CN1249915C - TV signal switching circuit - Google Patents
TV signal switching circuit Download PDFInfo
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- CN1249915C CN1249915C CN 200310119744 CN200310119744A CN1249915C CN 1249915 C CN1249915 C CN 1249915C CN 200310119744 CN200310119744 CN 200310119744 CN 200310119744 A CN200310119744 A CN 200310119744A CN 1249915 C CN1249915 C CN 1249915C
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Abstract
Provided is a television signal switching circuit which is simplified by reducing the number of components and in which a consumption current is reduced. This television signal switching circuit is provided with a high frequency amplifier circuit 1 provided between the input port 3 of a television signal and an input tuning circuit 11, a diode 4 which is provided in parallel with the high frequency amplifier circuit 1 and bypasses the television signal, wherein bias voltage is applied to the anode of the diode 4. The circuit is provided with a first switching means 2 for switching operations of the high frequency amplifier circuit 1 and a second switching means 6 that is turned on/off conversely from the first switching means 2. A power supply voltage is applied to the high frequency amplifier circuit 1 through the first switching means 2, and the cathode of the diode 4 is grounded by the second switching means 6.
Description
Technical field
The present invention relates to the TV signal commutation circuit, relate in particular on the input part that is arranged on TV tuner, the TV signal commutation circuit of switching when the input of the highfield of TV signal and during the weak electric field input.
Background technology
Fig. 2 combines expression to the TV signal commutation circuit in the past and the component part of TV tuner.High-frequency amplifier circuit 31 has field-effect transistor (FET) 31a as amplifier element, source electrode high frequency ground ground connection, and drain electrode is connected with power supply terminal B with resistance by inductance.And grid connect the anode of the 1st switching diode 32.The anode of the grid of FET31a and the 1st switching diode 32 is connected on the collector electrode of the PNP transistor 34 that switches usefulness by bias resistance 33.The emitter of PNP transistor 34 is connected on the power supply terminal B.The negative electrode of the 1st switching diode 32 is by bias resistance 35 ground connection, and with input 36 couplings of TV signal.
And, on the anode of the drain coupled to the of FET31a 2 switching diodes 37.The anode of the 2nd switching diode 37 is connected on the collector electrode of PNP transistor 34 by bias resistance 38.Moreover the negative electrode of the 2nd switching diode 37 passes through bias resistance 39 ground connection, and is coupled on the VHF input tuning circuit 40a and UHF input tuning circuit 40b of TV tuner 40.
Shunting is arranged between the negative electrode of the negative electrode of the 1st switching diode 32 and the 2nd switching diode 37 with diode 41, and anode is connected on the power supply terminal B by bias resistance 42.Then, the anode of diode 41 is connected on the negative electrode of the 1st switching diode 32, and negative electrode is connected on the negative electrode of the 2nd switching diode 37.
In above structure, when the TV signal of input is weak electric field, on the base stage of PNP transistor 34, add low level switched voltage.So, 34 conductings of PNP transistor, 32,37 conductings of the 1st and the 2nd switching diode simultaneously, add supply voltage on high-frequency amplifier circuit 31, form operating state.At this moment, set the voltage on the negative electrode of the 2nd switching diode 37 with 4 bias resistances 33,35,38,39, make the voltage on its negative electrode that is higher than the 1st switching diode 32, so shunting ends with diode 41.So the TV signal of input is amplified by high-frequency amplifier circuit 31, be input to then in VHF input tuning circuit 40a and the UHF input tuning circuit 40b.
On the other hand, when TV signal is highfield, on the base stage of PNP transistor 34, add the switched voltage of high level.So PNP transistor 34 ends, the 1st and the 2nd switching diode 32,37 ends.Simultaneously, on high-frequency amplifier circuit 31, do not add power supply voltage, so, non operating state become.But, because shunting is with passing through bias resistance 39,42 inflow currents on the diode 41, so become conducting.So the TV signal of input is not amplified by high-frequency amplifier circuit 31, but be imported into (for example with reference to patent documentation 1) in VHF input tuning circuit 40a and the UHF input tuning circuit 40b by diode 41.
[patent documentation 1]: the spy opens the 2002-261501 communique.
In said structure, the problem of existence is: when making high-frequency amplifier circuit work, the switching diode that is arranged on its input side carries out conducting with the switching diode that is arranged on outlet side, so the quantity of switching diode increases, and current drain increases.And, at this moment, utilize the bias voltage of the negative electrode of each switching diode to make shunting be in cut-off state with diode, so, need four bias resistances to be used for setting above-mentioned bias voltage, these resistance values are set very miscellaneous.
Summary of the invention
The object of the present invention is to provide and a kind ofly can reduce number of spare parts and simplify circuit, and reduce the TV signal commutation circuit of current sinking.
TV signal commutation circuit of the present invention has: high-frequency amplifier circuit is arranged between the input and input tuning circuit of TV signal; And shunting diode, be arranged in parallel with above-mentioned high-frequency amplifier circuit, be used for above-mentioned TV signal is shunted, be provided with: the 1st switching device, be used at above-mentioned shunting biasing on the anode of diode, and the action of above-mentioned high-frequency amplifier circuit is switched; And the 2nd switching device, carry out on/off according to the direction opposite with above-mentioned the 1st switching device.And, respectively with the 1st and the 2PNP transistor constitute the above-mentioned first and the 2nd switching device, above-mentioned supply voltage is added on the transistorized emitter of above-mentioned 1PNP, the transistorized collector electrode of above-mentioned 1PNP is connected on the power supply supply side of above-mentioned high-frequency amplifier circuit, the transistorized emitter of above-mentioned 2PNP is connected to above-mentioned shunting with on the negative electrode of diode; And, collector electrode is carried out ground connection, be connected to base stage on the transistorized collector electrode of above-mentioned 1PNP and DC earthing, switched voltage is added on the transistorized base stage of above-mentioned 1PNP.By above-mentioned the 1st switching device supply voltage is added on the above-mentioned high-frequency amplifier circuit, utilizes above-mentioned the 2nd switching device that above-mentioned shunting is carried out ground connection with the negative electrode of diode.
Moreover above-mentioned high-frequency amplifier circuit has amplifier element, by the bias resistance of using to the input terminal supply bias voltage of above-mentioned amplifier element the transistorized base stage of above-mentioned 2PNP is carried out DC earthing.
And, above-mentioned input tuning circuit has: the tuning switching with inductance element and tuning frequency band used switching diode, supply with bias voltage from supply voltage to above-mentioned switching diode by above-mentioned inductance element, the anode of above-mentioned shunting with diode is connected with above-mentioned inductance element direct current.
The invention effect
As mentioned above, according to the present invention, have: high-frequency amplifier circuit is arranged between the input and input tuning circuit of TV signal; And shunting diode, be arranged in parallel with above-mentioned high-frequency amplifier circuit, be used for above-mentioned TV signal is shunted, be provided with: the 1st switching device, be used at above-mentioned shunting biasing on the anode of diode, and the action of above-mentioned high-frequency amplifier circuit is switched; And the 2nd switching device, carry out on/off according to the direction opposite with above-mentioned the 1st switching device.By above-mentioned the 1st switching device supply voltage is added on the above-mentioned high-frequency amplifier circuit, utilizes above-mentioned the 2nd switching device that above-mentioned shunting is carried out ground connection with the negative electrode of diode.So can realize the TV signal commutation circuit with simple formation.
And, respectively with the 1st and the 2PNP transistor constitute the above-mentioned first and the 2nd switching device, above-mentioned supply voltage is added on the transistorized emitter of above-mentioned 1PNP, the transistorized collector electrode of above-mentioned 1PNP is connected on the power supply supply side of above-mentioned high-frequency amplifier circuit, the transistorized emitter of above-mentioned 2PNP is connected to above-mentioned shunting with on the negative electrode of diode; And, with grounded collector, be connected to base stage on the transistorized collector electrode of above-mentioned 1PNP and DC earthing, switched voltage is added on the transistorized base stage of above-mentioned 1PNP.So can make the 1st switching device and the 2nd switching device oppositely carry out on/off.
Moreover above-mentioned high-frequency amplifier circuit has amplifier element, by the bias resistance of using to the input terminal supply bias voltage of above-mentioned amplifier element the transistorized base stage of above-mentioned 2PNP is carried out DC earthing.So, even special-purpose bias circuit is not set on the transistorized base stage of 2PNP, also can the 1PNP transistor become by the time, make the 2PNP transistor become conducting.
And, going up above-mentioned input tuning circuit has: the tuning switching with inductance element and tuning frequency band used switching diode, supply with bias voltage from supply voltage to above-mentioned switching diode by above-mentioned inductance element, the anode of above-mentioned shunting with diode is connected with above-mentioned inductance element direct current.So, supply with bias voltage to shunting with the anode of diode from input tuning circuit, therefore, do not need to be used for biased special-purpose bias circuit.
Description of drawings
Fig. 1 is the circuit diagram of expression TV signal commutation circuit structure of the present invention.
Fig. 2 is the circuit diagram of the existing TV signal commutation circuit structure of expression.
Embodiment
Fig. 1 represents the TV signal commutation circuit structure of inventing, and represents with the local component part of TV tuner.High-frequency amplifier circuit 1 has the transistor 1a as amplifier element, and emitter high frequency ground ground connection is connected on the collector electrode as the 1PNP transistor 2 of the 1st switching device by inductance element 1b as the collector electrode of lead-out terminal.The emitter of 1PNP transistor 2 is connected on the power supply terminal B.And collector electrode is connected on the input 10a of TV tuner 10.And, to base stage as input terminal, utilize its with collector electrode between the 1st bias resistance 1c that is connected and with ground connection between the 2nd bias resistance 1d that is connected supply with bias voltage.And the input 3 of base stage and TV signal is coupled.
The shunting that is used for that TV signal is shunted is coupling in diode 4 between the input 10a of input 3 and TV tuner 10, and anode carries out direct current with input 10a and is connected.And negative electrode is connected on the emitter as the 2PNP transistor 6 of the 2nd switching device by resistance 5.The grounded collector of 2PNP transistor 6, base stage is connected on the collector electrode of 1PNP transistor 2.
In TV tuner 10, have: the VHF amplifying circuit 12 of VHF input tuning circuit 11 and the UHF input tuning circuit 13 that is connected with its input 10a, the next stage that is arranged on VHF input tuning circuit 11 and the UHF amplifying circuit 14 etc. that is arranged on the next stage of UHF input tuning circuit 13.
VHF input tuning circuit 11 has: four inductance element 11a～11d that are connected in series, the variable capacitance diode 11e that is connected in parallel with it, the tuning frequency band that two inductance element 11b, 11c of centre is carried out short circuit at two ends switch the switching diode 11f of usefulness etc.And, utilize voltage to carry out the resistance 11g of dividing potential drop and the bias voltage that 11h forms to power supply terminal B, supply to by inductance element 11a～11c on the anode of switching diode 11f.The tie point of middle two inductance element 11b, 11c is connected on the input 10a.Utilize this structure also on the anode of shunting, to supply with bias voltage with diode 4.
And the negative electrode of switching diode 11f is connected on the switched voltage terminal Vs, and the negative electrode of variable capacitance diode 11e is connected on the tuning voltage terminal Vt.The plus earth of variable capacitance diode 11e.
Then, VHF input tuning circuit 11 switches like this: utilize the switched voltage Vs of high level that switching diode 11f is become and end, carry out tuning in the low-frequency band of VHF band; Utilize low level switched voltage Vs to make switching diode 11f become conducting, on the high frequency band of VHF band, carry out tuning.
In above structure, when the TV signal of input was weak electric field, low level switched voltage was added on the base stage of 1PNP transistor 2.So 2PNP transistor 2 becomes conducting, power supply voltage supplying to the collector electrode of transistor 1a, and, on base stage, also add bias voltage, high-frequency amplifier circuit 1 becomes operating state.And 2PNP transistor 6 becomes and ends, and like this, shunting also becomes with diode 4 and ends.Like this, the TV signal of input is amplified by high-frequency amplifier circuit 1, is input in VHF input tuning circuit 11 and the UHF input tuning circuit 13.
On the other hand, when TV signal was highfield, the switched voltage of high level was added on the base stage of 1PNP transistor 2.So 1PNP transistor 2 becomes and ends.Not to transistor 1a supply line voltage, so high-frequency amplifier circuit 1 becomes non operating state.
But, use on the anode of diode 4 in shunting, inductance element 11a, 11b by VHF input tuning circuit 11 supply with bias voltage, the base stage of 2PNP transistor 6 is connected on the ground wire by inductance element 1b, bias resistance 1c, the 1d of high-frequency amplifier circuit 1, so, 2PNP transistor 6 becomes conducting, and like this, shunting becomes conducting with diode 4.Like this, the TV signal of input is not to be amplified by high-frequency amplifier circuit 1, but is input in VHF input tuning circuit 11 and the UHF input tuning circuit 13 by diode 4.
Claims (3)
1, a kind of TV signal commutation circuit is characterized in that,
Have: high-frequency amplifier circuit is arranged between the input and input tuning circuit of TV signal; And shunt and use diode, be arranged in parallel with above-mentioned high-frequency amplifier circuit, be used for above-mentioned TV signal is shunted,
Be provided with: the 1st switching device is used at above-mentioned shunting biasing on the anode of diode, and the action of above-mentioned high-frequency amplifier circuit is switched; And the 2nd switching device, carry out on/off according to the direction opposite with above-mentioned the 1st switching device,
Respectively with the 1st and the 2PNP transistor constitute the above-mentioned first and the 2nd switching device, above-mentioned supply voltage is added on the transistorized emitter of above-mentioned 1PNP, the transistorized collector electrode of above-mentioned 1PNP is connected on the power supply supply side of above-mentioned high-frequency amplifier circuit, the transistorized emitter of above-mentioned 2PNP is connected to above-mentioned shunting with on the negative electrode of diode; And, collector electrode is carried out ground connection, be connected to base stage on the transistorized collector electrode of above-mentioned 1PNP and DC earthing, switched voltage is added on the transistorized base stage of above-mentioned 1PNP,
By above-mentioned the 1st switching device supply voltage is added on the above-mentioned high-frequency amplifier circuit, utilizes above-mentioned the 2nd switching device that above-mentioned shunting is carried out ground connection with the negative electrode of diode.
2, TV signal commutation circuit as claimed in claim 1, it is characterized in that: above-mentioned high-frequency amplifier circuit has amplifier element, by the bias resistance of using to the input terminal supply bias voltage of above-mentioned amplifier element the transistorized base stage of above-mentioned 2PNP is carried out DC earthing.
3, TV signal commutation circuit as claimed in claim 1 or 2, it is characterized in that: above-mentioned input tuning circuit has: the tuning switching with inductance element and tuning frequency band used switching diode, supply with bias voltage from supply voltage to above-mentioned switching diode by above-mentioned inductance element, the anode of above-mentioned shunting with diode is connected with above-mentioned inductance element direct current.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002352955A JP3891926B2 (en) | 2002-12-04 | 2002-12-04 | Television signal switching circuit |
| JP2002352955 | 2002-12-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1505260A CN1505260A (en) | 2004-06-16 |
| CN1249915C true CN1249915C (en) | 2006-04-05 |
Family
ID=32754408
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200310119744 Expired - Fee Related CN1249915C (en) | 2002-12-04 | 2003-12-03 | TV signal switching circuit |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP3891926B2 (en) |
| CN (1) | CN1249915C (en) |
-
2002
- 2002-12-04 JP JP2002352955A patent/JP3891926B2/en not_active Expired - Fee Related
-
2003
- 2003-12-03 CN CN 200310119744 patent/CN1249915C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004187102A (en) | 2004-07-02 |
| JP3891926B2 (en) | 2007-03-14 |
| CN1505260A (en) | 2004-06-16 |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060405 Termination date: 20111203 |