first hybrid circuit (H22a), and a second hybrid circuit (H22b). ) And the band-pass filters (B22a, B22b) form a constant-impedance band-pass filter that allows transmission waves of 22 channels to pass. The configuration of the first filter group (FG1) is such that the transmission wave input from the first terminal (Ta) of the second hybrid circuit (H14b, H16b, H22b) is a transmission wave of every other channel. In some respects, it differs from the configuration of the configuration line sharing device shown in FIG. Each hybrid circuit is
If the output of the third terminal (Tc) and the output of the fourth terminal (Td) have a phase difference of 90 ° from each other, and the hybrid circuit is configured such that the amplitudes are substantially equal,
Any hybrid circuit can be used.

Hereinafter, the operation of the first filter group (FG1) of the present embodiment will be described by taking transmission waves of 14 channels as an example. The 14-channel transmission waves input from the first terminal (Ta) of the second hybrid circuit (H14b) are split into two transmission waves having phases different from each other by 90 ° in the second hybrid circuit (H14b). , Second
Terminal (Tc) of the hybrid circuit (H14b)
And the fourth (Td). The transmission waves branched into the two are respectively passed through a band-pass filter (B14).
a, B14b) through the first hybrid circuit (H
14a) are input to the third terminal (Tc) and the fourth terminal (Td), are combined in the first hybrid circuit (H14a), and are combined from the second terminal (Tb) of the first hybrid circuit (H14a). Is output. Next, the transmission waves of the 14 channels output from the second terminal (Tb) of the first hybrid circuit (H14a) are input to the first hybrid circuit (H16a) via the first terminal (Ta). And the first
In the hybrid circuit (H16a), the signal is branched into two transmission waves having phases different from each other by 90 °, and output from the third terminal (Tc) and the fourth terminal (Td). However, since the transmission waves of the 14 channels cannot pass through the band-pass filters (B16a, B16b), they are totally reflected by the band-pass filters (B16a, B16b), and the third terminal (H16a) of the first hybrid circuit (H16a). T
c) and input to the fourth terminal (Td), are combined by the first hybrid circuit (H16a), and are output from the second terminal (Tb) of the first hybrid circuit (H16a). Hereinafter, in the same manner, the antenna (ANT) is reached,
Radiated from an antenna (ANT).

FIG. 2 shows a second filter group (F) shown in FIG.
It is a block diagram which shows schematic structure of an example of G2). The second filter group (FG2) shown in the figure receives the transmission waves of channels 15, 17, 19, and 21 output from the respective transmitters and passes the transmission waves of channels 15, 17, 19, and 21 respectively. Filters (B15, B17, B19,
B21) are connected in parallel. Hereinafter, before describing the functions and effects of the antenna duplexer of the present embodiment, problems of the antenna duplexer shown in FIG. 20 will be described. FIG. 21 shows each band-pass filter (B14a, B14b, B15a, B15b, B16) used in FIG.
(a, B16b) is a schematic diagram showing transmission characteristics (or attenuation characteristics) and reflection characteristics. In general, a bandpass filter having a steep attenuation characteristic does not actually exist. Therefore, two bandpass filters that pass a transmission wave of an adjacent channel have transmission characteristics and reflection characteristics that are excessive in the attenuation region. It has a wrapping portion (overlapping portion). For example, the transmission characteristics of the band-pass filters (B14a, B14b) passing the transmission waves of 14 channels indicated by the solid lines in FIG. 21 and the band-pass filters (B15a, B15b) passing the transmission waves of 15 channels indicated by the broken lines in FIG. ) Overlap in the attenuation region.

Also in the antenna duplexer shown in FIG. 20, the transmission waves of the 14 channels output from the second terminal (Tb) of the first hybrid circuit (H14a) pass through the first terminal (Ta). Via the first hybrid circuit (H
15a) to the first hybrid circuit (H15
In a), the signal is branched into two transmission waves having phases different from each other by 90 °, and the third terminal (Tc) and the fourth terminal (Td)
Output from However, the bandpass filter (B
14a and B14b) and the reflection characteristics of the band-pass filters (B15a and B15b) have an overlapped portion in the attenuation range, and therefore, the third terminal (Tc).
And the 14-channel transmission waves output from the fourth (Td) are not totally reflected by the band-pass filters (B15a, B15b), and a part of them is
a, B15b). For this reason, as shown by the dashed line in FIG.
As for the transmission wave of the channel, the insertion loss increases, the attenuation at the edge of the pass band increases, and the amplitude deviation in the pass band increases. The transmission wave passing through the band-pass filters (B15a, B15b) among the transmission waves of the 14 channels is sent to the third terminal (Tc) and the fourth terminal (Td) of the second hybrid circuit (H15b). The signals are input, synthesized by the second hybrid circuit (H15b), and output from the second terminal (Tb) of the second hybrid circuit (H15b) to the reflectionless terminator (R).

FIGS. 3 to 8 show the bandpass filters (B14a, B14a, B1a) of the first filter group (FG1) of this embodiment.
B14b, B16a, B16b, B22a, B22b)
5 is a graph showing frequency characteristics of an example of a high-selectivity band-pass filter that compensates for an amplitude deviation and a group delay time, which is used for (1). FIGS. 3 to 8 show band pass filters (B14a, B14b, B16a, B16b, B22).
FIGS. 7A and 7B are graphs showing frequency characteristics when a circular waveguide resonator type high-selectivity band-pass filter that compensates for amplitude deviation and group delay time is used. FIG. 3 is a graph showing transmission characteristics, and the horizontal axis represents frequency (MH).
z), the memory interval is 2 MHz, and the vertical axis is the attenuation (dB)
And the memory interval is 5 dB. FIG. 4 is a graph showing the graph shown in FIG. 3 in an enlarged manner. The memory interval on the horizontal axis is 2 MHz, and the memory interval on the vertical axis is 1 dB. FIG.
5 is a graph showing the graph shown in FIG.
The memory interval on the horizontal axis is 1 MHz, and the memory interval on the vertical axis is 0.
2 dB. FIG. 6 is a graph showing the group delay time characteristic, in which the horizontal axis represents the frequency (MHz) and the memory interval is 1 MHz.
z, vertical axis is group delay time (τ), memory interval is 100n
s. FIG. 7 is a graph showing the reflection characteristics. The horizontal axis represents the frequency (MHz), the memory interval is 2 MHz, the vertical axis is the attenuation (dB), and the memory interval is 5 dB. FIG.
8 is a graph showing the graph shown in FIG. 7 in an enlarged manner, wherein the memory interval on the horizontal axis is 2 MHz and the memory interval on the vertical axis is 1 dB. Thus, in the antenna duplexer of the present embodiment, each band-pass filter (B14a, B14b, B16a, B16b, B22) in the first filter group (FG1).
a, B22b) as shown in FIGS.
A high-selectivity band-pass filter that compensates for amplitude deviation and group delay time is used. Further, the first terminal (T) of the second hybrid circuit (H14b, H16b, H22b).
Since the transmission wave input from a) is a transmission wave of every other channel, the transmission wave of each channel is transmitted through a band-pass filter (B14a, B14b, B16a, B16b, B2).
2a, B22b) without being affected by the band-pass filters (B14a, B14b, B16a, B16b, B
22a, B22b) are totally reflected by the antenna (ANT)
Supplied to

Further, in the first filter group (FG1), the second hybrid circuits (H14b, H16b,
The transmission wave of each channel input from each first terminal (Ta) of H22b) is transmitted to the first hybrid circuit (H14
a, H14a, H14a) are not output to the first terminal (Ta), so that the transmission wave of each channel of the first filter group (FG1) is affected by the effect of the second filter group (FG2). I will not receive it.

As described above, in the antenna duplexer according to the present embodiment, the antenna (AN) is connected to the first filter group (FG1).
T), it is possible to reduce the insertion loss of each transmission wave supplied to the antenna (AN) from the first filter group (FG1).
Since each transmission wave supplied to T) is a transmission wave that has passed through a high-selectivity band-pass filter that compensates for the amplitude deviation and the group delay time, the in-band amplitude deviation can be reduced. 9 to 12 are graphs showing frequency characteristics of an example of the first filter group (FG1) of the present embodiment. FIGS. 9 to 12 show a high-selectivity band-pass filter (B14a, B14a,
B14b, B16a, B16b, B22a, B22b)
7 is a graph showing frequency characteristics of a first filter group (FG1) when a circular waveguide resonator type band-pass filter is used. FIG. 9 is a graph showing the transmission characteristics. The horizontal axis represents the frequency (MHz), and the memory interval is 2 MH.
z, the vertical axis is the attenuation (dB), and the memory interval is 5 dB. FIG. 10 is a graph showing the graph shown in FIG. 9 in an enlarged manner, wherein the memory interval on the horizontal axis is 2 MHz and the memory interval on the vertical axis is 1 dB. FIG. 11 is a graph showing the reflection characteristics. The horizontal axis represents the frequency (MHz), and the memory interval is 2 MHz.
z, the vertical axis is the attenuation (dB), and the memory interval is 5 dB. FIG. 12 is an enlarged graph of the graph shown in FIG. 11, in which the memory interval on the horizontal axis is 2 MHz and the memory interval on the vertical axis is 1 dB.

In the antenna duplexer of the present embodiment, the transmission waves of each channel, for example, the transmission waves of 15 channels, output from the second filter group (FG2),
Through the first hybrid circuit (H1)
4a) to the first hybrid circuit (H14
In a), the signal is branched into two transmission waves having phases different from each other by 90 °, and the third terminal (Tc) and the fourth terminal (Td)
Output from For the above-described reason, the transmission waves of the 15 channels are transmitted to the bandpass filters (B14a, B1).
4b), a part thereof passes through the band-pass filters (B14a, B14b) without being totally reflected. The band-pass filters (B14a, B1a) in the transmission waves of the 15 channels are used.
4b) is input to the third terminal (Tc) and the fourth terminal (Td) of the second hybrid circuit (H14b), and is transmitted to the second hybrid circuit (H14).
b) the second hybrid circuit (H14b)
Is output from the second terminal (Tb) of the second hybrid circuit (H14a) to the non-reflection terminator (R).
Does not affect the transmitter connected to the terminal (Ta). Similarly, the transmission waves of the 15 channels are not totally reflected by the band-pass filters (B16a, B16b), and some of them pass through the band-pass filters (B16a, B16b). However, each band-pass filter (B15, B17, B19, B2) in the second filter group (FG2)
1) is a bandpass filter of a low selectivity type as shown in FIG. 13, and as a characteristic thereof, a characteristic in which the amplitude deviation in the passband is almost flat can be obtained. FIG. 13 is a graph showing transmission characteristics of an example of a low-selectivity band-pass filter used in the second filter group (FG2) of the present embodiment.

Therefore, the transmission waves of the 15 channels are not totally reflected by the band-pass filters (B14a, B14b) and the band-pass filters (B16a, B16b), and a part of them is not reflected by the band-pass filters (B14a, B14b). Even if the signal passes through the band-pass filters (B16a, B16b), the in-band amplitude deviation in the pass band can be reduced. Therefore, as shown in FIG. 14, it is possible to reduce the insertion loss of the transmission waves of the 15 channels supplied to the antenna (ANT) and reduce the in-band amplitude deviation. Each band-pass filter (B15, B17, B19, B2) in the second filter group (FG2)
1) is a low-selectivity type band-pass filter, and cannot remove an IM wave near a transmission wave. However, this IM wave is applied to each band-pass filter (B14a, B14a, B14a, B14a, B14) in the first filter group (FG1). B14b, B16a, B16b, B2
2a, B22b) and is absorbed by the non-reflection terminator (R). As described above, in the antenna duplexer of the present embodiment, it is possible to reduce the insertion loss of each channel transmission wave supplied to the antenna (ANT) and to reduce the in-band amplitude deviation. For example, in the case of digital television broadcasting, an amplitude deviation within a pass band of, for example, 0.5 dB or less is obtained due to restrictions on bit error rate characteristics. However, in the antenna duplexer of the present embodiment, The amplitude deviation in the pass band within 0.5 dB can be easily realized. For example, when the amount of transmission waves passing through the band-pass filters (B14a, B14b) in the transmission waves of 15 channels is large, the first filter group (F
G1) and is supplied to the antenna (ANT) 15
The amplitude deviation in the band of the transmission wave of the channel becomes large,
In that case, each band pass filter (B15, B17,
B19, B21), use of a low-selectivity band-pass filter having a concave amplitude characteristic in which the attenuation at the center of the pass band is larger than that at the edge of the pass band as shown in FIG. Accordingly, it is possible to reduce the in-band amplitude deviation of each channel transmission wave supplied to the antenna (ANT).

FIG. 16 is a block diagram showing a schematic configuration of another example of the second filter group (FG2) shown in FIG. In the figure, H15a, H17a, H19a, H
21a is a first hybrid circuit, H15b, H17
b, H19b and H21b are the second hybrid circuit, B
15a, B15b, B17a, B17b, B19a, B
19b, B21a and B21b are bandpass filters. Each hybrid circuit is arbitrary as long as the output of the third terminal (Tc) and the output of the fourth terminal (Td) have a phase difference of 90 ° from each other and are configured to have substantially the same amplitude. Can be used. The second filter group (FG) shown in FIG.
2), like the first filter group (FG1) shown in FIG. 1, is configured by cascading constant impedance bandpass filters. The second filter group (FG) shown in FIG.
2) Each band pass filter (B15a, B15b, B1)
7a, B17b, B19a, B19b, B21a, B2
1b) is a low-selectivity band-pass filter having a flat amplitude characteristic or a concave amplitude characteristic. Even if the second filter group (FG2) shown in FIG. 6 is used, the same operation and effect as described above can be obtained. As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist of the invention. Of course, it is.

[0018]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. ADVANTAGE OF THE INVENTION According to this invention, in the antenna duplexer which supplies the transmission wave of an adjacent channel to an antenna, it becomes possible to reduce the insertion loss of each transmission wave, and to reduce the in-band amplitude deviation of each transmission wave.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an antenna duplexer according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of an example of a second filter group illustrated in FIG. 1;

FIG. 3 is a graph showing transmission characteristics of an example of a high-selectivity band-pass filter that can be used for a first filter group according to an embodiment of the present invention and compensates for amplitude deviation and group delay time.

FIG. 4 is a graph showing an enlargement of the graph shown in FIG. 3;

FIG. 5 is a graph showing the graph shown in FIG. 4 in a further enlarged manner.

FIG. 6 is a graph showing group delay time characteristics of an example of a high-selectivity band-pass filter that can be used for the first filter group according to the embodiment of the present invention and compensates for amplitude deviation and group delay time. .

FIG. 7 is a graph showing a reflection characteristic of an example of a high-selectivity band-pass filter that can be used for the first filter group according to the embodiment of the present invention and compensates for amplitude deviation and group delay time.

FIG. 8 is an enlarged graph showing the graph shown in FIG. 7;

FIG. 9 is a graph showing transmission characteristics of an example of a first filter group according to the embodiment of the present invention.

FIG. 10 is an enlarged graph showing the graph shown in FIG. 9;

FIG. 11 is a graph showing a reflection characteristic of an example of the first filter group according to the embodiment of the present invention.

FIG. 12 is an enlarged graph showing the graph shown in FIG. 11;

FIG. 13 is a graph showing transmission characteristics of an example of a low-selectivity band-pass filter usable for the second filter group according to the embodiment of the present invention.

FIG. 14 is a schematic diagram for explaining frequency characteristics of the antenna duplexer according to the embodiment of the present invention.

FIG. 15 is a graph showing transmission characteristics of another example of a low-selectivity band-pass filter usable for the second filter group according to the embodiment of the present invention.

FIG. 16 is a block diagram showing a schematic configuration of another example of the second filter group shown in FIG. 1;

FIG. 17 is a diagram illustrating an example of a channel arrangement used in a conventional analog television broadcast.

FIG. 18 shows a case where channels used are arranged as shown in FIG.
It is a block diagram which shows the schematic structure of the conventional antenna sharing apparatus.

FIG. 19 is a diagram illustrating an example of a used channel arrangement in television broadcasting using adjacent channels.

FIG. 20 shows a case where the channels used are arranged as shown in FIG.
1 is a block diagram showing a schematic configuration of an antenna duplexer devised by the present inventors before the present application.

21 is a schematic diagram showing transmission characteristics (or attenuation characteristics) and reflection characteristics of each band pass filter used in FIG.

[Explanation of symbols]

ANT: antenna, R: non-reflection terminator, FG1: first filter group, FG2: second filter group, H13a, H13
13b, H14a, H14b, H15a, H15b, H
16a, H16b, H17a, H17b, H19a, H
19b, H21a, H21b, H22a, H22b, H
23a, H23b: Hybrid circuit, Ta, Tb, T
c, Td terminal, B13a, B13b, B14a, B1
4b, B15, B15a, B15b, B16a, B16
b, B17, B17a, B17b, B19, B19a,
B19b, B21, B21a, B21b, B22a, B
22b, B23a, B23b ... band-pass filters.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 1/04 H01P 1/213 H01Q 5/00 H04J 1/12

Claims (2)

(57) [Claims] A first filter group having a plurality of constant-impedance band-pass filters for passing transmission waves of even-numbered (or odd-numbered) channels; cascade-connected to the first filter group; A second group of filters having a plurality of band-pass filters that pass transmission waves of odd-numbered (or even-numbered) channels between even-numbered (or odd-numbered) minimum and maximum numbers. A shared device, wherein each of the constant impedance bandpass filters of the first filter group has an output of a third and a fourth terminal at 90 ° with respect to each other.
And a first and second hybrid circuit having electrical characteristics having substantially the same amplitude as each other, and a predetermined circuit connected between third and fourth terminals of the first and second hybrid circuits. And two high-selectivity band-pass filters for transmitting transmission waves of even-numbered (or odd-numbered) channels. Each of the constant-impedance band-pass filters is composed of an adjacent constant-impedance band-pass filter. A second terminal and a first terminal of the first hybrid circuit are connected to each other and cascaded, and a first terminal at both ends of the plurality of cascaded constant impedance band-pass filters.
The first terminal of the first hybrid circuit in the constant impedance bandpass filter in which the first terminal of the hybrid circuit is not connected to the second terminal of the first hybrid circuit of the adjacent constant impedance bandpass filter is the second terminal of the second circuit. , A second terminal of the first hybrid circuit adjacent to the second terminal of the first hybrid circuit at both ends of the plurality of cascade-connected constant impedance bandpass filters. a second terminal of the first hybrid circuit is connected to the antenna in not connected to the first terminal constant impedance bandpass filter, the second filter group is compared with the edge portion of the passband
Has a concave amplitude characteristic with large attenuation at the center of the passband.
And a predetermined odd-numbered (or even-numbered) channel
Low selectivity type connected in parallel
Antenna sharing apparatus according to claim Rukoto is composed of a plurality of bandpass filters. 2. The method according to claim 1, wherein each of the second filter groups is an odd number.
Pass the transmission wave of the numbered (or even numbered) channel
A plurality of constant impedance band-pass filters, wherein each of the constant impedance band-pass filters
And the outputs of the fourth terminal have a phase difference of 90 ° from each other.
Both the third and the third have electric characteristics having substantially the same amplitude.
And a fourth hybrid circuit, and third and fourth hybrid circuits of the third and fourth hybrid circuits.
4 and connected to the edge of the pass band.
Concave amplitude with greater attenuation at the center of the passband than the minute
Have a characteristic and a predetermined odd-numbered (or even-numbered) channel
Two low-selectivity bandpasses to pass the tunneling transmission wave
And each of the constant impedance bandpass filters is adjacent to each other.
Third hybrid of constant impedance bandpass filter
The second terminal and the first terminal of the circuit are connected to each other.
Cascaded, and the plurality of cascaded
Third high at both ends of the impedance bandpass filter
Constant impedance where the first terminal of the bridging circuit is adjacent
Second end of third hybrid circuit of bandpass filter
For constant impedance bandpass filters not connected to
The first terminal of the third hybrid circuit is a non-reflective
A plurality of cascaded constant impedance band-pass filters connected to
The second of the third hybrid circuit at both ends of the filter.
The terminal of the constant impedance bandpass filter
3 that is not connected to the first terminal of the hybrid circuit.
Third Hybrid in Impedance Bandpass Filter
A second terminal of the scanning circuit is connected to the first filter group.
Re antenna sharing apparatus according to claim 1, characterized in Rukoto.