KR19980017760A - RF Amplifier Common Unit for Television Tuner - Google Patents

Abstract

The present invention relates to an RF amplification sharing apparatus for a television tuner, comprising: a high frequency filter (24) for filtering high frequency signals from RF signals of television broadcasting induced by a receiving antenna (22), and a VHF in the high frequency filtered RF signals. VHF band filter 26 for filtering and passing only the band, UHF band filter 28 for filtering and passing only the UHF band from the high frequency filtered RF signal, and a selective switching control signal (SC1) by selecting stations of the VHF band and the UHF band. A switch unit 30 for selectively passing 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 by receiving the SC2; A single RF amplification unit 32, which is operated by a high frequency amplification operation in common by the gain control of the AGC voltage by receiving the RF signal of the VHF band and the RF signal of the UHF band passing through), and a channel for selecting a predetermined channel of the VHF band line A VHF inter-terminal tuning unit 34 for tuning an RF signal of a corresponding channel from an RF signal according to a VHF band amplified by the single RF amplifier 32 by receiving a voltage VT1, and a predetermined channel of a UHF band. UHF inter-terminal tuning unit 36 for tuning the RF signal of the corresponding channel in the RF signal according to the UHF band amplified by the single RF amplifier 32 by receiving the channel tuning voltage VT2 for tuning A signal mixer 40 for mixing the local oscillation frequency signal generated from the oscillator 38 and the RF signal tuned by the VHF inter-terminal tuning unit 34 or the UHF inter-terminal tuning unit 36 to generate an intermediate frequency signal; The channel tuning voltage VT1 for channel presetting in the VHF band or the channel tuning voltage VT2 for tuning the predetermined channel in the UHF band is generated by the channel tuning data stored in the channel data memory 44. In addition to supplying the part 34 or the UHF short interlocking part 36 For example, the switch unit 30 is provided with a microcomputer 46 for generating switching control signals SC1 and SC2 in response to the channel selection state of the VHF band or the UHF band.

Description

RF Amplifier Common Unit for Television Tuner

The present invention relates to an RF amplification sharing apparatus for a television tuner. More particularly, the RF amplifying means of a tuner which tunes an RF signal according to a television broadcasting of a predetermined channel in a television can be shared with a VHF channel and a UHF channel. The present invention relates to an RF amplifier sharing apparatus for a television tuner.

Currently, in a television which is generally used, a broadcast signal of a desired channel is tuned among a multi-channel broadcast RF signal induced by a receiving antenna, and the video signal processing and audio signal processing operations are performed to output a video through a CRT device. As a result, the channel selection system consisting of a tuner is adopted to tune the television broadcast of the desired channel.

On the other hand, according to the channel tuning system composed of such tuners, televisions of 12 channels of VHF (Very High Frequency) channels such as VHF high band of 90 to 108 MHz and VHF low band of 170 to 222 MHz including video information and audio information are included. Broadcast signals and television broadcast signals of 50 UHF (Ultra High Frequency) channels, such as the 470-770 MHz UHF band, can be tuned, as well as the elimination of unnecessary signals and high frequency from the input circuit connected to the receiving antenna. The amplification operation is performed to match the input impedance of the amplification, and to improve the signal to noise (SN) ratio through the high frequency amplification circuit, and converts the television broadcast signal into the form of an IF signal. In order to generate, a heterogeneous local oscillation signal whose frequency is set according to a desired channel and a broadcast RF signal according to the desired channel are heterogeneous.

In addition, the frequency of the local oscillation signal is normally controlled by the tuning voltage, while the tuning voltage can be generated by the voltage synthesis method or the frequency synthesis method in response to channel selection by the viewer.

In addition, an AFT (Auto Fine Tunning) circuit is automatically provided to automatically adjust the frequency of the image intermediate frequency signal to 58.75 MHz so that the CRT device can output an image in an optimal screen form. In such AFT circuits, FM signals are detected and amplified from the image intermediate frequency amplifier stages, filtered to remove unnecessary frequency bands, and the resulting signal components are tuned to a tuning system such as a variable capacitance diode. In addition, the local oscillation frequency can be corrected by applying the tuner to the local oscillation circuit.

According to the channel tuning system composed of such a tuner, as shown in FIG. 1, a reception antenna 2 in which a plurality of channels of television carrier signals transmitted from a plurality of television broadcasting stations are induced and a reception antenna 2 are inferred in the reception antenna 2; A high frequency filter 4 comprising a high pass filter for filtering only a high frequency band in a television carrier signal, a first band filter 6 for filtering and passing only a VHF frequency band in an RF signal of the high frequency filtered television broadcast, and the filtering From the first RF amplifier 8, control means (not shown) for selecting / amplifying a signal of a desired channel from the RF signal of the television broadcasting according to the VHF band to improve the signal / noise ratio. A first stage tuning for receiving a channel selection voltage (VT) generated according to the selection of a predetermined VHF channel and tuning the RF signal of the corresponding channel from the amplified RF signal. A second band filter 12 for filtering and passing only the UHF frequency band from the RF signal of the high frequency filtered television broadcast, and receiving a signal of a desired channel from the RF signal of the television broadcast according to the filtered UHF band. Input channel selector voltage (VT) generated according to the selection of a predetermined UHF channel from the second RF amplifier 14, control means (not shown) to select / amplify to improve the S / N (Signal / Noise) ratio. The second stage interlocking unit 16 which receives and tunes an RF signal of a corresponding channel from the amplified RF signal, receives the channel tuning voltage VT, and converts the RF signal of the tuned television broadcast into an 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 the channel tuning system composed of such components, when the channel tuning voltage VT for tuning the channel of the VHF band is supplied from the control means (not shown), the first band filter ( In 6), when the RF signal of the VHF band is filtered and amplified by the first RF amplifier 8, the first inter-step tuning unit 10 causes the RF of the corresponding channel to be changed by the inductance caused by the channel tuning voltage VT. The signal is tuned, and the RF signal of the tuned VHF band channel is mixed with the local oscillation frequency signal of the local oscillation unit 18 in the signal mixing section 20 to an intermediate frequency amplification means (not shown) as an intermediate frequency signal. Is output.

On the other hand, when the channel selection voltage VT for tuning the channel of the UHF band is supplied from the control means, the high frequency band passes through the high frequency filter 4 and the RF signal of the UHF band is passed by the second band filter 12. Is filtered and amplified by the second RF amplifier 8, the second inter-step tuning unit 10 tunes the RF signal of the corresponding channel by a change in the capacitance of the channel tuning voltage VT. The RF signal of the tuned UHF band channel is mixed with the local oscillation frequency signal of the local oscillation unit 18 in the signal mixing section 20 and output as an intermediate frequency signal to an intermediate frequency amplifier means (not shown).

However, in the channel tuning system composed of such tuners, separate RF amplification circuits are provided for the RF signal for the tuning channel of the VHF band and the RF signal for the tuning channel of the UHF band, so that a circuit element having the same function is further provided. As a result, the system circuit becomes complicated and the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a television tuner RF amplification apparatus for providing a single RF amplification means in a television tuner so that RF signals of a VHF channel and a UHF channel can be amplified in common. There is a purpose.

According to the RF amplification sharing apparatus of the television tuner according to the present invention in order to achieve the above object, a high frequency filter for filtering and passing a high frequency signal in the RF signal of the television broadcast is received in the receiving antenna, and the high frequency filtered RF signal VHF band filter for filtering and passing only the VHF band, UHF band filter for filtering and passing only the UHF band from the high frequency filtered RF signal, VHF band filter by receiving a selective switching control signal by the station of the VHF band and UHF band A switch unit for selectively passing the RF signal of the VHF band from the UHF band or the RF signal of the UHF band from the UHF band filter, and the gain control of the AGC voltage by receiving the RF signal of the VHF band and the RF signal of the UHF band passing through the switch unit. A single RF amplification unit for high frequency amplification operation by means of a channel, and channel tuning for tuning a predetermined channel in the VHF band. A single VHF inter-tuner for tuning an RF signal of a corresponding channel in an RF signal according to a VHF band amplified by the single RF amplifier and receiving a channel selection voltage for tuning a predetermined channel of a UHF band In the UHF stage inter-tuner, which tunes the RF signal of the corresponding channel from the RF signal according to the UHF band amplified by the RF amplifier of the local oscillation frequency signal generated from the local oscillator, A channel mixing voltage for mixing a predetermined channel of a VHF band or a channel for tuning a predetermined channel of a UHF band by a signal mixing unit which mixes the tuned RF signal to generate an intermediate frequency signal and channel tuning data stored in the channel data memory. Generates a preset voltage and supplies it to the VHF inter-step tuning unit or the UHF inter-step tuning unit and corresponds to the channel tuning 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 configured to convert the RF signal according to the VHF band according to the signal level of the switching control signal from the microcomputer, which is input via a resistance between the first diode terminals connected forward to the output terminal of the VHF band filter. Supply of the RF signal according to the UHF band is determined according to the signal level of the switching control signal from the micom inputted through the resistance between the second diode terminal connected forward to the output terminal of the UHF band filter. It is characterized in that it is configured to determine whether or not.

According to the present invention configured as described above, a broadcast channel of the VHF band or the UHF band is used in a tuner of a television by using a single RF amplifier circuit which is used for amplifying the RF signal of the VHF band and the RF signal of the UHF band in common. As the channel is tuned, the RF signal is selectively supplied with the RF signal.

1 is a block diagram showing a configuration of a conventional general television tuner;

2 is a block diagram showing an RF amplifier sharing apparatus for a television tuner according to the present invention;

3 is a diagram illustrating a detailed circuit configuration of the switching unit and the RF amplifier shown in FIG. 2.

Explanation of symbols on the main parts of the drawings

22: receiving antenna 24: high frequency filter,

26: VHF band filter 28: UHF band filter,

30: switch part 32: RF amplification part,

34: VHF single phase tuning part 36: UHF single phase tuning part,

38: local oscillation unit 40: signal mixing unit,

42: function setting section 44: channel data memory,

46: microcomputer 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 showing an RF amplifier sharing apparatus of a television tuner according to the present invention. In the apparatus of the present invention, reference numeral 24 denotes a plurality of channels according to the VHF band and the UHF band induced in the receiving antenna 22. A high frequency filter for filtering and passing only a high frequency band in a television carrier signal.

In addition, reference numeral 26 denotes a VHF band filter for filtering and passing only the RF signal according to the high frequency filtered VHF band, and 28 denotes a UHF band filter for filtering and passing only the RF signal according to the high frequency filtered UHF band.

Further, reference numeral 30 is a switch operation by receiving switching control signals SC1 and SC2 corresponding to the tuning state of the VHF band broadcast channel or the UHF band broadcast channel from the microcomputer 46 to be described later. 26 shows a switch section for selectively passing the RF signal from the UHF band filter 28 or RF signal from the UHF band filter 28, and 32 denotes an RF signal of the VHF band and an RF of the UHF band selectively applied by the switch section 30. Represents a single RF amplifier that jointly amplifies a signal.

Here, as illustrated in FIG. 3, the switch unit 26 has a first diode D1 connected to the output terminal of the VHF band filter 26 in a forward direction, and the output terminal of the UHF band filter 28. The two diodes D2 are forward-connected so that the switching control signal SC1 from the microcomputer 46 described later is connected between the output terminal of the VHF band filter 26 and the input terminal of the first diode D1. The switching control signal SC2 from the microcomputer 46, which will be described later, is input between the output terminal of the UHF band filter 28 and the input terminal of the second diode D2 via the resistor R2. do.

As shown in FIG. 3, the RF amplifier 32 has its first gate terminal connected in common with the first and second diodes D1 and D2 via a capacitor C1. The gate terminal is connected between the resistor R5 and the capacitor C2 to receive an AGC (Automatic Gain Control) voltage for gain control of the input signal, and the source terminal of the power supply (B +) via the resistor R7. And a drain terminal includes a field effect transistor 48 connected to an input terminal of the VHF inter-terminal tuning section 34 and the UHF inter-step tuning section 36 via a capacitor C4.

Further, reference numeral 34 denotes a VHF which is subjected to high frequency amplification by the RF amplifier 32 by receiving inductance capacity from receiving channel tuning data VT1 for tuning a predetermined channel of the VHF band from the microcomputer 46, which will be described later. A VHF inter-step tuning unit for tuning an RF signal of a desired channel from an RF signal of a band is shown. 36 denotes a capacitance capacity by receiving channel tuning data VT2 for tuning a predetermined channel of a UHF band from a microcomputer 46, which will be described later. The UHF inter-step tuning unit for tuning the RF signal of the desired channel from the RF signal of the UHF band, which has been changed and amplified by the RF amplifier 32, is shown.

Reference numeral 38 denotes a local oscillation unit for generating a predetermined local oscillation frequency signal by the channel channeling data VT1 and VT2, and 40 denotes a VHF from the local oscillation frequency signal and the VHF stage interlocking unit 34. A signal mixing section for generating an intermediate frequency signal of 58.75 MHz by mixing with the RF signal of the band or the UHF RF signal from the UHF inter-step tuning section 36.

Reference numeral 42 denotes a function setting section including a 10-key and a channel short selection key for key operation for tuning of a predetermined channel, consisting of a matrix button provided in a predetermined portion of a remote controller for remote control or a main body of the control panel.

Reference numeral 44 denotes a channel data memory in which channel tuning data for tuning a plurality of broadcast channels in the VHF band and the UHF band is stored, and 46 denotes a microcomputer that controls the overall functional operation of the television. The microcomputer 46 selects 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 the predetermined channel selected by the function setting section 42. In addition to generating a channel selection voltage VT2 for channel selection in the UHF band, the switching unit 30 generates switching control signals SC1 and SC2 in which mutual signal levels are inverted corresponding to the channel selection state. Done.

In this case, when the microcomputer 46 selects a broadcasting channel of the VHF band, the microcomputer 46 makes the switching control signal SC1 a low level signal and makes the switching control signal SC2 a high level signal, while broadcasting the UHF band. When the channel is tuned, the switching control signal SC1 is a high level signal and the switching control signal SC2 is a low level signal.

Next, the operation of the present invention made as described above will be described in detail with reference to the accompanying drawings.

First, in the case where a broadcasting channel of the VHF band is selected 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 tuning data VT1 for tuning the broadcast channel of the VHF band is generated by the channel tuning data of the channel data memory 44, and the low level switching control signal SC1 and the high level switching control signal ( SC2) will be generated respectively.

In this state, the RF signal in which only the high frequency signal is filtered by the high frequency filter 24 and only the VHF band is filtered through the VHF band filter 26 is passed through the first diode D1 of the switch unit 30. It is applied to the first gate terminal of the field effect transistor 48 of the RF amplifier 32, the AGC voltage is applied to the field effect transistor 48, the gain of the input voltage is controlled by the second gate terminal While outputting a high frequency amplified RF signal of the VHF band through the drain terminal, while the VHF inter-terminal tuning unit 34 is applied to the channel selection voltage (VT1) from the microcomputer 46, a change in inductance capacity occurs. While the RF signal of the desired channel is tuned from the RF signal of the VHF band from the RF amplifier 32, the signal mixing unit 40 locally oscillates the RF signal of the tuned channel 38. Intermediate frequency signal mixed with frequency signal It is generated.

On the other hand, in the case where the channel selection of the UHF band is made by the function setting unit 42, the microcomputer 46 selects the channel selection voltage for the channel selection of the UHF band by the channel data of the channel data memory 44. VT2) is generated, and a high level switching control signal SC1 and a low level switching control signal SC2 are generated.

Accordingly, the switch unit 30 receives the RF signal filtered through the high frequency filter 24 and only the UHF band is filtered by the UHF band filter 28 through the second diode D2. It is input to the first gate terminal of the field effect transistor 48 provided in the single RF amplifier 32, and the RF of the UHF band is amplified and output through the drain terminal of the field effect transistor 48 In the signal, the RF signal of the desired channel is tuned by the UHF stage interlocking unit 36 according to the channel tuning voltage VT2, and the tuned RF signal is tuned by the signal mixing unit 40 to the local oscillator 38. It is mixed with the local oscillation frequency signal from and output as an intermediate frequency signal.

According to the present invention made as described above, the RF signal according to the tuning channel of the VHF rental and the RF signal according to the tuning channel of the UHF band in the tuner of the television to operate a high frequency amplification in common through a single RF amplifier circuit Accordingly, the circuit configuration inside the tuner is 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 by the reception antenna 22; A VHF band filter 26 for filtering and passing only the VHF band in 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; 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 by receiving the selective switching control signals SC1 and SC2 by the stations of the VHF band and the UHF band. Switch unit 30 to selectively pass through, Single RF amplification unit 32 receives the RF signal of the VHF band and the RF signal of the UHF band that has passed through the switch unit 30 by a high frequency amplification operation in common by the gain control of the AGC voltage, VHF inter-step tuning for tuning the RF signal of the corresponding channel in the RF signal according to the VHF band amplified by the single RF amplifier 32 by receiving the channel tuning voltage VT1 for tuning a predetermined channel of the VHF band. Part 34, UHF single phase tuning for tuning an RF signal of a corresponding channel in an RF signal according to a UHF band amplified by the single RF amplifier 32 by receiving a channel tuning voltage VT2 for tuning a predetermined channel of a UHF band. Part 36, A signal mixer 40 for mixing a local oscillation frequency signal generated from a local oscillator 38 and an RF signal tuned by the VHF inter-terminal tuning unit 34 or the UHF inter-terminal tuning unit 36 to generate an intermediate frequency signal; and , The channel tuning voltage VT1 for channel presetting in the VHF band or the channel tuning voltage VT2 for tuning the predetermined channel in the UHF band is generated by the channel tuning data stored in the channel data memory 44. The microcomputer (34) or the UHF stage interlocking unit (36), which generates switching control signals (SC1, SC2) to the switch unit (30) in response to the channel tuning state of the VHF band or the UHF band. 46) RF amplification sharing apparatus for a television tuner, comprising: a television tuner. The microcomputer 46 of claim 1, wherein the switch unit 30 is inputted through the resistor R1 between the first diode D1 terminal connected forward to the output terminal of the VHF band filter 26. Whether to supply the RF signal according to the VHF band is determined according to the signal level of the switching control signal (SC1) from), and the second diode (D2) terminal forward connected to the output terminal of the UHF band filter 28 is determined. RF of a television tuner, characterized in that the supply of the RF signal according to the UHF band is determined according to the signal level of the switching control signal SC2 from the microcomputer 46 inputted through the resistor R2. Amplification common device.