JP4385661B2 - TV multidirectional receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a television multi-directional receiving apparatus that is used to receive terrestrial broadcast television radio waves coming from multiple directions, in which analog television and digital television are mixed, and includes an antenna, a booster, and a mixer.
[0002]
[Prior art]
As a conventional television multi-directional receiving apparatus, there is one in which television reception signals from antennas having different directions are mixed by a mixer composed of LPF and HPF (see, for example, Non-Patent Document 1).
[0003]
FIG. 7 shows a conventional receiving apparatus described in Non-Patent Document 1. Conventionally, when receiving a plurality of television radio waves having different radio wave arrival directions, a mixer that passes a plurality of antennas and a frequency suitable for each channel is used.
[0004]
In FIG. 7, filter mixing including a combination of LPF and HPF that passes signals received by an antenna 11 directed to a broadcasting station in the A region and an antenna 12 directed to a broadcasting station in the B region and the C region. Input to the receiver 103 and the reception signal is connected to the television receiver. Note that the LPF and HPF not only allow signals to pass through, but also have a role of attenuating ghost waves coming from outside the direction to be received by the attenuation band characteristics of the LPF characteristics and HPF characteristics shown in FIG.
[0005]
[Non-Patent Document 1]
Television reception know-how collection, terrestrial broadcasting edition, January 1995, compilation and publication, Television reception improvement committee, secretariat, Japan Broadcasting Corporation sales office (pages 22-23, Fig. 2-12)
[0006]
[Problems to be solved by the invention]
However, in the conventional configuration, terrestrial digital broadcasting has been started all over Japan, and there is a problem that it is difficult to receive in an area where channel allocation is not separable between LPF and HPF.
[0007]
For example, in FIG. 7, not only UHF13-18ch where the digital broadcast channel passes LPF from the A area broadcasting station to the conventional analog station but also 24ch is broadcast, and the 23ch and 25ch which are between LPF and HPF than B and C area broadcasting stations. , 26ch is broadcast, the digital broadcast channel 23-26ch is not a pass band of the filter mixer 13 and is attenuated, and normal reception cannot be performed. Conventionally, in the case of a channel arrangement that cannot be separated by a filter, signal synthesis is performed using a mixer that does not have filter characteristics. However, it is not preferable that the passing loss of the mixer increases and that a ghost wave is received.
[0008]
FIG. 8 is also a conventional reception example, but is a television multi-directional receiving apparatus in which the reception point is far from the B and C regional broadcasting stations and the TV broadcast radio wave is amplified by the booster 14. In this case as well, it is difficult to receive 23ch, 24ch, 25ch, and 26ch that are not the passband of the filter mixer 13 as in FIG. When the filter mixer 13 is replaced with a mixer that can pass through all channels, not only the received radio wave attenuates, but also the ghost wave in the frequency band not received by the booster and the thermal noise component amplified by the booster. It was added, and the reception on the side without the booster was hindered. Furthermore, if the degree of coupling between the terminals of the mixer is small unless the distance between the antenna 11 and the antenna 12 is set, the booster gain exceeds the sum of the loss between the mixer terminals and the coupling loss between the antennas, and the booster oscillates. Could not be received.
[0009]
The present invention solves the above-described conventional problems, and provides a television multi-directional receiver capable of supplying television radio waves to a television receiver by coexisting conventional analog television broadcasting and digital broadcast waves newly arranged in channels. Objective.
[0010]
[Means for Solving the Problems]
In order to solve the above-described conventional problems, a television multi-directional receiving apparatus according to the present invention receives a first antenna directed to a first television broadcast station and a reception radio wave of the first television broadcast station. A second antenna directed to a second television broadcast station with weak radio waves, an LPF that passes a frequency equal to or lower than the upper limit frequency Y of the channel of the first television broadcast station for the output of the first antenna; As for the output of the booster, the HPF which passes the frequency lower than the frequency Y of the second television broadcasting channel and the frequency X which is lower than the frequency Y is mixed with the output of the LPF and the HPF and the transmission loss is reduced. When the antenna coupling loss between the mixer of γ (dB), the first antenna and the second antenna is α (dB), and the inter-terminal coupling loss of the mixer is β (dB), the first Booster and is amplified by the gain of the output of the antenna [delta] (dB) is α + β (dB) or less was by gamma (dB) or more
Have.
[0011]
With this configuration, all broadcast channels can coexist and supply TV radio waves to the TV receiver without causing ghost interference that occurs when receiving analog TV broadcasts and digital broadcast waves that are newly placed in the unlog TV. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings.
[0013]
FIG. 1 is a configuration diagram of a television multidirectional receiving apparatus according to Embodiment 1 of the present invention. In FIG. 1, the same reference numerals are used for the same components as those in FIGS. 7 and 8.
[0014]
The antenna 11 receives the analog n channel and the digital X channel toward the A area broadcasting station, while the antenna 12 receives the analog m channel and the digital Y channel of the B area broadcasting station.
[0015]
Here, when the relationship of n <m holds for the analog channel that has been received conventionally, the upper limit of the LPF is set to a frequency corresponding to the n channel, and the lower limit frequency of the HPF is set to the m channel frequency. As shown in FIG. 7, a satisfactory received radio wave could be sent to the television receiver. In the future, digital broadcasting channels will be allocated nationwide, and the digital X channel of the A regional broadcasting station will have a higher frequency than the analog n channel, and the digital Y channel will have a lower frequency than the analog m channel of the B regional broadcasting station. appear.
[0016]
In order to cope with such a case, the all-band pass mixer 17 is passed through the LPF 19 with the upper limit frequency of the X channel and the HPF 20 with the lower limit frequency of the Y channel and the mixer 21 to pass through all the broadcast channels. Can be received.
[0017]
FIG. 2 (a) is a diagram for explaining the operation of the television multi-directional receiver according to Embodiment 1 of the present invention. FIG. 2 (b) shows the characteristics of the all-band pass mixer 17. FIG. Passing loss occurs about 4 dB. In order to prevent the deterioration of the TV radio wave due to this loss, a booster 18 consisting of suppressing the gain at a frequency corresponding to at least the Y channel and the X channel is connected to the output of the antenna 12 on the weak radio wave side to amplify the received radio wave. ing. The condition that the booster 18 does not oscillate abnormally is that the sum of the antenna coupling loss between the two antenna output terminals shown in FIG. 2 and the inter-terminal coupling loss between the inputs of the all-band pass mixer 17 exceeds the amplification gain of the booster 18. It is.
[0018]
FIG. 3 is a diagram showing a circuit configuration of the all-band pass mixer 17 according to the first embodiment of the present invention. The all-band mixer 17 includes an inductor, a capacitor, and a transformer. The LPF 19 uses a two-stage trap to remove unnecessary high-frequency analog channel signals from the LPF 19 and the HPF 20 uses a two-stage trap to remove unnecessary low-frequency analog channel signals. The mixer 21 is composed of a transformer-type distributor and an impedance matching device, and has a flat frequency characteristic and a passing loss characteristic of about 4 dB. The choke coil 35 is a power supply circuit for the booster 18. The antenna coupling loss increases as the antenna distance increases, but decreases to about 10 dB when installed in the vicinity of several tens of centimeters. Further, the coupling loss between the terminals of the all-band mixer 17 having the attenuation frequency can be about 20 dB from the attenuation characteristics of the LPF 19 and the HPF 20, and the coupling loss between the terminals of the mixer 21 is added to obtain a sufficient attenuation. . On the other hand, the inter-terminal coupling loss between the Y channel and the X channel, which is a common pass band of the LPF 19 and the HPF 20, is substantially the same as the inter-terminal coupling loss of the mixer 21. The coupling loss between the terminals of the mixer 21 varies greatly due to impedance mismatch of the next connected device, and it is necessary to consider a worst case of about 10 dB. That is, the sum of the antenna coupling loss and the inter-terminal coupling loss of the all-band mixer 17 is about 20 dB at worst, and the gain between the Y channel and the X channel of the UHF booster 18 needs to be suppressed to 20 dB or less. A household booster that is widely used for analog television has a standard gain of about 30 dB, and requires a characteristic in which at least a specific band is attenuated as shown in FIG. FIG. 4 is a diagram showing the amplification gain characteristic of the booster according to the first embodiment of the present invention.
[0019]
FIG. 5 is a circuit configuration block diagram of the UHF booster 18 for realizing the characteristics of FIG. The first stage amplifier 22, the 2nd amplifier 23, and the final stage amplifier 24 are normal transistor amplifiers each composed of one amplifying element. The attenuation switch 31 is used when the signal is sufficiently large, and an interstage level adjuster 34 that does not deteriorate noise performance is used for normal level adjustment. The band trap filter 33 for attenuating the specific band frequency by about 10 dB is an attenuation trap circuit that limits the amount of attenuation by a resistor in a series resonance circuit composed of an inductor and a capacitor. If inserted between the 2nd amplifier 23 and the final amplifier 24, the noise figure of the amplifier is deteriorated if it is inserted in the previous stage, and the reception of the weak electric field is hindered. If it is between the final amplifier 24 and the output terminal, This is because booster saturation is likely to occur when the radio wave of a nearby broadcasting station is large, and consideration is given to the strong electric field and the weak electric field of the radio wave. The gain equalizer 32 is usually inserted between the amplifier stages in order to attenuate the low frequency in order to flatten the gain frequency characteristic of the amplifying element.
[0020]
The digital broadcast channel Y passing through the booster 18 attenuated in a specific band is sent to the television receiver about 10 dB lower than the analog channel. However, in the digital broadcast wave sent in the Japanese broadcasting standard, Even when the input signal level is lower than that of the analog wave, the image quality rank is good. FIG. 6 is a diagram showing the relationship between the receiver input level and the image quality rank. The receiver input level is indicated by five image quality ranks, and 4 or higher is an index that can stand 3.
[0021]
Note that the gain characteristic of the booster may be a low amplification gain that does not have a band trap characteristic such that the booster does not oscillate in an area where the broadcast radio wave is not so weak. Further, when the reception area is far from the A area and is close to the B area, a similar amplification gain characteristic booster may be inserted on the antenna 11 side.
[0022]
When the reception radio waves from the A and B regions are about the same, the front channel can be received with the configuration of the antenna 11, the antenna 12, and the all-band pass mixer 17 without a booster, and the radio waves of both companies are weak. In this case, a booster may be connected to the output of the all-band mixer 17.
[0023]
That is, in an environment where a conventional analog television signal can be satisfactorily received, a digital television signal having a low level of about 10 dB according to the embodiment of the present invention can be received as a sufficient signal level.
[0024]
The output of the mixer 22 of the received signal passes through the booster power supply 15 and the distributor 16 and is distributed to a plurality of television receivers in each room.
[0025]
【The invention's effect】
As described above, the present invention can receive all the broadcast channels of the conventional analog TV broadcast and the digital broadcast wave newly arranged when receiving a radio wave coming from a distance and a TV wave from a different direction. A multi-directional television wave can be supplied to the television receiver without causing ghost interference and without causing booster oscillation.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a television multi-directional receiver according to Embodiment 1 of the present invention. FIG. 2 is an operation explanatory diagram of the television multi-directional receiver according to Embodiment 1 of the present invention. FIG. 4 is a diagram showing an amplification gain characteristic of the booster according to the first embodiment of the present invention. FIG. 5 is a circuit diagram of the UHF booster according to the first embodiment of the present invention. FIG. 6 is a diagram showing the relationship between the receiver input level and the image quality rank. FIG. 7 is a block diagram of a conventional television multi-directional receiver. FIG. 8 is an explanatory diagram of problems of the conventional television multi-directional receiver. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Antenna 12 Antenna 13 Filter mixer 14 Booster 15 Booster power supply 16 Divider 17 All-band pass mixer 18 UHF booster 19 LPF
20 HPF
21 Mixer 22 First-stage amplifier 23 2nd amplifier 24 Last-stage amplifier 31 Attenuation switch 32 Gain equalizer 33 Band trap filter 34 Level adjuster 35 Choke coil

Claims (4)

A first antenna for the first television broadcast station;
A second antenna directed to a second television broadcast station whose reception radio wave is weaker than the reception radio wave of the first television broadcast station;
An LPF that passes a frequency equal to or lower than an upper limit frequency Y of the channel of the first television broadcasting station for the output of the first antenna ;
An HPF that passes a frequency that is a lower limit frequency of the channel of the second television broadcasting station and that is a frequency X that is lower than the frequency Y, with respect to the output of the booster described later,
A mixer that mixes the outputs of the LPF and HPF and has a passage loss of γ (dB);
When the antenna coupling loss between the first antenna and the second antenna is α (dB) and the inter-terminal coupling loss of the mixer is β (dB), the output of the second antenna is amplified and gained. a booster in which δ (dB) is α + β (dB) or less and γ (dB) or more;
A multi-directional television receiver. A second antenna for a second television broadcast station;
A first antenna directed to the first television broadcast station whose received radio wave is weaker than the received radio wave of the second television broadcast station;
An HPF that passes a frequency equal to or higher than a lower limit frequency X of the channel of the second television broadcasting station with respect to the output of the second antenna;
An LPF that passes a frequency that is an upper limit frequency of the channel of the first television broadcasting station and is lower than a frequency Y higher than the frequency X with respect to an output of a booster described later;
A mixer that mixes the outputs of the LPF and HPF and has a passage loss of γ (dB);
When the antenna coupling loss between the first antenna and the second antenna is α (dB) and the inter-terminal coupling loss of the mixer is β (dB), the output of the first antenna is amplified and gained. a booster in which δ (dB) is α + β (dB) or less and γ (dB) or more;
A multi-directional television receiver. In the frequency band between the frequency X and the frequency Y, the booster has an amplification gain δ (dB) of α + β (dB) or less and γ (dB) or more, and other frequency bands. The television multi-directional receiver according to claim 1 or 2, wherein the case is a standard gain ε (dB) . 4. The television multi-directional receiver according to claim 3 , wherein the booster is a three-stage transistor amplifier, and a band trap filter is inserted in an intermediate stage of the transistor amplifier .

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