CN1340963A - TV tuning component - Google Patents
TV tuning component Download PDFInfo
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- CN1340963A CN1340963A CN01123746A CN01123746A CN1340963A CN 1340963 A CN1340963 A CN 1340963A CN 01123746 A CN01123746 A CN 01123746A CN 01123746 A CN01123746 A CN 01123746A CN 1340963 A CN1340963 A CN 1340963A
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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)
- Superheterodyne Receivers (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (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.
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 switched voltage S2 at its negative electrode place.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 implements frequency translation to TV signal, the frequency-modulation broadcasting signal is implemented the blender that frequency translation is used under the sound signal intermediate frequency in described midband, dispose switching diode, and can be according to when described switching diode is in blocking state, being positioned in the middle of the cardinal principle of described midband, the mode that is positioned at described sound signal intermediate frequency when being in conducting state is implemented the intermediate frequency resonant tank of switching to tuned frequency, dispose variable capacitance diode, and can implement to switch to the reverse bias voltage that is applied on the described variable capacitance diode according to the diadic voltage that varies in size, to contrast the high frequency of described midband or to implement the trap-wave loop of decay usefulness to being positioned at the middle substantially frequency of locating of described midband, and can be used at least the low-frequency band of vhf band and the band decoder device of high frequency band enforcement selection, and 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 being provided with the described frequency band of input selects voltage and by the output of second terminal 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, when described TV signal is implemented the signal reception, switched voltage by described second terminal output can make described switching diode be in blocking state, and the switched voltage of being exported by described the 3rd terminal can make the reverse bias voltage that is applied to described variable capacitance diode place bigger, when described fm broadcast signal is implemented the signal reception, switched voltage by described second terminal output can make described switching diode be in conducting state, and can make the reverse bias voltage that is applied to described variable capacitance diode place smaller by the switched voltage of described the 3rd terminal output.
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, low-potential voltage as switched voltage is lower than the current potential of described first supply voltage, makes by the output of described the 3rd terminal, all the current potential than described first supply voltage is low as the high-potential voltage of switched voltage and low-potential voltage.
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 the first transistor, positive pole-negative pole-positive pole (PNP) type transistor seconds and negative pole-positive pole-negative pole (NPN) type the 3rd transistor constitute, collector electrode on the described the first transistor is connected with described second terminal, and be applied with second source voltage, base stage place on described the first transistor is applied with described frequency band and selects voltage, emitter on the described the first transistor is connected with earth point, collector electrode on the described transistor seconds is connected with described the 3rd terminal, emitter place on described transistor seconds is applied with described first supply voltage, base stage on the described transistor seconds is connected with collector electrode on described the 3rd transistor, base stage place on described the 3rd transistor is applied with described frequency band and selects voltage, and the emitter on described the 3rd 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, low-potential voltage as switched voltage is lower than first supply voltage, make by the 3rd terminal output, high-potential voltage and low-potential voltage as switched voltage are all low than first supply voltage, 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 the first transistor, positive pole-negative pole-positive pole (PNP) type transistor seconds and negative pole-positive pole-negative pole (NPN) type the 3rd 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.
Specific implementation method
Below with reference to Fig. 1 and Fig. 2, to a kind of visual tuning group constructed according to the invention Part describes. Fig. 1 uses for expression a kind of tv tuning component constructed according to the invention Schematic block diagram, Fig. 2 uses tv tuning component as shown in Figure 1 for expression In the schematic loop diagram used of intermediate frequency resonant tank, trap-wave loop and switching circuit.
As shown in Figure 1, this tv tuning component can have very high frequency(VHF) loop section 2, very high frequency(VHF) is mixed with frequency with loop section 4, hyperfrequency with frequency mixer 3, hyperfrequency Close device 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 to being positioned at very high frequency(VHF) Implement the occasion that signal receives, TV with the TV signal in the frequency band or fm broadcast signal Signal or fm broadcast signal can be transformed to intermediate frequency with frequency mixer 3 by very high frequency(VHF) Signal. For implementing the field that signal receives to being positioned at hyperfrequency with the TV signal of frequency band Close, 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 section 2, and is connected by series connection successively Very high frequency(VHF) is then used High frequency amplification loop 13 and very high with a day line loop 12, very high frequency(VHF) Frequently consist of with resonant tank 14. Here, very high frequency(VHF) is a kind of generals with a day line loop 12 Input to the very high frequency(VHF) high frequency as the signal that receives signal in the high-frequency signal of importing The loop that amplifying return circuit 13 places use, very high frequency(VHF) are a kind of to institute with High frequency amplification loop 13 The high-frequency signal of input implements to amplify the loop of usefulness, and very high frequency(VHF) is one with resonant tank 14 Plant the loop that the signal of importing is implemented tuning processing usefulness.
Receive for the TV signal enforcement signal of using low-frequency band to being arranged in very high frequency(VHF) Occasion can be imported very high frequency(VHF)s to very high frequency(VHF) with day line loop 12 by band decoder device 10 Select voltage VL with low-frequency band, thereby can be positioned at day 12 pairs of line loops by very high frequency(VHF) The very high frequency(VHF) of 54 megahertzes～88 megahertzes is implemented tuning with the TV signal in the low-frequency band Process. For TV signal or the fm broadcast signal of using high frequency band to being arranged in very high frequency(VHF) Implement the occasion that signal receives, can be returned with antenna to very high frequency(VHF) by band decoder device 10 Road 12 input very high frequency(VHF)s are selected voltage VH with high frequency band, thereby can be by the very high frequency(VHF) sky 12 pairs of line loops are arranged in the very high frequency(VHF) high frequency band of 174 megahertzes～216 megahertzes TV signal, or the frequency modulation that is arranged in 89 megahertzes～173 megahertz frequency bands is wide Broadcast signal and implement tuning processing.
For real with TV signal or the fm broadcast signal of frequency band to being arranged in very high frequency(VHF) Execute the occasion that signal receives, can be by band decoder device 10 to the very high frequency(VHF) High frequency amplification Loop 13 input very high frequency(VHF)s select voltage VL or very high frequency(VHF) to select with high frequency band with low-frequency band Select voltage VH, thereby very high frequency(VHF) is moved with High frequency amplification loop 13. For this Plant occasion, because band decoder device 10 is not imported with High frequency amplification loop 17 to hyperfrequency Hyperfrequency is selected voltage U with frequency band, so hyperfrequency is not transported with High frequency amplification loop 17 OK.
Receive for the TV signal enforcement signal of using low-frequency band to being arranged in very high frequency(VHF) Occasion can be imported very high frequency(VHF)s to very high frequency(VHF) with resonant tank 14 by band decoder device 10 Select voltage VL with low-frequency band, thereby can be positioned at 14 pairs of resonant tanks by very high frequency(VHF) The very high frequency(VHF) of 54 megahertzes～88 megahertzes is implemented tuning with the TV signal in the low-frequency band Process. For TV signal or the fm broadcast signal of using high frequency band to being arranged in very high frequency(VHF) Implement the occasion that signal receives, can be by band decoder device 10 to very high frequency(VHF) with tuning time Road 14 input very high frequency(VHF)s are selected voltage VH with high frequency band, thereby can be by very high frequency(VHF) with transferring 14 pairs in humorous loop is arranged in the very high frequency(VHF) high frequency band of 174 megahertzes～216 megahertzes TV signal, or the frequency modulation that is arranged in 89 megahertzes～173 megahertz frequency bands is wide Broadcast signal and implement tuning processing.
14 that provide with resonant tank by very high frequency(VHF), be positioned at 54 megahertzes～216 megahertzes Hereby the TV signal of very high frequency(VHF) in the frequency band, or be positioned at 89 megahertzes～173 megahertzes Hereby the fm broadcast signal in the frequency band, and by very high frequency(VHF) oscillation signals according generator 15 oscillation signals according that provide all input to very high frequency(VHF) frequency mixer 3. Very high Frequently use the frequency of oscillation of oscillation signals according generator 15, can be with the interior phaselocked loop that is equipped with The variation of the VT TU that the band decoder device 10 in loop, road provides and change institute When receiving to implement signal when the TV signal of using frequency band to being arranged in very high frequency(VHF), can make Its output likens the local oscillation letter into high 44 megahertzes of TV signal that receive signal to Number, when the frequency-modulation broadcasting signal is implemented signal and is received, can make again its output liken to into Receive the oscillation signals according of high 41.25 megahertzes of fm broadcast signal of signal. Cause This, being arranged in very high frequency(VHF) can be at the intermediate frequency that is 44 megahertzes with the TV signal of frequency band Implement frequency transformation under the signal, fm broadcast signal can with as in the TV signal Implement frequently under the sound if signal of 41.25 megahertzes that the sound if signal frequency is suitable The rate conversion.
Hyperfrequency is connected in parallel with loop section 2 with very high frequency(VHF) with loop section 4, and with the sky Line component 1 is connected, and this hyperfrequency can be by being connected in series successively with loop section 4 The hyperfrequency of a day line loop 16, hyperfrequency High frequency amplification loop 17 and hyperfrequency Consist of with resonant tank 18. Here, hyperfrequency is a kind of passable with a day line loop 16 With TV letter needed in the high-frequency signal of importing, that be arranged in hyperfrequency usefulness frequency band Number export the loop that hyperfrequency is used with 17 places, High frequency amplification loop, hyperfrequency high frequency to Amplifying return circuit 17 is a kind of loop that the high-frequency signal of importing is implemented amplification usefulness, and is super High frequency is a kind of the signal of importing to be implemented returning of tuning processing usefulness with resonant tank 18 The road.
For implementing the field that signal receives to being positioned at hyperfrequency with the TV signal of frequency band Close, can be by hyperfrequency with a day line loop 16, to being positioned at 470 megahertzes～890 megahertzes Hereby hyperfrequency is implemented tuning processing with the TV signal in the frequency band.
And, can be defeated with High frequency amplification loop 17 to hyperfrequency by band decoder device 10 Enter hyperfrequency and select voltage U with frequency band, thereby make hyperfrequency use High frequency amplification loop 17 Operation. For this occasion, because band decoder device 10 is not put with high frequency to very high frequency(VHF) Big loop 13 input very high frequency(VHF)s are selected voltage VL and very high frequency(VHF) high frequency band with low-frequency band Select voltage VH, so very high frequency(VHF) is not implemented operation with High frequency amplification loop 13.
And, can be positioned at hyperfrequency with frequency band with 18 pairs of resonant tanks by hyperfrequency TV signal is implemented tuning processing.
18 that provide with resonant tank by hyperfrequency, be positioned at 470 megahertzes～890,000,000 The hyperfrequency of the hertz TV signal of frequency band, and by the hyperfrequency oscillation signals according The oscillation signals according that generator 19 provides all inputs to the hyperfrequency frequency mixer 5. Hyperfrequency can be equipped with interior with the frequency of oscillation of oscillation signals according generator 19 The variation of the VT TU that the band decoder device 10 in phase-locked loop loop provides and becoming Change, so the TV signal frequency that its output is likened to receiving signal is high by 44,000,000 The oscillation signals according of hertz. Therefore, being arranged in hyperfrequency can with the TV signal of frequency band Under the intermediate-freuqncy signal of 44 megahertzes, to implement frequency transformation.
Implement overfrequency with frequency mixer 3 or hyperfrequency with frequency mixer 5 by very high frequency(VHF) The TV signal of rate conversion or fm broadcast signal are implemented tuning by intermediate frequency resonant tank 6 Process. Intermediate frequency resonant tank 6 is a kind of balanced type loop as shown in Figure 2, and tool First capacitor 25 and the first inductor 26a, 26b that connection parallel with one another is arranged, switch Diode 20, and the one end is connected and phase with negative electrode on the switching diode 20 Second capacitor 27 that is being connected in parallel mutually and second inductor 28. Size is 5 volts (V) The first supply voltage B1 be applied between the first inductor 26a, the 26b and locate, and logical Cross the first inductor 26a and apply first supply voltage to the anode on the switching diode 20 B1.
Intermediate frequency resonant tank 6 also is connected with switching circuit 11, on the switching diode 20 Negative electrode be connected with second terminal 23 on the switching circuit 11. Switching circuit 11 is A kind of integrated loop, its equivalent circuit include first switching transistor 31, the Two switching transistors, 32, the three switching transistors, 33, the first resistors, 34, the second electricity Resistance device 35, the three resistors 36 and the 4th resistor 37. First switching transistor 31 Be a kind of negative pole-positive pole-negative pole (NPN) transistor npn npn, its emitter stage links to each other with earth point Connect, base stage is by the first terminal 22 on first resistor 34 and the band decoder device 10 Be connected, colelctor electrode is connected with earth point by second resistor 35, and with Two-terminal 23 is connected. Second switch transistor 32 is a kind of positive pole-negative pole-positive poles (PNP) transistor npn npn, its colelctor 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 applies At its emitter stage place, its base stage links to each other with colelctor electrode on the 3rd switching transistor 33 Connect. The 3rd switching transistor 33 is a kind of negative pole-positive pole-negative pole (NPN) transistor npn npns, Its colelctor electrode is connected emitter stage and ground connection with base stage on first switching transistor 31 Point is connected, and base stage is by the first end on the 4th resistor 37 and the band decoder device 10 Son 22 is connected. Therefore, when two to switching circuit 11 inputs by band decoder device 10 When the value frequency band is selected voltage S, second terminal 23 and the 3rd terminal on the switching circuit 11 24 will export respectively the switched voltage of diadic.
When TV signal is implemented the signal reception, the first end on the band decoder device 10 Son 22 will be 0 volt frequency band selection voltage S to switching circuit 11 output sizes. At this The time, first switching transistor 31 is in blocking state, and size is 30 volts second source Voltage B2 will implement dividing potential drop by second resistor 35 and the 5th resistor 38, thereby make The voltage that is applied to second terminal, 23 places is 10 volts, so that can be to switching diode 20 On to apply size be 10 volts switched voltage at the negative electrode place. Therefore, because at switch two What utmost point pipe 20 places applied is the bias voltage that is reverse direction, makes it be in the blocking-up shape Attitude is so intermediate frequency resonant tank 6 can pass through first capacitor 25 and first inductor 26a, 26b implement tuning processing in parallel. For this occasion, tuned frequency is 44,000,000 Hertz, frequency bandwidth is 6 megahertzes.
When the frequency-modulation broadcasting signal is implemented signal and is received, the on the band decoder device 10 One terminal 22 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, the electricity at second terminal, 23 places Pressure is 0 volt, is 0 so can apply size to the negative electrode place on the switching diode 20 The switched voltage of volt. Therefore, be to be forward owing to what apply at switching diode 20 places The bias voltage of direction makes it be in conducting state, so intermediate frequency resonant tank 6 can By first capacitor 25, the first inductor 26a, 26b, second capacitor 27 and Two inductors 28 are implemented tuning processing in parallel. For this occasion, tuned frequency is 41.25 Megahertz, frequency bandwidth are 1.5 megahertzes.
By TV signal or the fm broadcast signal after the intermediate frequency resonant tank 6, input To trap-wave loop 7. Trap-wave loop 7 can be by the varactor that is connecting parallel with one another 21, the 3rd capacitor 29 and the 3rd inductor 30 consist of, and are inserted in parallel loop In a loop in. Size is 5 volts the first supply voltage B1, by first electricity Sensor 26a is applied to the negative electrode place on the varactor 21.
For TV signal is implemented the occasion that signal receives, can be by band decoder device 10 On the first terminal 22 be 0 volt frequency band selection voltage to switching circuit 11 output sizes S makes the 3rd switching transistor 33 be in blocking state, and makes the second switch transistor 32 are in blocking state. At this moment, the voltage that is applied to the 3rd terminal 24 places is 0 volt, The reverse bias voltage that is applied to varactor 21 places is 5 volts, so transfiguration two utmost points The capacitance of pipe 21 is smaller. For this state, implement decay by trap-wave loop 7 Signal frequency, be the frequency higher than midband frequency, be as and adjacent TV frequently 47.25 megahertzes of the midband frequency that the sound carrier frequency in road is corresponding.
Implement the occasion that signal receives for the frequency-modulation broadcasting signal, can be by band decoder The first terminal 22 on the device 10 is 5 volts frequency band choosing to switching circuit 11 output sizes Select voltage S. At this moment, the 3rd switching transistor 33 is in conducting state, and the Two switching transistors 32 also are in conducting state. By the 3rd terminal 24 that export, sizes The voltage that is 5 volts is implemented dividing potential drop by the 6th resistor 39 and the 7th resistor 40, thereby Can the anode place on varactor 21 apply size and be 4 volts switched voltage, The reverse bias voltage that applies at varactor 21 places is 1 volt, therefore can make change The capacitance of holding diode 21 is bigger. For this state, real by trap-wave loop 7 Execute the signal frequency of decay, for substantially being positioned at 43 megahertzes of locating in the middle of the midband.
By TV signal or the fm broadcast signal after the trap-wave loop 7, in inputing to Frequently amplifying return circuit 8 is processed to implement to amplify. After being implemented to amplify by intermediate frequency amplifying return circuit 8 TV signal or fm broadcast signal input to sawtooth waveforms mode filter 9. The sawtooth wave mode The transmission band of wave filter 9 is 41 megahertz to 47 megahertzes, so TV signal Midband can pass through. And the transmission band ratio of sawtooth waveforms mode filter 9 is at audio frequency The frequency band of the fm broadcast signal under the signal intermediate frequency after the enforcement frequency transformation is wider, so right Implement the occasion that signal receives in the frequency-modulation broadcasting signal, can utilize the intermediate frequency resonant tank 6, trap-wave loop 7, to the signal adjacent with the fm broadcast signal of conduct reception signal Implement to remove, thus can be only by the frequency band of tv tuning component output as the reception signal Signal.
Claims (4)
1. tv tuning component is characterized in that having 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 blender that frequency translation is used,
Dispose switching diode and according in the middle of the cardinal principle that when described switching diode is in blocking state, is positioned at described midband, the mode that is positioned at described sound signal intermediate frequency when being in conducting state implements the intermediate frequency resonant tank that switches to tuned frequency,
Dispose variable capacitance diode and according to the diadic voltage that varies in size implement to switch to being applied to reverse bias voltage on the described variable capacitance diode, with contrast the high frequency of described midband or to be positioned at described midband substantially in the middle of the frequency at place implement the trap-wave loop of decay usefulness
And be used at least the low-frequency band of vhf band and the band decoder device of high frequency band enforcement selection,
And 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 being provided with the described frequency band of input selects voltage and by the output of second terminal described switching diode is switched to diadic switched voltage that conducting state or blocking state use, implements to switch the switching circuit of 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
When described TV signal is implemented the signal reception, switched voltage by described second terminal output makes described switching diode be in blocking state, switched voltage by described the 3rd terminal output makes the reverse bias voltage that is applied to described variable capacitance diode place bigger simultaneously
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 makes the reverse bias voltage that is applied to described variable capacitance diode place smaller by the switched voltage of described the 3rd terminal output.
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 as the low-potential voltage of switched voltage than the current potential of described first supply voltage,
By the output of described the 3rd terminal, all the current potential than described first supply voltage is low as the high-potential voltage of switched voltage and low-potential voltage.
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 the first transistor, positive pole-negative pole-positive-type transistor seconds and negative pole-positive pole-negative-type the 3rd transistor,
Collector electrode on the described the first transistor is connected with described second terminal, and is applied with second source voltage,
Base stage place on described the first transistor is applied with described frequency band and selects voltage,
Emitter on the described the first transistor is connected with earth point,
Collector electrode on the described transistor seconds is connected with described the 3rd terminal,
Emitter place on described transistor seconds is applied with described first supply voltage,
Base stage on the described transistor seconds is connected with collector electrode on described the 3rd transistor,
Base stage place on described the 3rd transistor is applied with described frequency band and selects voltage,
Emitter on described the 3rd 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 true CN1340963A (en) | 2002-03-20 |
| CN1179554C 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) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102263915A (en) * | 2010-05-25 | 2011-11-30 | 阿尔卑斯电气株式会社 | input tuning circuit of television tuner |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002359788A (en) | 2001-05-31 | 2002-12-13 | Alps Electric Co Ltd | Television receiver |
-
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
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102263915A (en) * | 2010-05-25 | 2011-11-30 | 阿尔卑斯电气株式会社 | input tuning circuit of television tuner |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20020015655A (en) | 2002-02-28 |
| JP3765974B2 (en) | 2006-04-12 |
| CN1179554C (en) | 2004-12-08 |
| KR100397112B1 (en) | 2003-09-06 |
| JP2002064757A (en) | 2002-02-28 |
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