KR100199879B1 - Rf amplifying shared apparatus of television tuner - Google Patents

Abstract

A high-frequency filter (24) for filtering and passing a high-frequency signal from an RF signal of a television broadcast transmitted to a receiving antenna (22), and a high-frequency filter A UHF band filter 28 for filtering and passing only the UHF band in the high frequency filtered RF signal, an optional switching control signal SC1 for selecting the VHF band and the UHF band, A switch unit 30 for receiving the RF signal of the VHF band from the VHF bandpass filter 26 or the UHF band RF signal from the UHF bandpass filter 28 selectively, A single RF amplifying unit 32 that receives a RF signal in the VHF band and an RF signal in the UHF band and performs common high frequency amplification operation by the gain control of the AGC voltage, a channel for channeling a predetermined channel in the VHF band, line A VHF inter-phase tuning unit 34 for receiving a voltage VT1 and selecting an RF signal of a corresponding channel from an RF signal according to the VHF band amplified by the single RF amplifying unit 32, a predetermined channel of the UHF band A UHF inter-phase tuning unit 36 for receiving a channel selection voltage VT2 for tuning and tuning an RF signal of a corresponding channel from an RF signal according to a UHF band amplified by the single RF amplifying unit 32, A signal mixer 40 which mixes a local oscillation frequency signal generated from the oscillation unit 38 with an RF signal selected by the VHF interphase tuner 34 or the UHF interphase tuner 36 to generate an intermediate frequency signal, A channel selection channel VT1 for selecting a predetermined channel in the VHF band or a channel selection channel VT2 for channel selection in the UHF band is generated by the channel selection data memorized in the channel data memory 44, (34) or the UHF interphase tuning unit (36) And a microcomputer 46 for generating switching control signals SC1 and SC2 to the switch unit 30 corresponding to the channel selection state of the VHF band or the UHF band.

Description

RF amplifier sharing device of television tuner

[0001] The present invention relates to an RF amplifying and sharing apparatus for a television tuner, and more particularly, to an RF amplifying and sharing apparatus for tuning RF amplifying means for tuning an RF signal according to a television broadcast of a predetermined channel on a television in cooperation with a VHF channel and a UHF channel To an RF amplifier commoning device of a television tuner.

Currently, in a commonly used television, a broadcasting signal of a desired channel is selected among a plurality of broadcasting RF signals of a plurality of channels induced in a receiving antenna, and a video signal processing and an audio signal processing operation are performed to output a video signal through a CRT So that a channel selection system made up of a tuner is selected for tuning a television broadcast of such a desired channel.

On the other hand, according to the channel selection system made up of such a tuner, a television of a very high frequency (VHF) channel of 12 channels, such as a VHF high band of 90 to 108 MHz and a VHF low band of 170 to 222 MHz, A broadcasting signal of a UHF (Ultra High Frequency) channel of 50 channels such as a broadcasting signal and a UHF band of 470 to 770 MHz can be tuned. In addition, an input circuit connected to a receiving antenna eliminates unnecessary signals, The amplification operation is performed to improve the SN (Signal To Noise) ratio through the high frequency amplifying circuit, and the television broadcasting signal is converted into the form of the IF signal A local oscillation signal whose frequency is set according to a desired channel and a broadcast RF signal corresponding to the desired channel are heterodyned.

Further, the frequency of the local oscillation signal is usually controlled by the tuning voltage, and the tuning voltage can be generated by a voltage synthesizing method or a frequency synthesizing method corresponding to channel selection by the viewer.

In addition, an AFT (Auto Fine Tuning) circuit is provided to automatically fine-tune the frequency of the image intermediate frequency signal so that the frequency of the image intermediate frequency signal is accurately adjusted so that the CRT device can output the image in an optimal screen form. In such an AFT circuit, after an image carrier from an image intermediate frequency amplifier stage is detected and amplified to remove unnecessary frequency bands, the signal component according to the result is amplified by a tuning system such as a variable capacitance diode , It is possible to correct the local oscillation frequency by applying it to the local oscillation circuit of the tuner.

According to the channel selection system composed of such a tuner, as shown in Fig. 1, there are provided a reception antenna 2 for receiving television carrier signals of a plurality of channels transmitted from a plurality of television broadcasting stations, A first band-pass filter (6) for filtering and passing only a VHF frequency band from an RF signal of the high-frequency-filtered television broadcast, and a second band-pass filter A first RF amplifier 8 for selecting / amplifying a signal of a desired channel in an RF signal of a television broadcast according to the VHF band to improve an S / N (Signal / Noise) ratio, A first terminal-to-terminal tuning circuit for receiving a channel selection voltage (VT) generated according to a selection of a predetermined VHF channel and selecting an RF signal of the corresponding channel from the amplified RF signal, A second band-pass filter 12 for filtering and passing only the UHF frequency band of the RF signal of the high-frequency filtered television broadcast, a signal of a desired channel in the RF signal of the television broadcast according to the filtered UHF band, A second RF amplifying unit 14 for selecting and amplifying a signal to noise ratio (S / N) ratio, and a channel selection terminal (VT) generated in response to the selection of a predetermined UHF channel from control means A second end tuning unit 16 for tuning the RF signal of the corresponding channel in the amplified RF signal, a second end tuning unit 16 for converting the RF signal of the tuned television broadcast to the intermediate frequency form A local oscillation unit 18 for generating a predetermined local oscillation frequency signal and a signal mixing unit 20 for mixing an RF signal of the selected channel and a local oscillation frequency signal to generate an intermediate frequency signal of 58.75 MHz.

In a channel selection system composed of such components, when a channel selection terminal voltage (VT) for tuning a channel of the VHF band is supplied from the control means (not shown), the first band-pass filter 6, the RF signal of the VHF band is filtered and amplified by the first RF amplifying unit 8, the first end tuning unit 10 adjusts the RF of the corresponding channel by the inductance due to the channel tuning voltage VT The RF signal of the selected VHF band channel is mixed with the local oscillation frequency signal of the local oscillation section 18 in the signal mixing section 20 and is mixed with the local oscillation frequency signal of the local oscillation section 18 to the intermediate frequency amplification means (not shown) side .

On the other hand, when the channel selection voltage VT for channeling the UHF band is supplied from the control means, the high frequency band passes by the high frequency filter 4 and the RF signal of the UHF band in the second band filter 12 The RF signal of the corresponding channel is tuned in accordance with the change in capacitance due to the channel selection voltage VT of the second end tuning unit 10, The RF signal of the selected UHF band channel is mixed with the local oscillation frequency signal of the local oscillation section 18 in the signal mixing section 20 and output to the intermediate frequency amplification means (not shown) side as an intermediate frequency signal.

However, in the channel selection system composed of such a tuner, since separate RF amplification circuits are provided for the RF signal for the channel selection channel in the VHF band and the RF signal for the channel selection channel in the UHF band, respectively, There is a disadvantage that the configuration circuit of the system is complicated and the manufacturing cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and provides an RF amplifying and sharing apparatus of a television tuner which is equipped with a single RF amplifying means to a tuner of a television so as to commonly amplify RF signals of a VHF channel and a UHF channel There is a purpose.

According to an aspect of the present invention, there is provided an RF amplifier sharing apparatus for a television tuner, comprising: a high-frequency filter for filtering and passing a high-frequency signal from an RF signal of a television broadcast transmitted through a receiving antenna; A VHF band filter for filtering and passing only the VHF band, a UHF band filter for filtering and passing only the UHF band in the high frequency filtered RF signal, a VHF band filter for receiving the selective switching control signal selected by the VHF band and the UHF band, A UHF band RF signal from the VHF band or a UHF band RF signal from the UHF band filter, and a gain control unit for receiving the RF signal of the VHF band and the RF signal of the UHF band, A single RF amplifying unit commonly used for high frequency amplifying operation, a channel line localizing unit for selecting a predetermined channel in the VHF band, A VHF inter-phase tuning unit for tuning an RF signal of a corresponding channel in an RF signal according to the VHF band amplified by the single RF amplifying unit by the single RF amplifying unit, a channel selecting unit for receiving a channel selecting signal for selecting a predetermined channel in the UHF band, A UHF inter-phase tuning unit for tuning an RF signal of the corresponding channel in an RF signal according to a UHF band amplified by the RF amplifying unit of the UHF band, a local oscillation frequency signal generated from the local oscillation unit, and a VHF inter- A channel mixer for mixing the tuned RF signals and generating an intermediate frequency signal and a channel selection channel for channel tuning for a predetermined channel in the VHF band or a predetermined channel in the UHF band according to channel tuning data memorized in the channel data memory Generates a channel selection voltage and supplies it to the VHF inter-phase tuning unit or the UHF inter-phase tuning unit, and also responds to the channel selection state of the VHF band or the UHF band By having a W microcomputer for generating a switching control signal to the switch unit provides a RF amplifier sharing apparatus of the television tuner configured.

Preferably, the switch unit is connected to the output terminal of the VHF band filter, and the switch unit is connected to the first diode end connected to the output terminal of the VHF band filter, Supply of RF signals according to the UHF band is determined according to the signal level of the switching control signal from the microcomputer, which is input through a resistor between the second diode ends forwardly connected to the output terminal of the UHF band filter, Whether or not it is determined to be determined.

According to the present invention configured as described above, a single RF amplifying circuit for high-frequency amplifying RF signals in the VHF band and the UHF band in the television tuner is commonly used to broadcast channels in the VHF band or the UHF band And the RF signal is selectively supplied according to the selection, so that the RF amplification operation is performed.

1 is a block diagram showing the configuration of a conventional television tuner,

2 is a block diagram showing an RF amplifying and sharing apparatus of a television tuner according to the present invention,

3 is a detailed circuit diagram of the switching unit and the RF amplifying unit shown in FIG.

Description of the Related Art [0002]

22: receiving antenna 24: high frequency filter,

26: VHF band filter 28: UHF band filter,

30: switch unit 32: RF amplifier unit,

34: VHF inter-phase tuning unit 36: UHF inter-phase tuning unit,

38: Local oscillator 40: Signal mixer,

42: Function setting section 44: Channel data memory,

46: Micom 48: Field effect transistor,

R1 to R8: Resistors C1 to C4: capacitors,

D1, D2: Diode

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating an apparatus for sharing an RF amplifier of a television tuner according to the present invention. In the apparatus of the present invention, reference numeral 24 denotes a VHF band induced in the receiving antenna 22 and a plurality of channels Shows a high-frequency filter that filters and passes only a high-frequency band in a television carrier signal.

Reference numeral 26 denotes a VHF band filter for filtering and passing only RF signals according to the high frequency filtered VHF band and 28 denotes a UHF band filter for filtering and passing only RF signals according to the high frequency filtered UHF band.

Reference numeral 30 denotes a switch for receiving switching control signals SC1 and SC2 corresponding to channel selection states of a VHF band broadcast channel and a UHF band broadcast channel from a microcomputer 46 to be described later, 26, and RF signal from the UHF band filter 28. Reference numeral 32 denotes a switch unit for selectively transmitting the RF signal in the VHF band selectively applied by the switch unit 30 and the RF signal in the UHF band 28, And a single RF amplifying unit for commonly high-frequency amplifying the signal.

3, the first diode D1 is connected to the output terminal of the VHF band filter 26 and the output terminal of the UHF band filter 28 is connected to the output terminal of the UHF band filter A diode D2 is connected in a forward direction and a switching control signal SC1 from a microcomputer 46, which will be described later, is connected between the output terminal of the VHF bandpass filter 26 and the input terminal of the first diode D1, And a switching control signal SC2 from a microcomputer 46 to be described later is input between the output terminal of the UHF bandpass filter 28 and the input terminal of the second diode D2 via a resistor R2 do.

3, the first amplifying unit 32 has a first gate terminal connected in common to the first and second diodes D1 and D2 via a capacitor C1, A gate terminal is connected between the resistor R5 and an end of the capacitor C2 to receive an AGC (Automatic Gain Control) voltage for controlling the gain of the input signal and the source terminal thereof is connected to the power source B + And a field effect transistor 48 whose drain terminal is connected to the input terminal of the VHF inter-phase tuning unit 34 and the UHF inter-phase tuning unit 36 via a capacitor C4.

Reference numeral 34 denotes a VHF amplifier which receives the channel selection data VT1 for tuning a predetermined channel in the VHF band from the microcomputer 46 to be described later, 36 denotes a channel selection data VT2 for selecting a predetermined channel in the UHF band from a microcomputer 46 to be described later, and receives a channel selection data VT2 from the microcomputer 46, And tunes the RF signal of the desired channel in the RF signal of the UHF band amplified by the RF amplifier 32 by the RF amplifier 32. [

Reference numeral 38 denotes a local oscillation unit for generating a predetermined local oscillation frequency signal by the channel selection data VT1 and VT2 and reference numeral 40 denotes a local oscillation frequency signal and a VHF from the VHF inter-phase tuning unit 34 Band RF signal or the UHF RF signal from the UHF inter-phase tuning unit 36 to generate an intermediate frequency signal of 58.75 MHz.

Reference numeral 42 denotes a remote controller for remote control or a matrix button provided in the control panel unit of the main body, and indicates a function setting unit having a 10-key and a channel shortening selection key for key operation for selecting a predetermined channel.

Reference numeral 44 denotes a channel data memory for storing channel selection data for selecting a plurality of broadcast channels in the VHF band and the UHF band, 46 is a microcomputer for controlling the overall functional operation of the television, The microcomputer 46 sets the channel selection voltage VT1 for channel selection in the VHF band based on the channel selection data from the channel data memory 44 to tune to a predetermined channel selected by the function setting unit 42. [ Or the UHF band channel selection channel VT2 and generates switching control signals SC1 and SC2 having mutually inverted signal levels corresponding to the channel selection state of the switch unit 30 .

Here, when the microcomputer 46 tunes to a VHF band broadcast channel, the microcomputer 46 sets the switching control signal SC1 as a low level signal and the switching control signal SC2 as a high level signal, When the channel is tuned, the switching control signal SC1 is set to the high level signal and the switching control signal SC2 is set to the low level signal.

The operation of the present invention as described above will now be described in detail with reference to the accompanying drawings.

First, in the case of selecting a broadcast channel in the VHF band, for example, by the key operation of the function setting section 42 in the power-on state of the television, the microcomputer 46 recognizes the channel selection state of the function setting section 46 The channel selection data VT1 for selecting a broadcast channel in the VHF band is generated by the channel selection data of the channel data memory 44 and the low level switching control signal SC1 and the high level switching control signal SC2, respectively.

In this state, only the high-frequency signal is filtered by the high-frequency filter 24, and the RF signal filtered only through the VHF band filter 26 is filtered through the first diode Dl of the switch unit 30 into a single Is applied to the first gate terminal of the field effect transistor 48 of the RF amplifying section 32 and the AGC voltage is applied to the field effect transistor 48 through the second gate terminal thereof, The VHF inter-phase tuning unit 34 receives the channel tuning voltage VT1 from the microcomputer 46 and generates a change in inductance capacitance, The RF signal of the desired channel is selected from the RF signal of the VHF band from the RF amplifier 32. The signal mixer 40 mixes the RF signal of the selected channel with the local oscillation of the local oscillator 38, Intermediate frequency signal mixed with frequency signal It is generated.

When the channel setting of the UHF band is performed by the function setting unit 42, the microcomputer 46 sets the channel tuning voltage for channel tuning in the UHF band according to the channel data of the channel data memory 44 Level switching control signal SC1 and a low-level switching control signal SC2, as shown in FIG.

The switch unit 30 receives the RF signal filtered through the high frequency filter 24 and filtered only by the UHF band by the UHF band filter 28 via the second diode D2 The RF input signal is input to the first gate terminal of the field effect transistor 48 provided in the single RF amplifying unit 32 and the UHF band RF signal is amplified and output through the drain terminal of the field effect transistor 48 The RF signal of the desired channel is tuned in accordance with the channel tuning voltage VT2 by the UHF inter-phase tuning unit 36 in the signal, and the tuned RF signal is supplied to the local oscillation unit 38 by the signal mixing unit 40. [ And is output as an intermediate frequency signal.

According to the present invention as described above, the RF signal according to the channel selection channel of the VHF rental and the RF signal according to the channel selection channel of the UHF band can be shared by the single RF amplifying circuit in the television tuner Accordingly, the circuit configuration inside the tuner can be simplified, and the manufacturing cost can be reduced.

Claims (2)

A high frequency filter 24 for filtering and passing a high frequency signal from an RF signal of a television broadcast induced in the receiving antenna 22, A VHF band filter 26 for filtering and passing only the VHF band from the high frequency filtered RF signal, A UHF band filter 28 for filtering and passing only the UHF band in the high frequency filtered RF signal, VHF band and UHF band, and receives the RF signal of the VHF band from the VHF band filter 26 or the RF signal of the UHF band from the UHF band filter 28 in response to the selective switching control signals SC1 and SC2 by the channel selection of the UHF band and the UHF band. A switch unit 30 for selectively passing the light- A single RF amplifying unit 32 for receiving the RF signal of the VHF band and the RF signal of the UHF band which have passed through the switch unit 30 and commonly performing high frequency amplification operation by controlling the gain of the AGC voltage, VHF inter-stage tuning in which an RF signal corresponding to a VHF band is selected from an RF signal according to a VHF band amplified by the single RF amplifying unit 32 by receiving a channel selection voltage VT1 for selecting a predetermined channel in the VHF band, (34), A UHF inter-stage tuning circuit for receiving a channel selection voltage (VT2) for tuning a predetermined channel in the UHF band and selecting an RF signal of the corresponding channel from an RF signal according to a UHF band amplified by the single RF amplifying unit Section 36, A signal mixing unit 40 which mixes a local oscillation frequency signal generated from the local oscillation unit 38 with an RF signal selected by the VHF inter-phase tuning unit 34 or the UHF inter-phase tuning unit 36 to generate an intermediate frequency signal, , A channel selection channel VT1 for selecting a predetermined channel in the VHF band or a channel selection channel VT2 for channel selection in the UHF band is generated by the channel selection data memorized in the channel data memory 44, And supplies the switching control signals SC1 and SC2 to the switching unit 30 in response to the channel selection state of the VHF band or the UHF band, 46). The television tuner according to claim 1 or 2, further comprising: The VHF band pass filter according to claim 1, wherein the switch unit (30) comprises a first diode (D1) connected in forward direction with respect to an output terminal of the VHF band filter (26) The supply of the RF signal according to the VHF band is determined according to the signal level of the switching control signal SC1 from the first diode D2 connected to the output terminal of the UHF bandpass filter 28, Wherein whether to supply the RF signal according to the UHF band is determined according to the signal level of the switching control signal (SC2) input from the microcomputer (46) via the resistor (R2) Amplification sharing device.