JPH0775410B2 - Integrated electronic tuning tuner - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated electronic tuning tuner such as a television tuner and an audio receiving tuner.

2. Description of the Related Art In recent years, video information devices such as LCD TVs and VTRs, and audio devices such as system component tuners, compact discs and boomboxes are becoming smaller and thinner, and are becoming more multifunctional and diversified. The tuners are required to have the ability to withstand multiple functions, and with the demand for additional functions, tuners that can be commonly used in various devices are inevitably required to be smaller and thinner.

Hereinafter, a conventional integrated electronic tuner will be described with reference to the drawings.

FIG. 3 is a block diagram of a conventional integrated electronic tuning tuner. In FIG. 3, 1 is an antenna input terminal for inputting an antenna input signal, 2 is a high pass filter that passes only the UHF frequency band of the antenna input signal, 3 is a low pass filter that passes only the VHF frequency band of the antenna input signal, and 4 is a low pass filter. This is an intermediate frequency trap that adjusts the intermediate frequency in order to prevent interference due to the intermediate frequency by inputting the output of the filter 3, and the antenna input circuit 5 is configured as described above. 6 is an RF amplifier circuit that amplifies the RF frequency of the output signal of the antenna input circuit 5, 7 is an interstage detuning circuit that inputs the output of the RF amplifier circuit 6, 8 is a local oscillation circuit in the UHF frequency band, and 9 is a VHF frequency The local oscillation circuit of the band, 10 is the output signal of the interstage detuning circuit 7
Mixing circuit that mixes with the signals of the local oscillator circuits 8 and 9 of UHF or VHF, 11 is an intermediate frequency amplifier circuit that amplifies the intermediate frequency signal from the mixing circuit 10, 12 is an output tuning circuit that extracts the necessary frequency signal, and 13 is It is the intermediate frequency output terminal.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional configuration as described above, in terms of interference rejection capability, the frequencies of the UHF frequency band passing through the high pass filter 2 and the VHF frequencies passing through the low pass filter 3 and the intermediate frequency trap 4 The frequency of the band is the RF amplifier circuit 6
Since it is simultaneously input to VHF frequency when receiving UHF, VHF high channel frequency and UHF frequency when receiving VHF low channel, and VHF low channel frequency and UHF frequency when receiving VHF high channel, respectively. Therefore, in the case of a television, there is a problem that a beat is generated on the screen and sufficient performance as a set cannot be obtained. In addition, even if the antenna input terminal 1 is not used for both UHF and VHF and has a different axis from the beginning, the VHF or UHF signal is input to both terminals at the same time when the set is mounted, so the same conditions are applied. , The same problem occurs when using a uniaxial antenna terminal.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an integrated electronic tuning tuner that improves the performance as a tuner by eliminating interference due to interference of frequency signals other than the reception frequency. It is a thing.

Means for Solving the Problems In order to achieve this object, an integrated electronic tuning tuner of the present invention includes an input terminal, a high-pass filter connected to the input terminal for passing a UHF band high-frequency signal, and the high-pass filter. A first electronic switching circuit whose output is connected to one selection terminal, a high-frequency amplifier circuit connected to a common terminal of the first electronic switching circuit, and an output of this high-frequency amplification circuit is one of A mixing circuit, which is supplied to the input and to which the output of the local oscillation circuit is connected to the other input, an intermediate frequency amplifying circuit to which the output of this mixing circuit is connected, and an output of this intermediate frequency amplifying circuit are connected. An output tuning circuit, an output terminal to which an output of the output tuning circuit is connected, a low-pass filter for passing a VHF band high frequency signal connected to the input terminal, and a low pass filter. A second electronic switching circuit in which the output signal of the filter is connected to the other selection terminal of the first electronic switching circuit and the output signal of the low-pass filter is connected to a common terminal; A first trap circuit connected to one selection terminal of the electronic switching circuit for trapping a high channel frequency in the VHF band, and a VHF band low connected to the other selection terminal of the second electronic switching circuit. A second trap circuit for trapping the channel frequency, UHF
When receiving a high-frequency signal in the band, one selection terminal of the first electronic switching circuit is turned on and the other selection terminal is turned off, and when receiving a high-frequency signal in the VHF band, the other of the first electronic switching circuits is received. Of the second electronic switching circuit is turned on and the other selection terminal is turned off at the time of receiving the low channel in the VHF band, and the other selection terminal is turned off, and the selection terminal of the second electronic switching circuit is turned off. When receiving the high channel, the other selection terminal of the second electronic switching circuit is turned on and one selection terminal is turned off.

Operation With the above configuration, at the time of reception in the UHF band, by turning on one selection terminal of the first electronic switching circuit and turning off the other selection terminal, only the UHF band high frequency signal is passed. When receiving a low channel in the VHF band, by turning on one selection terminal of the second electronic switching circuit and turning off the other selection terminal, the VHF band high channel signal is trapped, and the first electronic The signal in the UHF band is cut off by turning off one selection terminal of the dynamic switching circuit. Therefore, only the VHF low channel signal is passed. When receiving a high channel in the VHF band, the other selection terminal of the second electronic switching circuit is turned on to trap the signal of the VHF band low channel and one selection terminal of the first electronic switching circuit. By turning off, the UHF band signal is cut off and only the VHF high channel signal is passed, and only the reception frequency band is input to the RF amplification circuit. That is, interference interference due to interference of frequency signals other than the reception frequency can be eliminated, and beats on the screen can be eliminated in the case of television, for example, and the performance as a tuner can be improved.

Embodiment One embodiment of the present invention will be described below with reference to the drawings. It should be noted that components having the same effects as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a block diagram of an integrated electronic tuner showing an embodiment of the present invention. In FIG. 1, inputting the output signal from the intermediate frequency trap 4,
The low / high switching circuit 14 for switching between the VHF low channel frequency and the VHF high channel frequency, and the VHF signal which is the output signal of the low / high switching circuit 14 and the UHF signal which is the output signal of the high pass filter 2 are input and switched. The antenna input circuit 16 is configured by adding the UHF / VHF switching circuit 15 so that only the signal of VHF low channel frequency, VHF high channel frequency or UHF frequency is input to the RF amplifier circuit 6. There is.

FIG. 2 shows the low / high switching circuit 14 and UHF / VHF of FIG.
6 is a circuit diagram showing a specific example of a switching circuit 15. FIG.

In FIG. 2, the low-high switching circuit 14 receives a voltage from BV via the resistor 17 and a voltage higher than BV from BS via the resistor 18 at the same time when receiving a VHF low channel. When receiving high channels,
A voltage is applied only to BV. Also, when switching the B power supply, V
A voltage is applied only from BL via the resistor 18 when receiving the HF low channel, and from BH only via the resistor 17 when receiving the VHF high channel. The switching diode 19 does not operate during VHF low channel reception in either case, so the combined capacitance of the capacitors 20 and 21 and the coil 22
A series trap is formed by the inductance of, and the frequency f ₀ can be set to the center frequency of the VHF high channel and the image frequency of the low channel. Further, at the time of receiving the VHF high channel, a voltage is applied from BV or BH via the resistor 17, and at this time is applied via the resistor 18. Since BS has a zero potential, when switching the B power source, BL is open only with BH, so that the switching diode 19 is in the ON state and the capacitance of the capacitor 23 is set sufficiently larger than that of the capacitor 20. , The combined capacitance of the capacitors 23 and 21 and the coil 22 form a series trap for the center frequency of the low channel. At this time, since the capacitance of the capacitor 23 is sufficiently large, the combined capacitance of the capacitors 23 and 21 is almost determined by the capacitance of the capacitor 21.
Further, the capacitor 23 is connected to the intermediate frequency trap 4 etc.
The DC cut function is also set so that the BH voltage and the BH voltage are not applied.

In the UHF / VHF switching circuit 15, BV or BL or BH voltage is applied to the switching diode 24 through the resistor 25 so that the switching diode 24 operates only at VHF. In addition, the switching diode 26, via the resistor 27,
The voltage of BU is applied. When receiving VHF, the voltage is supplied from BV or BL to BH via the resistor 25, so the switching diode 24 operates.
The VHF signal is input to the RF amplifier circuit 6, but the BU diode voltage is in the open state, so the switching diode 26 does not operate, and the UHF signal is not input to the RF amplifier circuit 6, and the VHF signal is always input. Only is input to the RF amplifier circuit. Further, when receiving UHF, the voltage of BU is applied through the resistor 27, and since BV or BL to BH are in the open state, the switching diode 26 operates, the switching diode 24 does not operate, and the RF amplifier circuit 6 receives UHF. Only signals will be input. Therefore, the RF amplifier circuit 6
Since only a frequency signal in the same band as the reception channel is always input to the receiver, interference interference due to input frequencies of different reception bands is reduced, and it is clear that the interference elimination capability is improved.

In this way, for example, the image frequency of the interference factor when receiving the low channel of VHF and the VHF of the Japanese channel
The frequency of 6 channels of VHF high channel, which causes the interference of low high interference between the local oscillation frequency when receiving 1 channel of low channel and the video frequency of 6 channels of VHF high channel, is the low high switching circuit.
It is cut off by 14, so its ability to eliminate interference is improved. In addition, when receiving 6 channels of VHF high channel, the frequency of 1 channel of VHF low channel, which causes high / low interference caused by the video frequency of 1 channel, is cut off by the low / high switching circuit. The ability to eliminate jamming is improved. Also, when receiving 10 channels, the UHF 13 channel is a frequency condition that causes interference, but due to the action of the UHF / VHF switching circuit 15,
Since the HF frequency is cut off, the interference rejection capability is improved. As mentioned above, these interference disturbances also depend on the situation of the broadcasting station, but in television broadcasting there are many combinations that interfere because the video signal and the audio signal are on their respective channels. However, compared to the conventional method, a significant improvement effect of the disturbance rejection ability can be obtained.

As described above, according to the present invention, the input terminal, the high-pass filter that passes the UHF band high frequency signal connected to the input terminal, and the output of the high-pass filter is connected to one selection terminal. A first electronic switching circuit and this first
A high frequency amplifier circuit connected to the common terminal of the electronic switching circuit, and a mixing circuit in which the output of this high frequency amplifier circuit is supplied to one input and the output of the local oscillation circuit is connected to the other input, An intermediate frequency amplifier circuit connected to the output of the mixing circuit, an output tuning circuit connected to the output of the intermediate frequency amplifier circuit, an output terminal connected to the output of the output tuning circuit, and the input terminal A low-pass filter for passing the VHF band high frequency signal, and an output signal of the low-pass filter is connected to the other selection terminal of the first electronic switching circuit and an output signal of the low-pass filter is connected to a common terminal. A second electronic switching circuit that is connected to the first electronic switching circuit, and a first trap that traps a high channel frequency in the VHF band connected to one selection terminal of the second electronic switching circuit. A first trap circuit for trapping a low channel frequency in the VHF band connected to the other selection terminal of the second electronic switching circuit, the first trap circuit receiving the high frequency signal in the UHF band. Of the electronic switching circuit is turned on and the other selection terminal is turned off, and when the high frequency signal in the VHF band is received, the other selection terminal of the first electronic switching circuit is turned on and one of the selection terminals is selected. When the terminal is turned off and the VHF band low channel is received, one of the selection terminals of the second electronic switching circuit is turned on and the other selection terminal is turned off, so that VH
When receiving a high channel in the F band, the other selection terminal of the second electronic switching circuit is turned on and one selection terminal is turned off. Therefore, when receiving in the UHF band, the first electronic switching circuit is selected. By turning on one selection terminal of the circuit and turning off the other selection terminal, it is possible to pass only the high frequency signal in the UHF band, and when receiving the low channel in the VHF band, the second electronic switching circuit By turning on one selection terminal and turning off the other selection terminal, a VHF band high channel signal is trapped, and by turning off one selection terminal of the first electronic switching circuit, a UHF band signal is transmitted. By cutting off, only the VHF low channel signal can be passed, and when receiving the VHF band high channel, the other select end of the second electronic switching circuit The by trapping signal in the VHF band low channel by turning on and by turning off one of the selection terminal of the first electronic switching circuit, cut off the signals in the UHF band VHF
Only high-channel signals can be passed, so that only the reception frequency band can be input to the high-frequency amplifier circuit.

Therefore, interference interference due to interference of frequency signals other than the reception frequency can be eliminated, and beats on the screen can be eliminated in the case of, for example, a television and the performance as a tuner can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an integrated electronic tuning tuner showing an embodiment of the present invention, and FIG. 2 is a specific example of a low / high switching circuit and a VHF / UHF switching circuit of the integrated electronic tuning tuner. Circuit diagram,
FIG. 3 is a block diagram of a conventional integrated electronic tuning tuner. 6 ... RF amplification circuit (high frequency amplification circuit), 8 ... UHF local oscillation circuit, 9 ... VHF local oscillation circuit, 10 ... Mixed circuit, 1
1 …… Intermediate frequency amplifier circuit, 12 …… Output tuning circuit, 14 ……
Low / High switching circuit, 15 …… UHF / VHF switching circuit, 16 ……
Antenna input circuit.

Claims (1)

[Claims] 1. An input terminal and a UH connected to this input terminal
A high-pass filter that passes a high-frequency signal in the F band, a first electronic switching circuit whose output is connected to one selection terminal, and a common terminal of the first electronic switching circuit A high-frequency amplifier circuit, a mixing circuit in which the output of this high-frequency amplifier circuit is supplied to one input and the output of the local oscillation circuit is connected to the other input, and an intermediate-frequency amplification circuit to which the output of this mixing circuit is connected. Circuit, an output tuning circuit to which the output of the intermediate frequency amplifier circuit is connected, an output terminal to which the output of the output tuning circuit is connected, and a low-pass filter that passes the VHF band high frequency signal connected to the input terminal And an output signal of the low-pass filter is connected to the other selection terminal of the first electronic switching circuit and an output signal of the low-pass filter is connected to a common terminal. And a second electronic switching circuit and one selection terminal of the second electronic switching circuit.
A first trap circuit for trapping a VHF band high channel frequency; and a second trap circuit for trapping a VHF band low channel frequency connected to the other selection terminal of the second electronic switching circuit. When receiving a high frequency signal in the UHF band, one selection terminal of the first electronic switching circuit is turned on and the other selection terminal is turned off, and when the high frequency signal of the VHF band is received, the first electronic switching circuit is selected. The other selection terminal of the circuit is turned on and the one selection terminal is turned off. When receiving a low channel in the VHF band, one selection terminal of the second electronic switching circuit is turned on and the other selection terminal is turned off. When receiving a high channel in the VHF band, the other selection terminal of the second electronic switching circuit is turned on and one selection terminal is turned off. Integrated electronic tuning tuner.