CN1179554C - TV tuning component - Google Patents
TV tuning component Download PDFInfo
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- CN1179554C CN1179554C CNB011237465A CN01123746A CN1179554C CN 1179554 C CN1179554 C CN 1179554C CN B011237465 A CNB011237465 A CN B011237465A CN 01123746 A CN01123746 A CN 01123746A CN 1179554 C CN1179554 C CN 1179554C
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- switching
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/41—Structure of client; Structure of client peripherals
- H04N21/426—Internal components of the client ; Characteristics thereof
- H04N21/42607—Internal components of the client ; Characteristics thereof for processing the incoming bitstream
- H04N21/4263—Internal components of the client ; Characteristics thereof for processing the incoming bitstream involving specific tuning arrangements, e.g. two tuners
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
- H03J5/24—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with a number of separate pretuned tuning circuits or separate tuning elements selectively brought into circuit, e.g. for waveband selection or for television channel selection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/50—Tuning indicators; Automatic tuning control
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Superheterodyne Receivers (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
- Television Receiver Circuits (AREA)
Abstract
The invention aims to provide an inexpensive television tuner by controlling a tuning frequency of a tuning circuit and a trap frequency of a trap circuit with a signal from a band decoder, so as to simplify the circuitry of the band decoder. A changeover circuit 11 receives a binary band selection voltage from the band decoder 10, a switching voltage outputted from a 2nd terminal 23 changes a tuning frequency of an intermediate frequency tuning circuit 6, a switching voltage outputted from a 3rd terminal 24 changes a trap frequency of a trap circuit 7.
Description
Technical field
The present invention relates to be used for TV signal is implemented the tv tuning component that signal receives, particularly can also broadcast signal and implement the TV signal reception tuning block that signal receives frequency modulation program (FM).
Background technology
Below with reference to Fig. 3 and Fig. 4, a kind of tv tuning component of the prior art is described.Tv tuning component as shown in Figure 3 is by very high frequency(VHF) (VHF) loop portion 52, very high frequency(VHF) frequency mixer 53, hyperfrequency (UHF) loop portion 54, hyperfrequency frequency mixer 55, intermediate frequency resonant tank 56, trap-wave loop 57, intermediate frequency amplifying return circuit 58, sawtooth wave mode (SAW) filter 59 and band decoder device 60 constitute.For implementing the occasion that signal receives to being arranged in very high frequency(VHF) with the TV signal or the fm broadcast signal of frequency band, TV signal or fm broadcast signal are transformed to intermediate-freuqncy signal by very high frequency(VHF) with frequency mixer 53.For implementing the occasion that signal receives to being positioned at hyperfrequency with the TV signal of frequency band, TV signal is transformed to intermediate-freuqncy signal by hyperfrequency with frequency mixer 55.
Very high frequency(VHF) is connected with antenna module 51 with loop portion 52, and is made of with resonant tank 63 with high frequency amplifying return circuit 62 and very high frequency(VHF) with antenna loop 61, very high frequency(VHF) the very high frequency(VHF) that is being connected in series.Here, very high frequency(VHF) is a kind ofly signal as received signal in the high-frequency signal of being imported can be inputed to the loop that very high frequency(VHF) is used with high frequency amplifying return circuit 62 places with antenna loop 61, very high frequency(VHF) is a kind of loops that the high-frequency signal of being imported is implemented amplification usefulness with high frequency amplifying return circuit 62, and very high frequency(VHF) is a kind of loops of the signal of being imported being implemented tuning processing usefulness with resonant tank 63.
63 that provide with resonant tank by very high frequency(VHF), as to be arranged in 54 megahertzes (MHz)～216 megahertz very high frequency(VHF) is with the TV signal of frequency band, or be arranged in the fm broadcast signal of 89 megahertzes～173 megahertz frequency bands, and, all input to very high frequency(VHF) frequency mixer 53 by the oscillation signals according that very high frequency(VHF) provides with oscillation signals according generator 64.The very high frequency(VHF) frequency of oscillation of oscillation signals according generator 64, the variation of the tuning voltage TU that can provide with the interior band decoder device 60 that phase-locked loop (PLL) loop is housed changes, so when the TV signal that is arranged in very high frequency(VHF) usefulness frequency band is implemented the signal reception, can make its output liken oscillation signals according to into high 44 megahertzes of TV signal of received signal, when the frequency-modulation broadcasting signal is implemented signal and received, can make its output liken oscillation signals according to again into high 41.25 megahertzes of fm broadcast signal of received signal.Therefore, be arranged in very high frequency(VHF) and can under the intermediate-freuqncy signal that is 44 megahertzes, implement frequency translation with the TV signal of frequency band, fm broadcast signal can with sound if signal as 41.25 suitable megahertzes of the sound if signal frequency in the TV signal under implement frequency translation.
Hyperfrequency is connected in parallel with loop portion 52 with very high frequency(VHF) with loop portion 54, and be connected with antenna module 51, and this hyperfrequency can be made of with resonant tank 67 with high frequency amplifying return circuit 66 and hyperfrequency with antenna loop 65, hyperfrequency the hyperfrequency that is being connected in series with loop portion 54.Here, hyperfrequency is with the operational mode in each loop in the portion 54 of loop, and is similar with the operational mode in each loop in the loop portion 52 with corresponding very high frequency(VHF), so omitted the detailed description to them.
54 that provide with resonant tank by hyperfrequency, as to be arranged in 470 megahertzes～890 megahertzes hyperfrequency is with the TV signal of frequency band, and, all input to hyperfrequency frequency mixer 55 by the oscillation signals according that hyperfrequency provides with oscillation signals according generator 68.The hyperfrequency frequency of oscillation of oscillation signals according generator 68, the variation of the tuning voltage TU that can provide with the interior band decoder device 60 that the phase-locked loop loop is housed changes, so can export the oscillation signals according that likens to high 44 megahertzes of TV signal frequency of received signal.Therefore, be positioned at hyperfrequency and can under the intermediate-freuqncy signal that is 44 megahertzes, implement frequency translation with the TV signal of frequency band.
Use frequency mixer 55 to implement the TV signal or the fm broadcast signal of overfrequency conversion by very high frequency(VHF) with frequency mixer 53 or hyperfrequency, implement tuning processing by intermediate frequency resonant tank 56.Intermediate frequency resonant tank 56 can be as shown in Figure 4, has variable capacitance diode 69, the one end is connected with anode on the variable capacitance diode 69 and first capacitor 70 that the other end is connected with earth point, and the first inductor 71a, the 71b of one end high frequency earthing, and the first inductor 71a, 71b are connected in parallel with respect to the loop that is connected in series that is made of the variable capacitance diode 69 and first capacitor 70, thereby constitute a kind of resonant tank in parallel.Frequency band selects voltage S1 to be applied to tie point place between the first inductor 71a, the 71b, and this voltage also is supplied to negative electrode place on the variable capacitance diode 69 by the first inductor 71a.Anode on the variable capacitance diode 69 is connected with earth point by resistor 72.The negative electrode that is positioned on the variable capacitance diode 69 is connected with the output end on the frequency mixer 53 with very high frequency(VHF) with tie point between the first inductor 71a, and is connected with trap-wave loop 57.
For TV signal is implemented the occasion that signal receives, select voltage S1 by band decoder device 60 frequency bands output, that be positioned at high potential, to be applied to negative electrode place on the variable capacitance diode 69 by the first inductor 71a, thereby be applied with reverse bias voltage at variable capacitance diode 69 places.At this moment, the inductance value of the capacitance of the capacitance of variable capacitance diode 69, first capacitor 70 and the first inductor 71a, 71b is being determined the tuned frequency of intermediate frequency resonant tank 56, is 44 megahertzes thereby can make this tuned frequency.When the frequency-modulation broadcasting signal is implemented the signal reception, select voltage S1 by band decoder device 60 frequency bands output, that be positioned at electronegative potential, to be applied to negative electrode place on the variable capacitance diode 69 by the first inductor 71a, thereby make the anode on the variable capacitance diode 69 be in identical current potential place substantially with negative electrode.At this moment, the capacitance of variable capacitance diode 69 is very big, so tuned frequency can be lowered, is 41.25 megahertzes thereby can make tuned frequency at this moment.
Implement tuning processing TV signal or fm broadcast signal afterwards by intermediate frequency resonant tank 56, input to trap-wave loop 57.Trap-wave loop 57 is made of second inductor 73, second capacitor 74 and the switching diode 75 that is connecting parallel with one another.Anode place on switching diode 75 is applying supply voltage+B, is applying frequency band at its negative electrode place and is selecting voltage S2.For TV signal is implemented the occasion that signal receives, the frequency band that is applied to negative electrode place on the switching diode 75 by band decoder device 60 selects voltage S2 to be in electronegative potential, so can make switching diode 75 be in conducting state, the signal that is positioned at any frequency not implemented attenuation processing.Implement the occasion that signal receives for the frequency-modulation broadcasting signal, the frequency band that is applied to negative electrode place on the switching diode 75 by band decoder device 60 selects voltage S2 to be positioned at high potential, so by the signal frequency of trap-wave loop 57 enforcement attenuation processing, for being positioned at 43 middle megahertzes of midband substantially.
Implement tuning processing TV signal or fm broadcast signal afterwards by intermediate frequency resonant tank 56, input to intermediate frequency amplifying return circuit 58 to implement processing and amplifying.TV signal or fm broadcast signal by after the 58 enforcement amplifications of intermediate frequency amplifying return circuit input to sawtooth waveforms mode filter 59.The transmission band of sawtooth waveforms mode filter 59 is 41 megahertz to 47 megahertzes, and therefore the midband as TV signal can pass through.And, the transmission band of sawtooth waveforms mode filter 59 is wideer than the frequency band of the fm broadcast signal after implementing frequency translation under the sound signal intermediate frequency, so implement the occasion that signal receives for the frequency-modulation broadcasting signal, can utilize intermediate frequency resonant tank 56, trap-wave loop 57, to with implement to remove as the adjacent signal of the fm broadcast signal of received signal, thereby can be only by the band signal of tv tuning component output as received signal.
Yet, this tv tuning component of the prior art is to TV signal or the reception of fm broadcast signal enforcement signal the time, must select voltage to intermediate frequency resonant tank and trap-wave loop output band by the band decoder device, so need make each frequency band select the current potential of high-potential voltage in the voltage to differ from one another.Therefore, the loop of band decoder device constitutes more complicated, and is difficult to realize low-cost.
Summary of the invention
The present invention is exactly the invention that addresses the above problem usefulness, purpose of the present invention just provides a kind of frequency band that is provided by the band decoder device that can utilize and selects voltage, trap frequency to tuning alignment of tuned circuit frequency and trap-wave loop is implemented control, thereby can make the loop form of the composition of band decoder device simple, and then can realize the tv tuning component of cost degradation.
In order to address the above problem, a kind of tv tuning component provided by the present invention can have under the TV midband TV signal being implemented under frequency translation, the sound signal intermediate frequency in described midband the frequency-modulation broadcasting signal implements the frequency mixer that frequency translation is used, dispose intermediate frequency resonant tank switching diode, that enforcement is switched to tuned frequency, wherein, when described switching diode is in blocking state, adopt the frequency that is positioned at place, described TV midband centre position as tuned frequency; When described switching diode is in conducting state, employing is positioned at the frequency of described sound signal intermediate frequency as tuned frequency, dispose variable capacitance diode, to contrast the high frequency of described midband or to implement the trap-wave loop of decay usefulness to being positioned at the frequency of locating in described midband centre position, and can be used for the low-frequency band of vhf band and the band decoder device of high frequency band enforcement selection, wherein be provided with the first terminal that diadic frequency band that output selects described TV signal or described fm broadcast signal to use selects voltage to use at described band decoder device place, and be provided with the switching circuit that the described frequency band of input is selected voltage, switching circuit is provided with second terminal and the 3rd terminal, by second terminal output described switching diode is switched to the diadic switched voltage that conducting state or blocking state are used, implement to switch the switching circuit of the diadic switched voltage of usefulness by the 3rd terminal output to being applied to reverse bias voltage on the described variable capacitance diode, described trap-wave loop is implemented to switch to the reverse bias voltage that is applied on the described variable capacitance diode according to the diadic switched voltage of described the 3rd terminal output, when described TV signal is implemented the signal reception, switched voltage by described second terminal output makes described switching diode be in blocking state, when the switched voltage of being exported by described the 3rd terminal makes the reverse bias voltage ratio that is applied to described variable capacitance diode place receive fm broadcast signal simultaneously, reverse bias voltage height on the described variable capacitance diode, when described fm broadcast signal is implemented the signal reception, switched voltage by described second terminal output makes described switching diode be in conducting state, and making the reverse bias voltage that is applied to described variable capacitance diode place during than received television signal by the switched voltage of described the 3rd terminal output, the reverse biased electrical on the described variable capacitance diode is forced down.
And, a kind of tv tuning component constructed according to the invention, further the anode place on described switching diode is applied with first supply voltage, and its negative electrode is connected with described second terminal, negative electrode place on described variable capacitance diode is applied with described first supply voltage, and its anode is connected with described the 3rd terminal, and can make by the output of described second terminal, as the high-potential voltage of switched voltage current potential height than described first supply voltage, the low-potential voltage as switched voltage by the output of described second terminal is lower than the current potential of described first supply voltage, makes by described the 3rd terminal output, equate with the current potential of described first supply voltage or lower as the high-potential voltage of switched voltage and low-potential voltage than it.
And, a kind of tv tuning component constructed according to the invention, can also further make described switching circuit by negative pole-positive pole-negative pole (NPN) type first switching transistor, positive pole-negative pole-positive pole (PNP) type second switch transistor and negative pole-positive pole-negative pole (NPN) type the 3rd switching transistor constitute, collector electrode on described first switching transistor is connected with described second terminal, and be applied with second source voltage, base stage place on described first switching transistor is applied with described frequency band and selects voltage, emitter on described first switching transistor is connected with earth point, collector electrode on the described second switch transistor is connected with described the 3rd terminal, emitter place on described second switch transistor is applied with described first supply voltage, base stage on the described second switch transistor is connected with collector electrode on described the 3rd switching transistor, base stage place on described the 3rd switching transistor is applied with described frequency band and selects voltage, and the emitter on described the 3rd switching transistor is connected with earth point.
And, a kind of tv tuning component constructed according to the invention, can also further make described switching circuit is a kind of loop of integrated circuit form.
As mentioned above, tv tuning component constructed according to the invention, be a kind of can be when TV signal and fm broadcast signal be implemented to receive, change the tv tuning component of the trap frequency of intermediate frequency alignment of tuned circuit frequency and trap-wave loop, this tv tuning component can be respectively applied for the switched voltage of the trap frequency of intermediate frequency alignment of tuned circuit frequency and trap-wave loop being implemented switching by switching circuit output, so can utilize by the band decoder device and select voltage to a frequency band of switching circuit output, the trap frequency of intermediate frequency alignment of tuned circuit frequency and trap-wave loop is implemented to switch, therefore can reduce the lead-out terminal number on the band decoder device, simplify the loop form of the composition of band decoder device, and then realize cost degradation.
And, the switching circuit of use in tv tuning component constructed according to the invention, can make by second terminal output, as the high-potential voltage of switched voltage than the first supply voltage height, export by described second terminal, low-potential voltage as switched voltage is lower than first supply voltage, make by the 3rd terminal output, equate with the current potential of described first supply voltage or lower as the high-potential voltage of switched voltage and low-potential voltage than it, therefore can utilize suitable voltage, respectively to changing the variable capacitance diode enforcement control that intermediate frequency alignment of tuned circuit frequency switching diode of using and the trap frequency that changes trap-wave loop are used.
And, the switching circuit of use in tv tuning component constructed according to the invention, can constitute by negative pole-positive pole-negative pole (NPN) type first switching transistor, positive pole-negative pole-positive pole (PNP) type second switch transistor and negative pole-positive pole-negative pole (NPN) type the 3rd switching transistor, therefore be a kind of switching circuit that is made of fewer element, this can make its further miniaturization.
And tv tuning component constructed according to the invention can also be by the further miniaturization of mode of integrated circuit.
Description of drawings
The schematic block diagram that Fig. 1 uses for expression a kind of tv tuning component constructed according to the invention.
The schematic loop diagram that Fig. 2 uses intermediate frequency resonant tank, trap-wave loop and switching circuit in this tv tuning component constructed according to the invention to use for expression.
The schematic block diagram that Fig. 3 uses for expression a kind of tv tuning component of the prior art.
The schematic loop diagram that Fig. 4 uses intermediate frequency resonant tank in the prior art a kind of tv tuning component and trap-wave loop to use for expression.
Embodiment
Below with reference to Fig. 1 and Fig. 2, a kind of tv tuning component constructed according to the invention is described.The schematic block diagram that Fig. 1 uses for expression a kind of tv tuning component constructed according to the invention, the schematic loop diagram that Fig. 2 uses intermediate frequency resonant tank, trap-wave loop and switching circuit in tv tuning component as shown in Figure 1 to use for expression.
As shown in Figure 1, this tv tuning component can have very high frequency(VHF) loop portion 2, very high frequency(VHF) frequency mixer 3, hyperfrequency loop portion 4, hyperfrequency frequency mixer 5, intermediate frequency resonant tank 6, trap-wave loop 7, intermediate frequency amplifying return circuit 8, sawtooth waveforms mode filter 9, band decoder device 10 and switching circuit 11.For implementing the occasion that signal receives to being arranged in very high frequency(VHF) with the TV signal or the fm broadcast signal of frequency band, TV signal or fm broadcast signal can be transformed to intermediate-freuqncy signal with frequency mixer 3 by very high frequency(VHF).For implementing the occasion that signal receives to being positioned at hyperfrequency with the TV signal of frequency band, TV signal can be transformed to intermediate-freuqncy signal with frequency mixer 5 by hyperfrequency.
Very high frequency(VHF) is connected with antenna module 1 with loop portion 2, and is made of with resonant tank 14 with high frequency amplifying return circuit 13 and very high frequency(VHF) with antenna loop 12, very high frequency(VHF) the very high frequency(VHF) that is being connected in series successively.Here, very high frequency(VHF) is a kind of signal as received signal in the high-frequency signal of being imported to be inputed to the loop that very high frequency(VHF) is used with high frequency amplifying return circuit 13 places with antenna loop 12, very high frequency(VHF) is a kind of loops that the high-frequency signal of being imported is implemented amplification usefulness with high frequency amplifying return circuit 13, and very high frequency(VHF) is a kind of loops of the signal of being imported being implemented tuning processing usefulness with resonant tank 14.
For implementing the occasion that signal receives with the TV signal of low-frequency band to being arranged in very high frequency(VHF), can select voltage VL with antenna loop 12 input very high frequency(VHF)s with low-frequency band to very high frequency(VHF) by band decoder device 10, thereby can implement tuning processing with the very high frequency(VHF) that 12 pairs of antenna loops are arranged in 54 megahertzes～88 megahertzes with the TV signal of low-frequency band by very high frequency(VHF).For implementing the occasion that signal receives with the TV signal or the fm broadcast signal of high frequency band to being arranged in very high frequency(VHF), can select voltage VH with antenna loop 12 input very high frequency(VHF)s with high frequency band to very high frequency(VHF) by band decoder device 10, thereby can be arranged in the TV signal of the very high frequency(VHF) of 174 megahertzes～216 megahertzes with 12 pairs of antenna loops by very high frequency(VHF), or the fm broadcast signal that is arranged in 89 megahertzes～173 megahertz frequency bands is implemented tuning processing with high frequency band.
For implementing the occasion that signal receives with the TV signal or the fm broadcast signal of frequency band to being arranged in very high frequency(VHF), can select voltage VL or very high frequency(VHF) with high frequency band to select voltage VH with high frequency amplifying return circuit 13 input very high frequency(VHF)s with low-frequency band to very high frequency(VHF) by band decoder device 10, thereby can make very high frequency(VHF) high frequency amplifying return circuit 13 operations.For this occasion, because band decoder device 10 is not selected voltage U with high frequency amplifying return circuit 17 input hyperfrequencies with frequency band to hyperfrequency, so hyperfrequency does not move with high frequency amplifying return circuit 17.
For implementing the occasion that signal receives with the TV signal of low-frequency band to being arranged in very high frequency(VHF), can select voltage VL with resonant tank 14 input very high frequency(VHF)s with low-frequency band to very high frequency(VHF) by band decoder device 10, thereby can implement tuning processing with the very high frequency(VHF) that 14 pairs of resonant tanks are arranged in 54 megahertzes～88 megahertzes with the TV signal of low-frequency band by very high frequency(VHF).For implementing the occasion that signal receives with the TV signal or the fm broadcast signal of high frequency band to being arranged in very high frequency(VHF), can select voltage VH with resonant tank 14 input very high frequency(VHF)s with high frequency band to very high frequency(VHF) by band decoder device 10, thereby can be arranged in the TV signal of the very high frequency(VHF) of 174 megahertzes～216 megahertzes with 14 pairs of resonant tanks by very high frequency(VHF), or the fm broadcast signal that is arranged in 89 megahertzes～173 megahertz frequency bands is implemented tuning processing with high frequency band.
14 that provide with resonant tank by very high frequency(VHF), as to be arranged in 54 megahertzes～216 megahertzes very high frequency(VHF) is with the TV signal of frequency band, or be arranged in the fm broadcast signal of 89 megahertzes～173 megahertz frequency bands, and, all input to very high frequency(VHF) frequency mixer 3 by the oscillation signals according that very high frequency(VHF) provides with oscillation signals according generator 15.The very high frequency(VHF) frequency of oscillation of oscillation signals according generator 15, the variation of the tuning voltage TU that can provide with the interior band decoder device 10 that the phase-locked loop loop is housed changes, so when the TV signal that is arranged in very high frequency(VHF) usefulness frequency band is implemented the signal reception, can make its output liken oscillation signals according to into high 44 megahertzes of TV signal of received signal, when the frequency-modulation broadcasting signal is implemented signal and received, can make its output liken oscillation signals according to again into high 41.25 megahertzes of fm broadcast signal of received signal.Therefore, be arranged in very high frequency(VHF) and can under the intermediate-freuqncy signal that is 44 megahertzes, implement frequency translation with the TV signal of frequency band, fm broadcast signal can with sound if signal as 41.25 suitable megahertzes of the sound if signal frequency in the TV signal under implement frequency translation.
Hyperfrequency is connected in parallel with loop portion 2 with very high frequency(VHF) with loop portion 4, and be connected with antenna module 1, and this hyperfrequency can be made of with resonant tank 18 with high frequency amplifying return circuit 17 and hyperfrequency with antenna loop 16, hyperfrequency the hyperfrequency that is being connected in series successively with loop portion 4.Here, hyperfrequency with antenna loop 16 be a kind of can with needed in the high-frequency signal of being imported, be arranged in hyperfrequency and export the loop that hyperfrequency is used with high frequency amplifying return circuit 17 places to the TV signal of frequency band, hyperfrequency is a kind of loops that the high-frequency signal of being imported is implemented amplification usefulness with high frequency amplifying return circuit 17, and hyperfrequency is a kind of loops of the signal of being imported being implemented tuning processing usefulness with resonant tank 18.
For implementing the occasion that signal receives with the TV signal of frequency band, can implement tuning processing to the hyperfrequency that is arranged in 470 megahertzes～890 megahertzes with the TV signal of frequency band by hyperfrequency with antenna loop 16 to being positioned at hyperfrequency.
And, can select voltage U with high frequency amplifying return circuit 17 input hyperfrequencies with frequency band to hyperfrequency by band decoder device 10, thereby hyperfrequency is moved with high frequency amplifying return circuit 17.For this occasion, because band decoder device 10 does not select voltage VL and very high frequency(VHF) with high frequency band to select voltage VH with high frequency amplifying return circuit 13 input very high frequency(VHF)s with low-frequency band to very high frequency(VHF), so very high frequency(VHF) is not implemented operation with high frequency amplifying return circuit 13.
And, can be positioned at hyperfrequency with 18 pairs of resonant tanks by hyperfrequency and implement tuning processing with the TV signal of frequency band.
18 that provide with resonant tank by hyperfrequency, as to be positioned at 470 megahertzes～890 megahertzes hyperfrequency is with the TV signal of frequency band, and by the oscillation signals according that hyperfrequency provides with oscillation signals according generator 19, all inputs to hyperfrequency usefulness frequency mixer 5.The hyperfrequency frequency of oscillation of oscillation signals according generator 19, the variation of the tuning voltage TU that can provide with the interior band decoder device 10 that the phase-locked loop loop is housed changes, so can make its output liken oscillation signals according into high 44 megahertzes of TV signal frequency of received signal to.Therefore, be arranged in hyperfrequency and can under the intermediate-freuqncy signal that is 44 megahertzes, implement frequency translation with the TV signal of frequency band.
Use frequency mixer 5 to implement the TV signal or the fm broadcast signal of overfrequency conversion by very high frequency(VHF) with frequency mixer 3 or hyperfrequency, implement tuning processing by intermediate frequency resonant tank 6.Intermediate frequency resonant tank 6 as shown in Figure 2, it is a kind of balanced type loop, and first capacitor 25 and the first inductor 26a, 26b with connection parallel with one another, switching diode 20, and the one end is connected and second capacitor 27 that is being connected parallel with one another and second inductor 28 with negative electrode on the switching diode 20.Size is that the first supply voltage B1 of 5 volts (V) is applied between the first inductor 26a, the 26b and locates, and applies the first supply voltage B1 by the anode of the first inductor 26a on switching diode 20.
Intermediate frequency resonant tank 6 also is connected with switching circuit 11, and the negative electrode on the switching diode 20 is connected with second terminal 23 on the switching circuit 11.Switching circuit 11 is a kind of integrated loops, and its equivalent circuit includes first switching transistor 31, second switch transistor 32, the three switching transistors 33, the first resistor 34, the second resistors, 35, the three resistors 36 and the 4th resistors 37.First switching transistor 31 is a kind of negative pole-positive pole-negative pole (NPN) type switching transistors, its emitter is connected with earth point, base stage is connected with the first terminal 22 on the band decoder device 10 by first resistor 34, collector electrode is connected with earth point by second resistor 35, and is connected with second terminal 23.Second switch transistor 32 is a kind of positive pole-negative pole-positive pole (PNP) type switching transistors, its collector electrode is connected with earth point by the 3rd resistor 36, and be connected with the 3rd terminal 24, size is that 5 volts the first supply voltage B1 is applied to its emitter place, and its base stage is connected with collector electrode on the 3rd switching transistor 33.The 3rd switching transistor 33 is a kind of negative pole-positive pole-negative pole (NPN) type switching transistors, its collector electrode is connected with base stage on first switching transistor 31, emitter is connected with earth point, and base stage is connected with the first terminal 22 on the band decoder device 10 by the 4th resistor 37.Therefore, when by band decoder device 10 when switching circuit 11 input diadic frequency bands are selected voltage S, second terminal 23 and the 3rd terminal 24 on the switching circuit 11 will be exported the switched voltage of diadic respectively.
When TV signal is implemented the signal reception, the first terminal 22 on the band decoder device 10 will be 0 volt frequency band selection voltage S to switching circuit 11 output sizes.At this moment, first switching transistor 31 is in blocking state, size is that 30 volts second source voltage B2 will implement dividing potential drop by second resistor 35 and the 5th resistor 38, thereby making the voltage that is applied to second terminal, 23 places is 10 volts, is 10 volts switched voltage so that can apply size to the negative electrode place on the switching diode 20.Therefore, be the bias voltage that is reverse direction owing to what apply at switching diode 20 places, make it be in blocking state, so intermediate frequency resonant tank 6 can be implemented tuning processing in parallel by first capacitor 25 and the first inductor 26a, 26b.For this occasion, tuned frequency is 44 megahertzes, and frequency bandwidth is 6 megahertzes.
When the frequency-modulation broadcasting signal is implemented the signal reception, the first terminal 22 on the band decoder device 10 will be 5 volts frequency band selection voltage S to switching circuit 11 output sizes.At this moment, first switching transistor 31 is in conducting state, and the voltage at second terminal, 23 places is 0 volt, is 0 volt switched voltage so can apply size to the negative electrode place on the switching diode 20.Therefore, because what apply at switching diode 20 places is the bias voltage that is direction, make it be in conducting state, implement tuning processing in parallel so intermediate frequency resonant tank 6 can pass through first capacitor 25, the first inductor 26a, 26b, second capacitor 27 and second inductor 28.For this occasion, tuned frequency is 41.25 megahertzes, and frequency bandwidth is 1.5 megahertzes.
TV signal or fm broadcast signal by after the intermediate frequency resonant tank 6 input to trap-wave loop 7.Trap-wave loop 7 can be made of the variable capacitance diode that is connecting 21 parallel with one another, the 3rd capacitor 29 and the 3rd inductor 30, and is inserted in the loop in the parallel circuits.Size is 5 volts the first supply voltage B1, is applied to negative electrode place on the variable capacitance diode 21 by the first inductor 26a.
For TV signal is implemented the occasion that signal receives, can be 0 volt frequency band selection voltage S by the first terminal on the band decoder device 10 22 to switching circuit 11 output sizes, make the 3rd switching transistor 33 be in blocking state, and make second switch transistor 32 be in blocking state.At this moment, the voltage that is applied to the 3rd terminal 24 places is 0 volt, and the reverse bias voltage that is applied to variable capacitance diode 21 places is 5 volts, so the capacitance of variable capacitance diode 21 is smaller.For this state, implement the signal frequency of decay by trap-wave loop 7, be the frequency higher than midband frequency, be as with 47.25 megahertzes of the corresponding midband frequency of sound carrier frequency of adjacent television channel.
Implementing the occasion that signal receives for the frequency-modulation broadcasting signal, can be 5 volts frequency band selection voltage S by the first terminal on the band decoder device 10 22 to switching circuit 11 output sizes.At this moment, the 3rd switching transistor 33 is in conducting state, and second switch transistor 32 also is in conducting state.By the output of the 3rd terminal 24, size is that 5 volts voltage is by the 6th resistor 39 and the 7th resistor 40 enforcement dividing potential drops, thereby can apply size at the anode place on the variable capacitance diode 21 and be 4 volts switched voltage, the reverse bias voltage that applies at variable capacitance diode 21 places is 1 volt, therefore can make the capacitance of variable capacitance diode 21 bigger.For this state, by the signal frequency of trap-wave loop 7 enforcement decay, for being positioned at 43 megahertzes of locating in the middle of the midband substantially.
By TV signal or the fm broadcast signal after the trap-wave loop 7, input to intermediate frequency amplifying return circuit 8 to implement processing and amplifying.TV signal or fm broadcast signal by after the 8 enforcement amplifications of intermediate frequency amplifying return circuit input to sawtooth waveforms mode filter 9.The transmission band of sawtooth waveforms mode filter 9 is 41 megahertz to 47 megahertzes, so the midband of TV signal can pass through.And, the transmission band of sawtooth waveforms mode filter 9 is wideer than the frequency band of the fm broadcast signal after implementing frequency translation under the sound signal intermediate frequency, so implement the occasion that signal receives for the frequency-modulation broadcasting signal, can utilize intermediate frequency resonant tank 6, trap-wave loop 7, to with implement to remove as the adjacent signal of the fm broadcast signal of received signal, thereby can be only by the band signal of tv tuning component output as received signal.
Claims (4)
1. tv tuning component has under the TV midband TV signal being implemented under frequency translation, the sound signal intermediate frequency in described midband the frequency-modulation broadcasting signal and implements the frequency mixer that frequency translation is used,
Dispose intermediate frequency resonant tank switching diode, that enforcement is switched to tuned frequency, wherein, when described switching diode is in blocking state, adopt the frequency that is positioned at place, described TV midband centre position as tuned frequency; When described switching diode is in conducting state, adopt the frequency that is positioned at described sound signal intermediate frequency as tuned frequency,
Dispose variable capacitance diode, contrasting the high frequency of described midband or the frequency that is positioned at described midband centre position place implemented the trap-wave loop of decay usefulness,
And be used for the low-frequency band of vhf band and the band decoder device of high frequency band enforcement selection,
It is characterized in that being provided with the first terminal that diadic frequency band that output selects described TV signal or described fm broadcast signal to use selects voltage to use at described band decoder device place,
And be provided with the switching circuit that the described frequency band of input is selected voltage, switching circuit is provided with second terminal and the 3rd terminal, by second terminal output described switching diode is switched to diadic switched voltage that conducting state or blocking state use, implements to switch the diadic switched voltage of usefulness by the output of the 3rd terminal to being applied to reverse bias voltage on the described variable capacitance diode
Described trap-wave loop is implemented to switch to the reverse bias voltage that is applied on the described variable capacitance diode according to the diadic switched voltage of described the 3rd terminal output,
When described TV signal is implemented the signal reception, switched voltage by described second terminal output makes described switching diode be in blocking state, when the switched voltage of being exported by described the 3rd terminal makes the reverse bias voltage ratio that is applied to described variable capacitance diode place receive fm broadcast signal simultaneously, reverse bias voltage height on the described variable capacitance diode
When described fm broadcast signal is implemented the signal reception, switched voltage by described second terminal output makes described switching diode be in conducting state, and making the reverse bias voltage that is applied to described variable capacitance diode place during than received television signal by the switched voltage of described the 3rd terminal output, the reverse biased electrical on the described variable capacitance diode is forced down.
2. tv tuning component as claimed in claim 1 is characterized in that the anode place on described switching diode is applied with first supply voltage, and its negative electrode is connected with described second terminal simultaneously,
Negative electrode place on described variable capacitance diode is applied with described first supply voltage, and its anode is connected with described the 3rd terminal simultaneously,
By the output of described second terminal, as the high-potential voltage of switched voltage current potential height than described first supply voltage, lower by the low-potential voltage as switched voltage of described second terminal output than the current potential of described first supply voltage,
By the output of described the 3rd terminal, equate with the current potential of described first supply voltage or lower as the high-potential voltage of switched voltage and low-potential voltage than it.
3. tv tuning component as claimed in claim 2 is characterized in that described switching circuit is made of negative pole-positive pole-negative-type first switching transistor, positive pole-negative pole-positive-type second switch transistor and negative pole-positive pole-negative-type the 3rd switching transistor,
Collector electrode on described first switching transistor is connected with described second terminal, and is applied with second source voltage,
Base stage place on described first switching transistor is applied with described frequency band and selects voltage,
Emitter on described first switching transistor is connected with earth point,
Collector electrode on the described second switch transistor is connected with described the 3rd terminal,
Emitter place on described second switch transistor is applied with described first supply voltage,
Base stage on the described second switch transistor is connected with collector electrode on described the 3rd switching transistor,
Base stage place on described the 3rd switching transistor is applied with described frequency band and selects voltage,
Emitter on described the 3rd switching transistor is connected with earth point.
4. tv tuning component as claimed in claim 3 is characterized in that described switching circuit is a kind of loop of integrated circuit form.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000255746A JP3765974B2 (en) | 2000-08-22 | 2000-08-22 | Television tuner |
| JP255746/2000 | 2000-08-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1340963A CN1340963A (en) | 2002-03-20 |
| CN1179554C true CN1179554C (en) | 2004-12-08 |
Family
ID=18744478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB011237465A Expired - Fee Related CN1179554C (en) | 2000-08-22 | 2001-07-31 | TV tuning component |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3765974B2 (en) |
| KR (1) | KR100397112B1 (en) |
| CN (1) | CN1179554C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002359788A (en) | 2001-05-31 | 2002-12-13 | Alps Electric Co Ltd | Television receiver |
| JP2011249982A (en) * | 2010-05-25 | 2011-12-08 | Alps Electric Co Ltd | Input tuning circuit for television tuner |
-
2000
- 2000-08-22 JP JP2000255746A patent/JP3765974B2/en not_active Expired - Fee Related
-
2001
- 2001-07-31 CN CNB011237465A patent/CN1179554C/en not_active Expired - Fee Related
- 2001-08-21 KR KR10-2001-0050218A patent/KR100397112B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JP3765974B2 (en) | 2006-04-12 |
| JP2002064757A (en) | 2002-02-28 |
| KR100397112B1 (en) | 2003-09-06 |
| KR20020015655A (en) | 2002-02-28 |
| CN1340963A (en) | 2002-03-20 |
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