JP4827806B2 - Non-stop type antenna switching device - Google Patents

Description

  The present invention instantaneously transmits radio waves between a regular antenna (ordinary transmission antenna) that is always used in a radio transmission station of a broadcasting station and an emergency antenna (emergency transmission antenna) that is used in an emergency or the like. The present invention relates to a non-stop type antenna switching device for switching without notice.

  Conventionally, in a radio station of a broadcasting station, for example, as shown in FIG. 11 and FIG. 12, for example, a transmission antenna is generally divided into two systems, a normal antenna and an emergency antenna. This is a contrivance to eliminate as much as possible the case where radio waves are not emitted from the transmitting antenna even when a part of the transmitting antenna fails. The prior art shown in FIG. 11 mechanically switches between a transmission route for feeding radio waves from the broadcasting device 100 to the common antenna 101 and a transmission route for feeding radio waves from the broadcasting device 100 to the emergency antenna 102 by the switch 103. It is like that.

The prior art shown in FIG. 12 is a switching device that allows radio waves to be transmitted by any one of the antennas without interrupting the radio waves when the antennas are switched (see, for example, Patent Document 1). In this switching device, the radio wave output from the transmitter 120 is input to the hybrid power distributor 111. By this distributor 111, the absolute power value is divided into 3 dB and distributed to two waves whose phases are shifted by π / 2 (in the case of the short slot type, in the case of the magic T type, each phase is shifted by π). Distributed to waves). One wave is input to the phase shifter 113, and the phase shifter 113 can freely adjust the passing phase. The other wave is input to the hybrid power combiner 112 as it is. Here, by changing the input phase of one of the waves by the phase shifter 113, the emergency antenna 122 is fed from the state where the radio wave output from the transmitter 120 is fed to the common antenna 121 (see FIG. 12). The state can be switched (see FIG. 13). In FIGS. 12 and 13, the thickness of the arrow indicates the amount of power. This switch always has the normal antenna output + emergency antenna output = broadcaster output− (transmission loss of all systems).
JP 2001-177453 A

  By the way, in the prior art shown in FIG. 11, since the transmission route is mechanically switched by the switch 103, an instantaneous interruption always occurs at the time of switching. For this reason, for example, when the transmission route is switched from the normal antenna 101 to the emergency antenna 102, there is a considerable amount of time during which neither the normal antenna 101 nor the emergency antenna 102 emits radio waves. That is, at the time of switching, there has been a problem that an instantaneous interruption in which radio waves are not supplied to both the common antenna 101 and the emergency antenna 102 occurs.

  Further, in the switching device described in Patent Document 1, the hybrid power distributor 111 and the hybrid power combiner 112 have frequency characteristics, respectively. Therefore, when the radio waves combined in a wide band are switched, depending on the channel. There are problems such as a deviation in distribution between the common antenna 121 and the emergency antenna 122. For example, when switching the radio wave of one channel in the UHF band, there is no problem such as a deviation in the distribution between the common antenna 121 and the emergency antenna 122. However, when switching the synthesized radio wave of two or more channels, There were problems such as deviations in the distribution.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a non-disruptive switching between a normal antenna and an emergency antenna that can be switched without being interrupted. The object is to provide a wave antenna switching device.

In order to solve the above-described problem, the non-stop type antenna switching device according to the first aspect of the present invention is a non-stop type antenna that switches radio waves fed from a broadcaster between a regular antenna and an emergency antenna. a switching device, a first port, a second port and third port, while emitting radio waves incident on the first port from the broadcast unit from the second port, enters the second port a circulator for emitting radio waves from the third port, provided a radio wave emitted from the second port of the circulator to a first feed line for feeding to the common antenna, the bandwidth used for radio passband a first position, and a band-pass filter can be switched between the second position to the used bandwidth and the reflection bandwidth, switching said bandpass filter in said first position The radio wave incident on the first port of the circulator from the broadcaster and emitted from the second port is fed to the common antenna through the bandpass filter, and the bandpass filter is moved to the first port. When switched to the second position, the radio wave emitted from the second port of the circulator and reflected by the bandpass filter re-enters the second port, and the radio wave emitted from the third port of the circulator The emergency antenna is fed via a second feed line provided at the third port.

  According to this aspect, when the band-pass filter is switched to the first position, the radio wave incident on the first port of the circulator from the broadcaster and emitted from the second port is fed to the common antenna through the band-pass filter. The On the other hand, when the bandpass filter is switched to the second position, the radio wave emitted from the second port of the circulator and reflected by the bandpass filter is incident again on the second port and emitted from the third port of the circulator. Power is supplied to the antenna.

  In this way, when the bandpass filter is switched to the first position, the bandpass filter passes the use band of radio waves (for example, the UHF frequency band of 13ch to 35ch), and the radio waves in the use band are fed to the common antenna. In addition, when the bandpass filter is switched to the second position, the bandpass filter reflects the radio wave use band, and the reflected radio wave of the use band is incident again on the second port of the circulator. Power is supplied to the antenna.

  In this way, by switching the bandpass filter between the first position and the second position, radio waves in the use band supplied from the broadcaster, that is, radio waves synthesized in a wide band, can be Can be switched to and from the antenna without interruption. In addition, the radio wave fed to the service antenna is the radio wave of the use band that has passed through the bandpass filter (the radio wave combined in a wide band), and the radio wave fed to the emergency antenna is the radio wave reflected by the bandpass filter. The radio wave in the same band as the radio wave fed through the band-pass filter and fed to the common antenna. Therefore, by switching the bandpass filter between the first position and the second position, when switching the radio wave synthesized in a wide band between the service antenna and the emergency antenna, the service antenna and the emergency antenna are used. There is no problem such as deviation in distribution to the antenna.

  In a non-stop type antenna switching device according to another aspect of the present invention, radio waves in the use band emitted from the third port are transmitted to the second feeder connected to the third port. A change-over switch is provided that can be switched between a first position for feeding power to the antenna and a second position for feeding the radio wave to the dummy load.

  According to this aspect, when the radio wave emitted from the second port of the circulator is fed to the common antenna by switching the bandpass filter to the first position, the changeover switch is switched to the second position. As a result, even if a radio wave slightly leaks from the third port of the circulator during power feeding to the common antenna, the radio wave is fed to the dummy load via the changeover switch and consumed. The occurrence of problems due to leaking radio waves can be suppressed. On the other hand, when the radio wave emitted from the third port of the circulator is fed to the emergency antenna by switching the bandpass filter to the second position, the changeover switch is set to the first before the bandpass filter is switched to the second position. Switch to the position.

  In the non-stop type antenna switching device according to another aspect of the present invention, the bandpass filter includes a filter input unit connected to the second port side of the circulator via the first feeder and the common antenna. And a plurality of parallel resonance circuits formed in the housing, and each capacitor of the plurality of parallel resonance circuits. A lid to which the member is fixed, gripping a gripping part fixed to the lid, and pushing and pulling the lid against the casing between two positions, It is possible to switch between a first position where the use band of the radio wave is a pass band by changing each capacitor of the parallel resonance circuit and a second position where the use band is a reflection band.

  According to the present invention, it is possible to switch radio waves synthesized in a wide band between a normal antenna and an emergency antenna without interruption. In addition, there is no problem such as a deviation in distribution between the normal antenna and the emergency antenna. That is, it is possible to switch between the common antenna and the emergency antenna without instantaneous interruption of the same radio wave that has been combined in a wide band.

Embodiments embodying the present invention will be described with reference to the drawings. In the description of each embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.
(First embodiment)
A non-stop type antenna switching apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an outline of a configuration example in which the non-stop type antenna switching device according to the first embodiment is used in a television broadcast station. FIG. 2 is a block diagram showing a schematic configuration of the non-stop type antenna switching device, and FIG. 3 is a perspective view showing a schematic configuration of the switching device. FIG. 4 is a diagram showing a band-pass filter of the switching device, a cross-sectional view showing a state in a first position where the use band of the radio wave is a pass band, and FIG. 5 is a diagram showing the band-pass filter. It is sectional drawing which shows the state which exists in the 2nd position which uses as a reflection zone. FIG. 6 is a plan view showing the bandpass filter. FIG. 7 is a circuit diagram showing an equivalent circuit of a parallel resonant circuit constituting the bandpass filter. FIG. 8 is a diagram for explaining the operation of the bandpass filter. FIG. 9 is a graph showing the passband transition characteristics of the bandpass filter.

  As shown in FIG. 1, the non-stop type antenna switching device 1 according to the first embodiment is disposed between a common antenna 2 that is a transmission antenna in a television broadcast station and a shared device 3. The regular antenna 2 is a regular transmission antenna that is always used. Reference numeral “4” denotes an emergency antenna (temporary transmission antenna) that is used in an emergency such as when a transmission antenna related work or inspection of various devices is performed at a television broadcast station.

The shared device 3 synthesizes radio waves for a plurality of channels (channels) sent from a broadcaster 5 provided with a plurality of broadcasters 5 _{1 to} 5 _10, and eliminates radio waves in the UHF frequency band that are channel-synthesized into this wide band. Power is supplied to the stationary antenna switching device 1. In this way, the non-stop type antenna switching device 1 is fed with radio waves in the UHF frequency band that are channel-combined in a wide band from the broadcasting device 5 via the shared device 3. The non-stop type antenna switching device 1 is fed with a radio wave in the UHF frequency band that is channel-combined into a wide band corresponding to a plurality of channels in the UHF frequency band of 13ch to 35ch (channel), for example. Here, 13 ch is a broadcast wave (radio wave) with a center frequency of 473 MHz, 14 ch is a broadcast wave with a center frequency of 479 MHz,... 35 ch is a broadcast wave with a center frequency of 605 MHz. In addition, an ordinary power source 6 and an emergency power source 7 are connected to the broadcasting machine 5 of the television relay broadcasting station. Thus, a redundant system is always secured as a power supply system for the broadcaster 5.

  The non-stop type antenna switching device 1 uses the UHF frequency band radio wave that is fed from the common device 3 in a wide band without causing any instantaneous interruption (no instantaneous interruption), that is, without a continuous wave. It is possible to switch from the antenna 2 side to the emergency antenna 4 side, or from the emergency antenna 4 side to the common antenna 2 side.

A specific configuration of the non-stop type antenna switching device 1 will be described with reference to FIGS.
In FIG. 2, the code | symbol 3a is a broadcasting machine inside the shared apparatus 3 shown in FIG. A radio wave in the UHF frequency band that is channel-combined with the above-described broadband is fed from the broadcaster 3a to the non-stop type antenna switching device 1.

  As shown in FIGS. 2 and 3, the non-stop type antenna switching device 1 includes a circulator 10 and a bandpass filter (passband variable BPF) 11.

  The circulator 10 has a first port p1, a second port p2, and a third port p3. The circulator 10 emits radio waves incident on the first port p1 from the broadcaster 3a (broadcaster 5) from the second port p2, A radio wave incident on the second port p2 is emitted from the third port p3. Here, the first port p1 of the circulator 10 is fed with radio waves in the UHF frequency band that are channel-combined in a wide band.

  As shown in FIGS. 2 and 3, the bandpass filter 11 is provided on the first feed lines 12 a and 12 b that feed the radio wave emitted from the second port p <b> 2 of the circulator 10 to the common antenna 2. It is possible to switch between a first position where the band is a pass band and a second position where the used band is a reflection band. The band-pass filter 11 is connected to the second port p2 side of the circulator 10 via the first feed line 12a and to the common antenna 2 side via the first feed line 12b. And a filter output unit 11b. Here, the use band of the radio wave that the band pass filter 11 uses as the pass band or the reflection band is the UHF frequency band of 13 ch to 35 ch (the center frequency is 539 MHz and 22 × 6 MHz = 132 MHz frequency band) in this embodiment. is there.

  As shown in FIGS. 2 and 3, second feed lines 13 a and 13 b that feed radio waves emitted from the third port p 3 to the emergency antenna 4 are connected to the third port p 3 of the circulator 10. . Further, the non-stop type antenna switching device 1 includes a switch 15 having a switch 14 connected between the second feed lines 13a and 13b connected to the third port p3.

  The changeover switch 14 has a first position for feeding the radio wave emitted from the third port p3 of the circulator 10 to the emergency antenna 4 via the second feed line 13b, and a second position for feeding the radio wave to the dummy load 16. It is possible to switch between positions (positions shown in FIG. 2). As shown in FIG. 3, the switch 15 is provided with a dummy load mounting portion 15 a for mounting the dummy load 16 to the switch 15 and connecting it to the switch 14.

As shown in FIGS. 3 to 6, the band-pass filter 11 includes a housing 20 having the filter input unit 11 a and the filter output unit 11 b and a plurality of parallel resonance circuits 21 _{1 to} 21 formed in the housing 20. ₆ (see FIG. 7), and a lid body 22 to which members constituting the capacitors C _{1 to} C ₆ of the plurality of parallel resonant circuits 21 _{1 to} 21 ₆ are fixed.

A plurality (six in this example) of parallel resonant circuits 21 _{1 to} 21 ₆ are arranged between the filter input unit (input terminal) 11a and the filter output unit (output terminal) 11b. The connection points of C _{1 to} C ₆ are arranged so as to be connected to each other via the capacitors C _{11 to} C 17. The six parallel resonance circuits 21 _{1 to} 21 ₆ have different resonance frequencies f (f = 1 / 2π√LC).

The inductor L in each of the parallel resonant circuits 21 ₁ to 21 ₆ is constituted by a metallic resonance buff 23 hollow portion 23a is formed to the vicinity of the center portion. A total of six resonance buffs 23 are provided for each of the parallel resonance circuits 21 _{1 to} 21 ₆ . The base end portion of each resonance buff 23 is fixed to the lid body 22. The capacitors C _{1 to} C ₆ of the parallel resonant circuits 21 _{1 to} 21 ₆ are each provided with an adjustment screw 24 attached to the bottom wall 20 a of the housing 20 so that the amount of protrusion into the housing can be adjusted, and each adjustment screw 24. Is formed by the opposing resonance buff 23. In this example, since _six parallel resonant circuits 21 _{1 to} 21 ₆ are formed, six adjustment screws 24 are also provided. The capacitors C11 to C17 are configured by a coupling capacitance adjusting member 27 and the like disposed between the resonance buffs 23. Adjust the housing projection amount to the interior of the six adjusting screws 24, or by adjusting the position of the coupling capacitance adjusting member 27, fine adjustment of the resonance frequency f of the parallel resonant circuit 21 ₁ to 21 ₆ It is possible. As described above, each resonance buff 23 constitutes the inductor L of each parallel resonance circuit 21 _{1 to} 21 ₆ , and also constitutes each capacitor C _{1 to} C ₆ together with each adjustment screw 24.

And the band pass filter 11 hold | grips the holding part 25 fixed to the cover body 22, and pushes and pulls the cover body 22 with respect to the housing | casing 20 between the position shown in FIG. 4, and the position shown in FIG. By changing the capacitors C _{1 to} C ₆ of the parallel resonant circuits 21 _{1 to} 21 ₆ , the first position having the use band of the radio wave as the pass band and the second position having the use band as the reflection band It is possible to switch between them.

FIG. 4 shows a state in which the lid 22 is pushed into the housing 20. In this state, the parallel resonant circuit ₂₁ 1 to 21 each parallel resonant circuit ₂₁ 1 each capacitor _C 1 -C ₆ increases the _{6-21 6} of the resonance frequency f is low, as a result, the band-pass filter 11, It is switched to the first position where the use band of radio waves is the pass band. That is, the band pass filter 11 in the first position passes the use band (use channel) of radio waves as shown by the line 30 in FIG. More specifically, the band pass filter 11 at the first position is attenuated in the UHF frequency band of 13 ch to 35 ch (center frequency is 539 MHz, 22 × 6 MHz = 132 MHz frequency band) as shown by the curve 31 in FIG. The amount is 0 (dB), and all the incident radio waves in the UHF frequency band pass through the band pass filter 11.

  Therefore, in a state where the bandpass filter 11 is switched to the first position, a radio wave incident on the first port p1 of the circulator 10 from the broadcaster 3a and emitted from the second port p2 (in the UHF frequency band in which the channels are combined in a wide band). The radio wave) is fed to the common antenna 2 through the band-pass filter 11.

On the other hand, FIG. 5 shows a state in which the lid 22 is pulled with respect to the housing 20. In this state, the parallel resonant circuit ₂₁ 1 to 21 each parallel resonant circuit is smaller each capacitor _C 1 -C _{6 6 21} 1 to 21 ₆ of the resonance frequency f becomes higher, as a result, the band-pass filter 11, It is switched to the second position where the use band of radio waves is the reflection band. That is, the band pass filter 11 in the second position reflects the radio wave use band (use channel) as indicated by a line 32 in FIG. More specifically, in the band pass filter 11 at the second position, the center frequency of the pass band is shifted from 539 MHz to 839 MHz as shown by the curve 33 in FIG. As a result, the band-pass filter 11 in the second position is switched to a characteristic (reflection characteristic) of attenuation of −70 (dB) to −45 (dB) in the UHF frequency band of 13 ch to 35 ch, and the incident Almost all radio waves in the UHF frequency band are reflected by the band pass filter 11. The radio wave passing through the bandpass filter 11 is smaller than 1/10000 (−40 (dB)) of the incident radio wave.

  Therefore, in a state where the bandpass filter 11 is switched to the second position, a radio wave incident on the first port p1 of the circulator 10 from the broadcaster 3a and emitted from the second port p2 (in the UHF frequency band in which the channel is combined in a wide band). Radio wave) is reflected by the bandpass filter 11 and re-enters the second port p2. In this state, since the radio wave passing through the bandpass filter 11 is smaller than 1/10000 (−40 (dB)) of the incident radio wave, substantially all of the radio wave incident on the bandpass filter 11 from the second port p2. Is reflected by the band pass filter 11 and returns to the second port p2. The radio wave re-entering the second port p2 is emitted from the third port p3 of the circulator 10, and is supplied to the emergency antenna 4 via the changeover switch 14 that has been switched to the first position in advance.

Next, the operation of the non-stop type antenna switching device 1 having the above configuration will be described.
The emergency antenna 4 is removed when the work related to the transmission antenna and the inspection of various devices are not performed at the TV relay broadcasting station (normal time). Further, in this case, the changeover switch 14 switches the radio wave emitted from the third port p3 of the circulator 10 to the second position where the electric power is supplied to the dummy load 16, and the dummy load 16 is connected to the dummy load mounting portion of the switch 15. It is attached to 15a (shown in FIG. 3) and connected to the changeover switch 14.

  In such a normal time, the band pass filter 11 is switched to the first position (position shown in FIG. 4) having the use band of radio waves as the pass band. In the normal state where the bandpass filter 11 is switched to the first position as described above, the bandpass filter 11 has a UHF frequency band of 13ch to 35ch as a passband (center frequency is 539 MHz as shown by a curve 31 in FIG. Passband). Therefore, a radio wave that enters the first port p1 of the circulator 10 from the broadcaster 3a and exits from the second port p2 (a radio wave in the UHF frequency band that is channel-combined in a wide band) passes through the bandpass filter 11 and is a common antenna. 2 is fed.

  Even if a radio wave slightly leaks from the third port p3 of the circulator 10 during the power feeding to the service antenna 2, the radio wave is fed to the dummy load 16 through the changeover switch 14 and consumed. It is possible to suppress the occurrence of problems due to radio waves slightly leaking from the 3 port p3.

  On the other hand, the emergency antenna 4 is attached to the non-stop type antenna switching device 1 before performing the construction or inspection in an emergency such as when carrying out construction related to the transmission antenna or inspection of various devices at the TV broadcasting station. And connected to the feeder line 13b. Further, the changeover switch 14 feeds the radio wave in the use band emitted from the third port p3 of the circulator 10 to the emergency antenna 4 through the second feeder 13b.

  In this state, the grip portion 25 of the bandpass filter 11 is gripped, and the lid body 22 is pulled out from the position shown in FIG. 4 to the position shown in FIG. Thereby, the band pass filter 11 is switched from the first position having the use band of the radio wave as the pass band to the second position having the use band as the reflection band. Thus, when the bandpass filter 11 is switched to the second position, a radio wave that enters the first port p1 of the circulator 10 from the broadcaster 3a and exits from the second port p2 (in the UHF frequency band in which the channels are combined in a wide band). Radio wave) is reflected by the bandpass filter 11 and re-enters the second port p2. The radio wave that re-enters the second port p2 exits from the third port p3 of the circulator 10 and is fed to the emergency antenna 4 via the changeover switch 14.

  When the work related to the transmission antenna and the inspection work of various devices are completed at the TV broadcast station, the changeover switch 14 is switched to the second position where the radio wave emitted from the third port p3 is fed to the dummy load 16. The dummy load 16 is mounted on the dummy load mounting portion 15a of the switch 15. In this state, the bandpass filter 11 is switched from the second position to the first position again. As a result, the radio wave that enters the first port p1 of the circulator 10 from the broadcaster 3a and exits from the second port p2 (the radio wave in the UHF frequency band that is combined into a wide band) passes through the bandpass filter 11 again. Power is supplied to the common antenna 2.

  In this way, by switching the bandpass filter 11 between the first position and the second position, radio waves in the use band fed from the broadcaster 3a (broadcaster 5), that is, the channel is synthesized into a wide band. The radio wave can be switched between the service antenna 2 and the emergency antenna 4 without a momentary interruption, that is, without stopping.

According to 1st Embodiment comprised as mentioned above, there exist the following effects.
○ When the band-pass filter 11 is switched to the first position (the position shown in FIG. 4), the band-pass filter 11 passes a use band of radio waves (for example, UHF frequency band of 13ch to 35ch), and radio waves in the use band are regularly used. Power is supplied to the antenna 2. When the bandpass filter 11 is switched to the second position (position shown in FIG. 5), the bandpass filter 11 reflects the use band of the radio wave, and the reflected radio wave of the use band is sent to the second port p2 of the circulator 10. The light enters again and is supplied to the emergency antenna 4 from the third port p3 of the circulator 10 through the changeover switch 14.

  In this way, by switching the bandpass filter 11 between the first position and the second position, radio waves in the use band fed from the broadcaster 3a (broadcaster 5), that is, the channel is synthesized into a wide band. The radio wave can be switched between the service antenna 2 and the emergency antenna 4 without instantaneous interruption.

  The radio wave fed to the common antenna 2 with the bandpass filter 11 switched to the first position is a radio wave in the use band that has passed through the bandpass filter 11 (a radio wave that is combined into a wide band). Further, the radio wave fed to the emergency antenna 4 with the bandpass filter 11 switched to the second position is the radio wave reflected by the bandpass filter 11 and is normally used with the bandpass filter 11 in the first position. The radio wave is in the same band as the radio wave fed to the antenna 2. Therefore, when the band-pass filter 11 is switched between the first position and the second position, when the radio wave synthesized in a wide band is switched between the common antenna 2 and the emergency antenna 4, the common antenna is used. 2 and the distribution to the emergency antenna 4 do not cause a problem such as a deviation.

  ○ When the bandpass filter 11 is switched to the first position and the radio wave emitted from the second port p2 of the circulator 10 is fed to the common antenna 2, the changeover switch 14 is set to the second position (position shown in FIG. 2). Switch over. As a result, even if a radio wave slightly leaks from the third port p3 of the circulator 10 during power feeding to the service antenna 2, the radio wave is fed to the dummy load 16 via the changeover switch 14 and consumed. It is possible to suppress the occurrence of problems due to radio waves slightly leaking from the 3 port p3. On the other hand, when the radio wave emitted from the third port p3 of the circulator 10 is fed to the emergency antenna 4 by switching the bandpass filter 11 to the second position, before switching the bandpass filter 11 to the second position, The changeover switch 14 may be switched to the first position.

  ○ By switching the band-pass filter 11 between the first position and the second position, radio waves in the use band fed from the broadcaster 3a (broadcaster 5) are transmitted between the regular antenna 2 and the emergency antenna 4. Therefore, it is possible to efficiently carry out the construction related to the transmission antenna and the inspection work of various devices in the TV relay broadcasting station. Thereby, it is possible to shorten the work time in the construction related to the transmission antenna and the inspection work of various devices. In particular, work related to transmission antennas and inspection work for various devices are often performed at night, and night work can be performed efficiently, safely, and with little effort.

(Second Embodiment)
Next, a non-stop type antenna switching device 1A according to the second embodiment will be described with reference to FIG.
In this non-stop type antenna switching device 1A, the third port p3 of the circulator 10 is connected to the emergency antenna 4 via the feeder line 13 without passing through the changeover switch 14 as in the first embodiment. Yes. Other configurations of the non-stop type antenna switching device 1A are the same as those of the non-stop type antenna switching device 1 according to the second embodiment.

In addition, this invention can also be changed and embodied as follows.
In each of the above embodiments, the use band of the radio wave that the band-pass filter 11 uses as the pass band or the reflection band is the UHF frequency band of 13 ch to 35 ch (the center frequency is 539 MHz and 22 × 6 MHz = 132 MHz frequency band). However, the use band of radio waves is not limited to the UHF frequency band.

In each of the above embodiments, the configuration in which the bandpass filter 11 includes the _six parallel resonant circuits 21 _{1 to} 21 ₆ has been described. However, the number of resonant parallel circuits provided in the bandpass filter 11 is not limited to six.

Schematic which shows the structure which used the non-stop type | mold antenna switching device which concerns on 1st Embodiment for a television relay broadcasting station. The block diagram which shows schematic structure of the non-stop type | mold antenna switching apparatus which concerns on 1st Embodiment. The perspective view which shows schematic structure of the same switching apparatus. The figure which shows the band pass filter of the same switching apparatus, and is sectional drawing which shows the state in the 1st position which makes the use band of an electromagnetic wave pass band. The figure which shows the same band pass filter, and is sectional drawing which shows the state in the 2nd position which uses the use band of an electromagnetic wave as a reflection band. The top view which shows the same band pass filter. The circuit diagram which shows the equivalent circuit of the parallel resonant circuit which comprises the same band pass filter. Operation | movement explanatory drawing of the same band pass filter. The graph which shows the pass-band transition characteristic of the same band pass filter. The block diagram which shows schematic structure of the non-stop type | mold antenna switching apparatus which concerns on 2nd Embodiment. The block diagram which shows schematic structure of a prior art. It is a figure which shows schematic structure of another prior art, and is a block diagram which shows the state by which an electromagnetic wave is fed to the common antenna side. It is a figure which shows the same prior art as FIG. 12, and is a block diagram which shows the state in which an electromagnetic wave is fed to the emergency antenna side.

Explanation of symbols

1, 1A: Non-stop type antenna switching device 2: Common antenna 3a: Broadcaster 4: Emergency antenna 5: Broadcaster 10: Circulator p1: First port p2: Second port p3: 31st port 11: Band pass Filter 11a: Filter input unit 11b: Filter output unit 12a, 12b: First feed lines 13, 13a, 13b: Second feed line 14: Changeover switch 15: Switch 15a: Dummy load mounting unit 16: Dummy load 20 : Housings 21 _{1 to} 21 ₆ : Parallel resonant circuits C _{1 to} C ₆ : Capacitor L: Inductors C11 to C17: Capacitor 22: Lid 23: Resonant buff (member constituting the capacitor)
25: Grasping part

Claims (3)

A non-stop type antenna switching device that switches radio waves fed from a broadcaster between a service antenna and an emergency antenna,
First port, a second port and a third port, a radio wave which is incident on the first port from the broadcast unit with emitted from the second port, the radio waves third incident on the second port A circulator exiting from the port;
Provided a radio wave emitted from the second port of the circulator to a first feed line for feeding to the common antenna, to a first position in which the bandwidth used for radio passband, the used bandwidth and the reflection bandwidth A bandpass filter switchable between the second position,
When the band-pass filter is switched to the first position, radio waves that are incident on the first port of the circulator from the broadcaster and emitted from the second port pass through the band-pass filter and are used for the regular use. The antenna is powered,
When the bandpass filter is switched to the second position, the radio wave emitted from the second port of the circulator and reflected by the bandpass filter reenters the second port, and the third of the circulator A non-stop type antenna switching device, wherein a radio wave emitted from a port is fed to the emergency antenna via a second feeding line provided at the third port.   The second feeder connected to the third port has a first position for feeding the radio wave in the use band emitted from the third port to the emergency antenna, and feeds the radio wave to the dummy load. The non-stop type antenna switching device according to claim 1, further comprising a change-over switch that can be switched between the second position and the second position. The band-pass filter, the filter output which is connected via the first feed line the filter input connected via the first feed line to the second port side and the common antenna side of the circulator And a plurality of parallel resonant circuits formed in the casing, and a lid to which members constituting each capacitor of the plurality of parallel resonant circuits are fixed. By gripping a fixed gripping part and pushing and pulling the lid against the housing between two positions, the capacitors of the plurality of parallel resonance circuits are changed to reduce the use band of the radio wave. It said first position to a pass band, uninterruptible corrugated antenna switching device according to claim 1 or 2, characterized in that it is switchable between the second position to the reflection band of the used band .

Images