JP2005079698A - Tuning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a channel selection device capable of selecting both an analog broadcast and a digital broadcast with a simple configuration with respect to a channel selection device for selecting a desired channel from a television broadcast wave.
The present invention relates to a channel selection device (111) for selecting a desired channel from a band including a digital broadcast wave and an analog broadcast wave in a channel selection device (101) for selecting a desired channel from a broadcast wave. 114) and the channel selected by the channel selection circuits (111 to 114) are digital broadcast wave channels, the output signals of the channel selection circuits (111 to 114) are output to the digital broadcast data processing system (116). When the channel selected by the channel selection circuit is an analog broadcast wave channel, the analog broadcast signal processing system (117) has a switch circuit (115) for outputting the output signal of the channel selection circuit. .
[Selection] Figure 1

Description

  The present invention relates to a channel selection apparatus, and more particularly to a channel selection apparatus that selects a desired channel from a television broadcast wave.

  Currently, terrestrial television broadcasting is shifting from analog broadcasting to digital broadcasting. In the transition period from analog broadcasting to digital broadcasting, analog broadcasting and digital broadcasting are mixed. At this time, digital broadcasting has characteristics such as high image quality and high sound quality, and that data communication is possible. In order to take advantage of these characteristics, the contents of the broadcast are different from those of analog broadcasting. Yes. In addition, broadcasting equipment for digital methods is expensive, and analog broadcasting is the mainstay until facilities such as broadcasting equipment for digital broadcasting are prepared. For this reason, the television receiver is desired to be able to receive both analog broadcasting and digital broadcasting during the transition period.

  FIG. 4 is a block diagram showing an example of a VTR that can receive an analog broadcast and a digital broadcast.

  A video tape recorder (VTR) 1 includes an analog broadcast receiving tuner 11, an analog signal processing circuit 12, a digital broadcast receiving tuner 13, a digital data processing circuit 14, and a VTR unit 15.

  FIG. 5 is a block diagram of the analog broadcast receiving tuner 11.

  The analog broadcast receiving tuner 11 is a device for selecting an analog broadcast wave, and includes a UHF channel selection circuit 21, a VHF channel selection circuit 22, a PLL circuit 23, and an analog demodulation circuit 24. A UHF antenna is connected to the UHF antenna terminal Tuhf. A UHF channel selection circuit 21 is connected to the UHF antenna terminal Tuhf. Based on the control voltage from the PLL circuit 23, the UHF channel selection circuit 21 converts the signal of the desired channel from the broadcast wave in the UHF band to an intermediate frequency and outputs the signal. A tuning signal is supplied from the control terminal Tc to the PLL circuit 23, and the control voltage Vc is controlled according to the tuning signal. The intermediate frequency band signal is supplied to the analog demodulation circuit 24 by the UHF channel selection circuit 21 (see Patent Document 1).

  FIG. 6 is a block diagram of the digital broadcast receiving tuner 13. In the figure, the same components as those in FIG.

  The digital broadcast receiving tuner 13 is configured such that a digital demodulation circuit 34 is provided in the analog demodulation circuit 24 of the analog broadcast receiving tuner 11. Since digital broadcasting uses the UHF band and VHF band of the same frequency band as analog broadcasting, the UHF channel selection circuit 21 and the VHF channel selection circuit 22 that perform channel selection have the same configuration.

  The analog demodulated signal of the analog broadcast received by the analog broadcast receiving tuner 11 is supplied to the analog processing circuit 12, subjected to predetermined processing, then supplied to the VTR unit 15, and recorded on a recording medium such as a magnetic tape. Is done.

The digital broadcast digital demodulated data received by the digital broadcast receiving tuner 13 is supplied to a digital data processing circuit 14 and subjected to predetermined processing, and then supplied to a VTR unit 15 for recording on a magnetic tape or the like. Recorded on the medium.
JP 2000-59707 A

  Conventionally, however, in order to receive both analog broadcast and digital broadcast by a television receiver, it is necessary to mount two tuners, an analog broadcast tuner 11 and a digital broadcast tuner 13, in the television receiver. As a result, there were problems such as an increase in the size of the apparatus. There are also problems such as high costs.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a channel selection device that can select both analog broadcast and digital broadcast with a simple configuration.

  In the channel selection device (101) for selecting a desired channel from a broadcast wave, the present invention provides a channel selection circuit (111 to 114) for selecting a desired channel from a band including a digital broadcast wave and an analog broadcast wave; When the channel selected by the channel selection circuit (111 to 114) is a digital broadcast wave channel, the output signal of the channel selection circuit (111 to 114) is output to the digital broadcast data processing system (116) to select the channel selection circuit. When the channel selected in (1) is an analog broadcast wave channel, the analog broadcast signal processing system (117) has a switch circuit (115) for outputting the output signal of the channel selection circuit.

  According to the present invention, tuning and channel selection circuits can be shared between analog broadcasting and digital broadcasting, so that it is possible to configure a tuner that can select both analog broadcasting and digital broadcasting with a simple configuration. There is no need to separately provide a tuner and a digital broadcast tuner, and thus the TV receiver can be miniaturized.

[First embodiment]
FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 2 is an external view of the first embodiment of the present invention.

  As shown in FIG. 2, the channel selection apparatus 101 according to the present embodiment has a configuration in which a circuit board 105 is housed in a shield case 106, which is a so-called tuner unit. From the shield case 106, antenna terminals Tuhf, Tvhf, a control terminal Tc, output terminals Tdout, Taout, and the like protrude.

  A UHF reception antenna 102 is connected to the antenna terminal Tuhf, a VHF reception antenna 103 is connected to the antenna terminal Tvhf, a channel selection controller 104 is connected to the control terminal Tc, and digital broadcast data is received from the digital broadcast output terminal Tdout. The analog broadcast signal is output from the analog broadcast output terminal Taout.

  The channel selection apparatus 101 has a configuration in which a UHF channel selection circuit 111, a VHF channel selection circuit 112, a PLL circuit 113, an IF amplifier 114, a switch circuit 115, a digital processing circuit 116, and an analog processing circuit 117 are mounted on the circuit board 105. ing.

[UHF channel selection circuit 111]
The high frequency signal supplied from the UHF antenna 102 to the antenna terminal Tuhf is supplied to the UHF channel selection circuit 111. The UHF channel selection circuit 111 includes an antenna tuning circuit 121, a high frequency amplifier 122, a high frequency tuning circuit 123, and a frequency converter 124.

  The high frequency signal from the antenna connection terminal Tuhf is first supplied to the antenna tuning circuit 121 in the UHF channel selection circuit 111. The antenna tuning circuit 121 is supplied with a control voltage Vc from the PLL circuit 113. The PLL circuit 113 generates a control voltage Vc according to the channel selection signal supplied from the controller 104 via the control terminal Tc. The antenna tuning circuit 121 varies a frequency characteristic of a built-in filter or the like according to the control voltage Vc from the PLL circuit 113, and extracts a high frequency component in a desired frequency band.

  The high frequency signal output from the antenna tuning circuit 121 is supplied to the high frequency amplifier 122. The high frequency amplifier 122 amplifies and outputs the high frequency signal from the antenna tuning circuit 121. The high frequency signal amplified by the high frequency amplifier 122 is supplied to the high frequency tuning circuit 123. A control voltage Vc is supplied from the PLL circuit 113 to the high frequency tuning circuit 123. The antenna tuning circuit 121 varies the frequency characteristic according to the control voltage Vc from the PLL circuit 113, and further narrows down and extracts a high-frequency component in a desired frequency band.

  The high frequency signal extracted by the high frequency tuning circuit 123 is supplied to the frequency converter 124. The frequency converter 124 includes a voltage controlled oscillation circuit 131 and a mixer 132. The voltage control oscillation circuit 131 is supplied with a control voltage Vc corresponding to the channel selected from the PLL circuit 113. The voltage controlled oscillation circuit 131 varies the oscillation frequency according to the control voltage Vc from the PLL circuit 113. Therefore, the voltage controlled oscillation circuit 131 oscillates at an oscillation frequency corresponding to the selected channel. The output oscillation signal of the voltage controlled oscillation circuit 131 is supplied to the mixer 132.

  In addition to the output oscillation signal of the voltage-controlled oscillation circuit 131, the mixer 132 is supplied with a high-frequency signal from the high-frequency tuning circuit 123. The mixer 132 mixes the output oscillation signal of the voltage controlled oscillation circuit 131 and the high frequency signal from the high frequency tuning circuit 123, and converts the frequency of the high frequency signal from the high frequency tuning circuit 123 into an intermediate frequency band. The signal frequency-converted to the intermediate frequency band is supplied to the IF amplifier 114.

[VHF channel selection circuit 112]
The high frequency signal supplied from the VHF antenna 103 to the antenna terminal Tvhf is supplied to the VHF channel selection circuit 112. The VHF channel selection circuit 112 includes an antenna tuning circuit 141, a high frequency amplifier 142, a high frequency tuning circuit 143, and a frequency converter 144.

  The high frequency signal from the antenna connection terminal Tvhf is first supplied to the antenna tuning circuit 141 in the VHF channel selection circuit 121. A control voltage Vc is supplied from the PLL circuit 113 to the antenna tuning circuit 141. The PLL circuit 113 generates a control voltage Vc according to the channel selection signal supplied from the controller 104 via the control terminal Tc. The antenna tuning circuit 141 varies the frequency characteristics of a built-in filter or the like according to the control voltage Vc from the PLL circuit 113, and extracts a high frequency component in a desired frequency band.

  The output high frequency signal of the antenna tuning circuit 141 is supplied to the high frequency amplifier 142. The high frequency amplifier 142 amplifies the high frequency signal from the antenna tuning circuit 141 and outputs it. The high frequency signal amplified by the high frequency amplifier 142 is supplied to the high frequency tuning circuit 143. A control voltage Vc is supplied from the PLL circuit 113 to the high frequency tuning circuit 143. The antenna tuning circuit 141 varies the frequency characteristic according to the control voltage Vc from the PLL circuit 113, and further narrows down and extracts a high-frequency component in a desired frequency band.

  The high frequency signal extracted by the high frequency tuning circuit 143 is supplied to the frequency converter 144. The frequency converter 144 includes a voltage controlled oscillation circuit 151 and a mixer 152. The voltage controlled oscillation circuit 151 is supplied with a control voltage Vc corresponding to the channel selected from the PLL circuit 113. The voltage controlled oscillation circuit 151 varies the oscillation frequency according to the control voltage Vc from the PLL circuit 113. Therefore, the voltage controlled oscillation circuit 151 oscillates at an oscillation frequency corresponding to the selected channel. The output oscillation signal of the voltage controlled oscillation circuit 151 is supplied to the mixer 152.

  In addition to the output oscillation signal of the voltage controlled oscillation circuit 151, the mixer 152 is supplied with a high frequency signal from the high frequency tuning circuit 143. The mixer 152 mixes the output oscillation signal of the voltage controlled oscillation circuit 131 and the high frequency signal from the high frequency tuning circuit 143, and converts the frequency of the high frequency signal from the high frequency tuning circuit 143 to an intermediate frequency band. The signal frequency-converted to the intermediate frequency band by the frequency converter 144 is supplied to the IF amplifier 114.

[IF amplifier 114]
The IF amplifier 114 amplifies the signal converted into the intermediate frequency band by the frequency converters 124 and 144. The signal amplified by the IF amplifier 114 is supplied to the switch circuit 115.

[Switch circuit 115]
A switch control signal is supplied to the switch circuit 115 from the PLL circuit 113. When the channel selection signal supplied from the controller 104 via the control terminal Tc is a digital broadcast channel, the PLL circuit 113 sets the switching control signal to high level and is supplied from the controller 104 via the control terminal Tc. When the channel selection signal is an analog broadcast channel, the switching control signal is set to a low level. When the switching control signal from the PLL circuit 113 is at a high level, the switch circuit 115 switches the signal path so that the output signal of the IF amplifier 114 is supplied to the digital processing circuit 116, and the switching control signal from the PLL circuit 113. When the signal level is low, the signal path is switched so that the output signal of the IF amplifier 114 is supplied to the analog processing circuit 117. As described above, when the digital broadcast is selected, the output signal of the IF amplifier 114 is supplied to the digital processing circuit 116, and when the analog broadcast is selected, the output signal of the IF amplifier 114 is supplied to the analog processing circuit 117. The

[Digital processing circuit 116]
The digital processing circuit 116 includes a SAW filter 161 and a digital demodulation circuit 162. The SAW filter 161 extracts a signal having a desired frequency component from the intermediate frequency signal supplied from the switch circuit 115. The signal extracted by the SAW filter 161 is supplied to the digital demodulation circuit 162.

  The digital demodulation circuit 162 digitally processes the signal supplied from the SAW filter 161 and demodulates the MPEG2-TS signal. The MPEG2-TS signal demodulated by the digital demodulation circuit 162 is output from the output terminal Tdout.

[Analog processing circuit 117]
The analog processing circuit 117 includes a SAW filter 171 and an analog demodulation circuit 172. The SAW filter 171 extracts a signal having a desired frequency component from the intermediate frequency signal supplied from the switch circuit 115. The signal extracted by the SAW filter 171 is supplied to the analog demodulation circuit 172.

  The analog demodulation circuit 172 performs FM demodulation on the signal supplied from the SAW filter 171 and demodulates it into a composite video signal and an audio signal. The composite video signal and audio signal demodulated by the analog demodulation circuit 172 are output from the output terminal Taout.

  In this way, digital broadcasting and analog broadcasting can be received using the common UHF channel selection circuit 111. At this time, a switch circuit 115 is provided to supply the output signal of the IF amplifier 114 to the digital processing circuit 116 when receiving the digital broadcast, and to supply the output signal of the IF amplifier 114 to the analog processing circuit 117 when receiving the analog broadcast. The digital processing circuit 116 and the analog / digital processing circuit 117 can be isolated, and noise can be prevented from being mixed due to crosstalk.

  In this embodiment, the channel selection apparatus 101 is provided with both the digital demodulation circuit 116 and the analog demodulation circuit 117. However, the analog demodulation circuit 117 may be an external component (IC).

[Second Embodiment]
FIG. 3 shows a block diagram of the second embodiment of the present invention. In the figure, the same components as in FIG.

  The channel selection device 201 of this embodiment is configured such that the analog demodulation circuit 117 is deleted from the channel selection device 101 shown in FIG. 1 and an IF signal is output from the analog output terminal Taout. According to the channel selection apparatus 201 of the present embodiment, the channel selection apparatus 201 can be provided at a low cost when the analog demodulation circuit 117 that demodulates analog broadcast is deleted and mounted on a digital broadcasting dedicated machine or the like.

It is a block block diagram of 1st Example of this invention. It is an external view of 1st Example of this invention. It is a block block diagram of 2nd Example of this invention. It is a block diagram of an example of VTR which can receive analog broadcasting and digital broadcasting. 2 is a block configuration diagram of an analog broadcast receiving tuner 11. FIG. 2 is a block configuration diagram of a digital broadcast receiving tuner 13. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Channel selection apparatus, 102 UHF antenna, 103 VHF antenna 104 Channel selection controller 111 UHF channel selection circuit, 112 VHF channel selection circuit, 113 PLL circuit 114 IF amplifier, 115 switch circuit, 116 Digital processing circuit 121 Analog processing circuit 121, 141 Antenna tuning circuit, 122, 142 High frequency amplifier 123, 143 High frequency tuning circuit, 124, 144 Frequency converter 131, 151 Voltage controlled oscillation circuit, 132, 152 Mixer 161, 171 SAW filter, 162 Digital demodulation circuit 172 Analog demodulation circuit

Claims (5)

In a channel selection device that selects a desired channel from a broadcast wave,
A channel selection circuit for selecting a desired channel from a band including a digital broadcast wave and an analog broadcast wave;
When the channel selected by the channel selection circuit is the channel of the digital broadcast wave, an output signal of the channel selection circuit is output to the digital data processing system, and the channel selected by the channel selection circuit is the analog broadcast A channel selection apparatus comprising a switch circuit for outputting an output signal of the channel selection circuit to an analog signal processing system for a wave channel. When the digital data processing system is selected by the switch circuit, an output signal is supplied from the channel selection circuit, and a digital demodulation circuit that digitally demodulates the output signal from the channel selection circuit;
The analog demodulating circuit which receives an output signal from the channel selection circuit and analog-demodulates the output signal from the channel selection circuit when the analog processing system is selected by the switch circuit. 1. The channel selection device according to 1. When the digital data processing system is selected by the switch circuit, an output signal is supplied from the channel selection circuit, and a digital demodulation circuit that digitally demodulates the output signal from the channel selection circuit,
2. The channel selection apparatus according to claim 1, wherein when the analog data processing system is selected by the switch circuit, an output signal is output as it is from the channel selection circuit. The channel selection circuit includes a first tuning circuit that tunes to an ultra-short wave band;
4. The channel selection device according to claim 1, further comprising: a second tuning circuit that tunes to an ultra-high frequency band. 5. A channel selection device capable of selecting a desired channel from digital broadcasting and analog broadcasting,
A channel selection circuit for selecting a desired channel from digital broadcasting and a channel selection circuit for selecting a desired channel from analog broadcasting are commonly used. Station equipment.

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