JP2013232840A - Retransmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retransmission device which can reduce a variable width of gain and also helps to simplify a circuit scale and cut back on costs.SOLUTION: When detection output from a detector 7 which detects output of a gain variable amplifier 4 falls below a level equivalent to provisions for low-power radio stations stipulated by a radio law, a switch 6 turns on so that output from the gain variable amplifier 4 is supplied to a retransmission antenna 10 via the switch 6. When detection output from the detector 7 exceeds a level equivalent to provisions for low-power radio stations stipulated by a radio law, the switch 6 turns off so that output from the gain variable amplifier 4 is not supplied to the retransmission antenna 10 via the switch 6. This makes it possible to reduce a variable width of gain for the gain variable amplifier 4, as well as to simplify a circuit scale and cut back on costs.

Description

  The present invention relates to a retransmission apparatus for retransmitting terrestrial digital broadcasts and multimedia broadcasts.

If the receiver terminal capable of receiving digital terrestrial broadcasting or multimedia broadcasting can be charged, if the sensitivity deteriorates due to noise generated during charging, there is a possibility that the broadcasting cannot be normally viewed during charging. In order to allow normal viewing of the broadcast even during charging, it is necessary to ensure a C / N (Carrier to Noise ratio) in a state where noise is generated.
In addition, since the re-transmission device transmits radio waves, it is necessary to satisfy the provisions of weak radio stations stipulated by the Radio Law (that is, satisfy a transmission output that does not require a radio station license).
Note that the VHF band is used for multimedia broadcasting.

  As a charging stand having a retransmission function for retransmitting broadcasts, for example, a cradle described in Patent Document 1 is known. This cradle corresponds to a receiving terminal that receives a 2.6 GHz band satellite digital broadcast, and has a retransmission antenna for retransmitting the broadcast, and has a predetermined distance from the receiving antenna of the receiving terminal. They are arranged opposite to each other.

  Also, as a retransmission apparatus that retransmits multimedia broadcasts, a multimedia broadcast re-radiation apparatus described in Patent Document 2 is known. This multimedia broadcast re-radiating apparatus has a re-transmission antenna for re-transmitting the multimedia broadcast, although there is no description of the specific configuration of the charging means, and this re-transmission antenna includes a variable attenuator, a bandpass It is formed as a pattern on a printed circuit board (circuit board) on which an amplifying unit with a filter, a variable gain (AGC: Automatic Gain Control) circuit, and an attenuator are mounted.

JP 2005-109676 A JP 2011-239101 A

  By the way, in the re-transmission device, variable gain operation is required to satisfy the weak radio station regulations stipulated by the Radio Law. If re-transmission is performed before the electric field, the gain variable width in the variable gain amplifier becomes large, causing problems that the circuit scale increases and the cost increases.

  The present invention has been made in view of such circumstances, and provides a retransmission apparatus that can reduce the gain variable width in a gain variable amplifier built in the retransmission apparatus, and can simplify the circuit scale and reduce the cost. With the goal.

  The retransmission apparatus of the present invention includes a variable gain amplifier that amplifies an external input, a detector that controls the gain of the variable gain amplifier based on a detection output obtained by detecting an output from the variable gain amplifier, A retransmission antenna for transmitting the output from the variable gain amplifier supplied via a switch, and when the detection output from the detector is below a level corresponding to a weak radio station stipulated by the Radio Law, The switch is turned on, the output from the variable gain amplifier is supplied to the retransmission antenna via the switch, and the detection output from the detector corresponds to the definition of the weak radio station defined by the Radio Law. When the level is exceeded, the switch is turned off, and the output from the variable gain amplifier is not supplied to the retransmission antenna via the switch.

  According to the above configuration, the output from the variable gain amplifier is retransmitted only when the detection output obtained by detecting the output from the variable gain amplifier is lower than the level corresponding to the weak radio station specified by the Radio Law. Since the antenna is supplied to the antenna, the variable gain width is reduced, and the circuit scale can be simplified and the cost can be reduced.

  In the above configuration, when the detection output from the detector exceeds a level corresponding to the weak radio station specified by the Radio Law, the output terminal of the variable gain amplifier is terminated with a first predetermined impedance. It is characterized by.

  According to the above configuration, radiation from the output terminal of the variable gain amplifier can be suppressed and the definition of the weak radio station defined by the Radio Law can be satisfied. When the gain of the retransmission antenna is low and the output terminal of the variable gain amplifier is open, the radiation from the output terminal of the variable gain amplifier may be larger than the radiation from the retransmission antenna. In such a case, by terminating the output terminal of the variable gain amplifier, radiation from the output terminal of the variable gain amplifier can be reliably suppressed.

  In the above configuration, when the detection output from the detector exceeds a level corresponding to the weak radio station specified by the Radio Law, the input end of the retransmission antenna is terminated with a second predetermined impedance. It is characterized by.

  According to the above configuration, when the detection output from the detector exceeds the level corresponding to the weak radio station specified by the Radio Law, the retransmission antenna is terminated with the second predetermined impedance. Deterioration can be improved. That is, if the retransmission antenna and the antenna on the receiving terminal side are left coupled, the antenna on the receiving terminal side is affected by the retransmission antenna, resulting in performance degradation, so by terminating the retransmission antenna, the receiving terminal side This makes it difficult for the antenna to be affected by the retransmission antenna, and the antenna performance degradation on the receiving terminal side can be improved.

  According to the present invention, the variable gain width in the variable gain amplifier built in the retransmission apparatus can be reduced, and the circuit scale can be simplified and the cost can be reduced.

1 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 1 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. It is a figure for demonstrating the difference of the retransmission apparatus using this invention, and the retransmission apparatus which does not use this invention, (a) shows an example of the input-output characteristic of the retransmission apparatus using this invention FIG. 4B is a diagram illustrating an example of input level versus gain characteristics of a retransmission apparatus using the present invention. It is a figure for demonstrating the difference of the retransmission apparatus which utilizes this invention, and the retransmission apparatus which does not utilize this invention, (a) is an example of the input-output characteristic of the retransmission apparatus which does not utilize this invention FIG. 8B is a diagram illustrating an example of input level versus gain characteristics of a retransmission apparatus that does not use the present invention. The figure which shows an example of the input / output characteristic of a re-transmission apparatus at the time of providing the 1st, 2nd threshold value FIG. 3 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 2 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. FIG. 3 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 3 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. FIG. 5 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 4 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 1 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. In the figure, a retransmission apparatus 1 according to the present embodiment includes an external antenna connection terminal 2, a bandpass filter (BPF) 3, a variable gain amplifier 4, a distributor 5, a switch 6, and a detector 7. A comparator 8, a power feeding unit 9, and a retransmission antenna 10.

  The external antenna connection terminal 2 is a connector for connecting the external antenna 20. The band pass filter 3 blocks a high frequency signal having a wavelength other than the desired wave from the high frequency signals received by the external antenna 20. The variable gain amplifier 4 amplifies the high frequency signal that has passed through the band pass filter 3. The distributor 5 distributes a part (10% or less) of the high-frequency signal amplified by the variable gain amplifier 4 to the detector 7 and distributes the remaining high-frequency signal to the retransmission antenna 10 via the switch 6. The switch 6 outputs and blocks most of the high-frequency signals amplified by the variable gain amplifier 4 and passed through the distributor 5 to the retransmission antenna 10. The high-frequency signal that has passed through the switch 6 is output to the retransmission antenna 10 via the power feeding unit 9.

  The detector 7 detects the high-frequency signal input from the distributor 5 and outputs the obtained voltage to the variable gain amplifier 4 as a gain control signal. The comparator 8 compares the detection output (gain control signal) from the detector 7 with a reference voltage, and outputs a switch control signal for turning on the switch 6 when the detection output is lower than the reference voltage, and the detection output is the reference voltage. If it exceeds, a switch control signal for turning off the switch 6 is output. The reference voltage is a voltage at a level corresponding to the definition of the weak radio station stipulated by the Radio Law. When the detection output from the detector 7 is lower than the level corresponding to the specification of the weak radio station stipulated by the Radio Law, the switch 6 The switch 6 is turned off when the detection output from the detector 7 exceeds the level corresponding to the definition of the weak radio station defined by the Radio Law. When the switch 6 is turned on, the output from the variable gain amplifier 4 is supplied to the retransmission antenna 10 via the switch 6, and when the switch 6 is turned off, the output from the variable gain amplifier 4 is not supplied to the retransmission antenna 10. The receiving terminal 30 receives the broadcast wave by itself through the receiving terminal antenna 32 because the retransmission is not performed from the retransmission apparatus 1 when the broadcast wave is a strong input. As described above, the retransmission state and the self-reception state of the receiving terminal 30 are switched using the definition of the weak radio station defined by the Radio Law as a threshold value.

  The output from the variable gain amplifier 4 is supplied to the re-transmission antenna 10 only when the detection output obtained by detecting the output from the variable gain amplifier 4 is below a level corresponding to the weak radio station stipulated by the Radio Law. Thus, the variable gain width of the variable gain amplifier 4 is reduced. FIG. 2 is a diagram for explaining a difference between a retransmission apparatus 1 using the present invention and a retransmission apparatus (not shown) that is not used. FIG. 2A is a diagram of the retransmission apparatus 1 using the present invention. An example of input / output characteristics, (b) is an example of input level vs. gain characteristics of a retransmission apparatus using the present invention. FIG. 3 is a diagram for explaining a difference between a retransmission apparatus 1 using the present invention and a retransmission apparatus (not shown) that is not used, and (a) is a retransmission that does not use the present invention. An example of the input / output characteristics of the transmission apparatus, (b) is an example of the input level vs. gain characteristics of the retransmission apparatus not using the present invention. 2A and 3A, the horizontal axis represents the input level (dB) and the vertical axis represents the output level (dB). In each of FIG. 2B and FIG. 3B, the horizontal axis represents the input level (dB) and the vertical axis represents the gain (dB). The input level is the signal level at the external antenna connection terminal 2, and the output level is the signal level of the transmission output supplied to the retransmission antenna 10.

  As shown in FIGS. 2 (a) and 2 (b), in the retransmission apparatus 1 using the present invention, the gain takes a constant value when the input level is −90 dB or less, and the gain therebetween is 50 dB. When the input level exceeds −90 dB, the gain gradually decreases thereafter, and when the input level reaches −50 dB, the switch 6 is turned off. Therefore, the variable gain width of the variable gain amplifier 4 of the retransmission apparatus 1 using the present invention is 40 dB. On the other hand, as shown in FIGS. 3A and 3B, in the retransmission apparatus not using the present invention, the gain takes a constant value when the input level is −90 dB or less, and the gain therebetween is 50 dB. ing. When the input level exceeds -90 dB, the gain gradually decreases thereafter, and the input level continues to 0 dB. Therefore, the gain variable width of the retransmission apparatus not using the present invention is 90 dB. Thus, the gain variable width can be reduced by using the present invention. Since the gain variable width is reduced, the circuit scale can be simplified and the cost can be reduced.

  Returning to FIG. 1, the feeding unit 9 is a feeding point of the retransmission antenna 10. The retransmission antenna 10 is an antenna for retransmitting a high frequency signal, and is electromagnetically coupled to the reception terminal antenna 32 of the reception terminal 30 to transmit the high frequency signal to the reception terminal 30.

  In the retransmitting apparatus 1 having such a configuration, when the detection output obtained by detecting the high frequency signal of the broadcast wave received by the external antenna 20 is lower than the level corresponding to the weak radio station stipulated by the Radio Law, A switch control signal for turning on the switch 6 is output from the comparator 8. As a result, the switch 6 is turned on, and the output from the variable gain amplifier 4 (more precisely, the remaining output excluding the amount distributed from the distributor 5 to the detector 7) is supplied to the retransmission antenna 10 and retransmitted. It is transmitted from the antenna 10. The high frequency signal of the transmitted broadcast wave is received by the receiving terminal 30.

  On the other hand, when the detection output obtained by detecting the high frequency signal received by the external antenna 20 exceeds the level corresponding to the weak radio station defined by the Radio Law, the switch control signal for turning off the switch 6 from the comparator 8. Is output. As a result, the switch 6 is turned off, and the output from the variable gain amplifier 4 (more precisely, the remaining output excluding the amount distributed from the distributor 5 to the detector 7) is not supplied to the retransmission antenna 10. That is, when the detection output obtained by detecting the high frequency signal received by the external antenna 20 exceeds the level corresponding to the weak radio station defined by the Radio Law, retransmission is not performed. When the receiving terminal 30 cannot receive the broadcast wave retransmitted from the retransmitting apparatus 1, the receiving terminal 30 receives the broadcast wave by itself.

  As described above, the retransmission apparatus 1 according to the present embodiment switches the switch when the detection output from the detector 7 that detects the output of the variable gain amplifier 4 falls below the level corresponding to the weak radio station defined by the Radio Law. 6 is turned on, the output from the variable gain amplifier 4 is supplied to the retransmission antenna 10 via the switch 6, and the detection output from the detector 7 has a level corresponding to the definition of the weak radio station defined by the Radio Law. In the case of exceeding, the switch 6 is turned off so that the output from the variable gain amplifier 4 is not supplied to the retransmission antenna 10, so that the variable gain width for the variable gain amplifier 4 can be reduced, the circuit scale is simplified, and the cost is low. Can be achieved.

  In the retransmitting apparatus 1 according to the present embodiment, the weak radio station defined by the Radio Law is used as a threshold value to switch between the retransmission state and the self-reception state. A first threshold value that makes a transition to the self-reception state and a second threshold value that makes a transition from the own power reception state to the retransmission state may be provided, and the magnitude relationship between the first and second threshold values may be such that the first threshold value> the second threshold value. The reason for this is that unless the threshold value is changed, if the input level is near the threshold value for switching the switch 6, the switch 6 is frequently switched, and apparently fading occurs, and the reception quality may deteriorate. is there.

  FIG. 4 is a diagram illustrating an example of input / output characteristics of the retransmission apparatus when the first and second thresholds are provided. As described above, by changing the timing of transition from the re-transmission state to the self-reception state and the timing of transition from the self-reception state to the re-transmission state, switching of the switch 6 does not occur frequently, and apparent fading occurs. Is not generated, and reception quality is not deteriorated due to this. Note that the difference between the first threshold value and the second threshold value may be, for example, about 3 to 5 dB at the input level.

(Embodiment 2)
FIG. 5 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 2 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. In the figure, the same reference numerals are given to the portions common to FIG. 1 described above.
When the detection output from the detector 7 exceeds the level corresponding to the definition of the weak radio station defined by the Radio Law, the retransmitting apparatus 1A according to the present embodiment has an output terminal (more precisely, The first predetermined impedance (reactance element or pure resistance, for example, 50Ω) 11 is terminated. In this case, the first predetermined impedance 11 is connected to the output terminal of the variable gain amplifier 4 by the changeover switch 6A.

  When the detection output from the detector 7 exceeds the level corresponding to the weak radio station stipulated by the Radio Law, the changeover switch 6A is switched to connect the output terminal of the variable gain amplifier 4 to the first predetermined impedance 11. Thus, the radiation from the output terminal of the variable gain amplifier 4 is suppressed. That is, it can satisfy the regulations of weak radio stations stipulated by the Radio Law. When the gain of the retransmission antenna 10 is low and the output terminal of the variable gain amplifier 4 is open, the radiation from the output terminal of the variable gain amplifier 4 may be larger than the radiation from the retransmission antenna 10. In such a case, by terminating the output terminal of the variable gain amplifier 4, radiation from the output terminal of the variable gain amplifier can be reliably suppressed.

(Embodiment 3)
FIG. 6 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 3 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. In the figure, the same reference numerals are given to the portions common to FIG. 1 described above.
When the detection output from the detector 7 exceeds the level corresponding to the definition of the weak radio station defined by the Radio Law, the retransmitting apparatus 1B according to the present embodiment is connected to the input terminal of the retransmission antenna 10 (more precisely, The terminal is terminated with a second predetermined impedance (reactance element, for example, Open or pure resistance) 12. In this case, the second predetermined impedance 12 is connected to the input end of the retransmission antenna 10 by the changeover switch 6B.

  When the detection output from the detector 7 exceeds the level corresponding to the weak radio station stipulated by the Radio Law, the selector switch 6B is switched to connect the retransmission antenna 10 to the second predetermined impedance 12 and terminate. Thus, the antenna performance degradation of the receiving terminal 30 can be improved. That is, if the retransmission antenna 10 and the reception terminal antenna 32 on the reception terminal 30 side are left coupled, the reception terminal antenna 32 is affected by the retransmission antenna 10 and performance degradation occurs, so the retransmission antenna 10 is terminated. As a result, the receiving terminal antenna 32 is hardly affected by the retransmission antenna 10, and the antenna performance deterioration can be improved.

(Embodiment 4)
FIG. 7 is a block diagram showing a schematic configuration of a retransmission apparatus according to Embodiment 4 of the present invention and a schematic configuration of a receiving terminal that receives a broadcast wave transmitted from the retransmission apparatus. In the figure, the same reference numerals are given to the portions common to FIGS. 1, 5 and 6 described above.
The retransmitting apparatus 1C according to the present embodiment is a combination of the first predetermined impedance 11 of the second embodiment and the second predetermined impedance 12 of the third embodiment. That is, when the detection output from the detector 7 exceeds the level corresponding to the weak radio station stipulated by the Radio Law, the output terminal of the variable gain amplifier 4 (more precisely, via the distributor 5) is connected to the first. Are terminated at a predetermined impedance 11 and the input end of the re-transmission antenna 10 (to be exact, via the power feeding unit 9) is terminated at a second predetermined impedance 12. In this case, the first predetermined impedance 11 is connected to the output terminal of the variable gain amplifier 4 by the changeover switch 6C, and the second predetermined impedance 12 is connected to the input terminal of the retransmission antenna 10 by the changeover switch 6C. Connected.

  When the detection output from the detector 7 exceeds the level corresponding to the weak radio station stipulated by the Radio Law, the changeover switch 6C is switched to connect the output terminal of the variable gain amplifier 4 to the first predetermined impedance 11. In addition, by terminating the input terminal of the retransmission antenna 10 by connecting to the second predetermined impedance 12, radiation from the output terminal of the variable gain amplifier 4 is suppressed, and the receiving terminal 30 Antenna performance degradation can be improved.

  The present invention has the effect that the variable gain width can be reduced, the circuit scale can be simplified and the cost can be reduced, and can be applied to a retransmission apparatus that retransmits terrestrial digital broadcasts and multimedia broadcasts.

1, 1A, 1B, 1C Retransmission device 2 External antenna connection terminal 3 Bandpass filter 4 Variable gain amplifier 5 Divider 6 Switch 6A, 6B, 6C Changeover switch 7 Detector 8 Comparator 9 Feeder 10 Retransmission antenna 11 1st 1 predetermined impedance 12 second predetermined impedance 20 external antenna 30 receiving terminal 31 feeding unit 32 receiving terminal antenna

Claims (3)

A variable gain amplifier for amplifying an external input;
A detector for controlling a gain of the variable gain amplifier based on a detection output obtained by detecting an output from the variable gain amplifier;
A retransmission antenna for transmitting an output from the variable gain amplifier supplied via a switch, and
When the detection output from the detector falls below a level corresponding to the weak radio station stipulated by the Radio Law, the switch is turned on, and the output from the variable gain amplifier passes through the switch to the retransmission antenna. Supplied to
When the detection output from the detector exceeds a level corresponding to the weak radio station stipulated by the Radio Law, the switch is turned off and the output from the variable gain amplifier is retransmitted via the switch. A retransmission apparatus characterized by not being supplied to an antenna. The retransmission apparatus according to claim 1,
The output terminal of the variable gain amplifier is terminated with a first predetermined impedance when the detection output from the detector exceeds a level corresponding to the weak radio station defined by the Radio Law. Retransmission device. The retransmission apparatus according to claim 1 or 2, wherein
When the detection output from the detector exceeds a level corresponding to the weak radio station defined by the Radio Law, the input end of the retransmission antenna is terminated with a second predetermined impedance. Retransmission device.

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