JPH11168399A - Reception circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electronically perform adjustment or the like and to easily automate the adjustment as well. SOLUTION: Tuning control signals for specifying desired signals are supplied from a control terminal 12 to a microprocessor 10 and the tuning control data X of a nonvolatile memory 11 are selected according to a carrier frequency F corresponding to the tuning control signals and supplied to a phase locked circuit 9. Further, the output voltage of the phase locked circuit 9 is supplied to a transistor 13, a control voltage from the transistor 13 is supplied to an oscillation circuit 7 and local oscillation signals for tuning and receiving the desired signals are generated. Also, the control voltage from the transistor 13 is supplied to an arithmetic circuit 16, the tuning control data A of the nonvolatile memory 11 are selected and the data A are supplied through a D/A conversion circuit 17 to the arithmetic circuit 16 and added/subtracted to/from the control voltage. Then, the control voltage from the arithmetic circuit 16 is supplied to a tracking filter 5 and a pass band is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving circuit suitable for use in a tuner having, for example, a voltage control tuning circuit.

[0002]

2. Description of the Related Art For example, in a tuner device having a voltage control tuning circuit, a control voltage corresponding to a carrier frequency of a desired reception signal is formed, and this control voltage is supplied to a voltage control tuning circuit to generate a desired reception signal. For tuning reception. As a receiving circuit used in such a tuner device, for example, a circuit as shown in FIG. 3 is conventionally implemented.

In FIG. 3, a reception signal received by an antenna 31 is supplied to a buffer (B) amplifier 33 through a tracking filter 32. This buffer amplifier 3
3 is supplied to a mixing circuit 36 through tracking filters 34 and 35. The mixing circuit 36 is supplied with a local oscillation signal from an oscillation circuit (VCO) 37. A local oscillation signal is mixed with the above-mentioned received signal, and a desired received signal is converted to an intermediate frequency (IF).
Converted to a signal. Further, the converted intermediate frequency signal is supplied to a demodulation circuit 38, and a desired received signal is demodulated.

In this circuit, a control voltage corresponding to a carrier frequency of a desired received signal is supplied to an oscillation circuit 37, and a tuned reception of the desired received signal is performed. That is, the oscillating signal from the oscillating circuit 37 is supplied to the mixing circuit 36, and the oscillating signal is also supplied to, for example, a phase lock circuit (PLL) 39. To this phase lock circuit 39, for example, a tuning control signal for designating a desired reception signal from the control terminal 40 is supplied, and according to the tuning control signal, the above-described oscillation signal and a built-in arbitrary reference oscillation signal are converted. An output voltage is formed so as to have a predetermined relationship.

Further, an output voltage from the phase lock circuit 39 is supplied to a base of a transistor 41, an emitter of the transistor 41 is grounded, and a collector is supplied with power from a power supply terminal 43 through a resistor 42. Then, a control voltage is extracted from the collector of the transistor 41 and supplied to the oscillation circuit 37 described above. In this way, a control voltage for tuning reception to a desired reception signal according to the above-described tuning control signal is formed, and this control voltage is supplied to the oscillation circuit 37 to tune and receive the desired reception signal. Is generated.

At the same time, the control voltage is also supplied to the tracking filters 32, 34, and 35 to control the pass band for extracting the desired reception signal.

That is, in the above-described circuit, the oscillation circuit 37 and the tracking filters 32, 34, 35 each control the oscillation frequency and the pass band using, for example, a voltage-controlled variable capacitance diode. In this case, if the characteristics of the variable capacitance diodes are equal, the control voltage at that time becomes equal. Therefore, the control of the tracking filters 32, 34, and 35 can be performed using the control voltage supplied to the oscillation circuit 37 as it is. Thus, a desired received signal can be extracted.

[0008]

However, in the above-mentioned circuit, for example, in a circuit handling a high frequency, it is not possible to avoid the influence of the parasitic capacitance in the wiring and the like. Therefore, no matter how much the characteristics of the variable capacitance diodes are equal, the capacitance in the circuit may not be equal. Therefore, in the conventional circuit, for example, the values of the oscillation circuit and other fixed elements connected to the tracking filter are selected so that the optimum values of the control of the oscillation frequency and the pass band are obtained. However, it is extremely difficult to obtain an optimum value by such a method.

Further, for example, an adjusting means such as a so-called trimmer capacitor is provided for each variable capacitance diode provided in each circuit, and the above-mentioned parasitic capacitance and the like are adjusted to thereby adjust the frequency controlled by the single control voltage. Are also made to have the same control characteristics. However, in this method, for example, adjustment of the above-described trimmer capacitor or the like requires mechanical adjustment means such as rotation of a screw, for example, and it is extremely difficult to automate the adjustment. There is a high possibility of occurrence of fluctuations and the like.

The present application has been made in view of such a point, and the problem to be solved is that the conventional circuit cannot avoid the influence of the parasitic capacitance and the like when handling a high frequency, for example. On the other hand, it is difficult to select the value of another fixed element or the like to obtain the optimum value of the adjustment, and it is also difficult to automate the adjustment.

[0011]

Therefore, in the present invention, control values for controlling a plurality of voltage control tuning means are stored, respectively, and control of the plurality of voltage control tuning means is performed using the stored control values. According to this, it is possible to electronically perform the adjustment of the element and the like, and it is possible to easily perform the adjustment to the optimum value, and also to facilitate the automatic adjustment and the like. In addition, the possibility of physical change or fluctuation after the adjustment can be extremely reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a control circuit for controlling a plurality of voltage control tuning means corresponding to a carrier frequency of a received signal in a receiving circuit for selecting a reception signal using a plurality of voltage control tuning means. A storage means for storing each value is provided, a control value stored in the storage means is read out in accordance with a carrier frequency of a desired received signal, and a plurality of voltage control tuning means are controlled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a main part of an example of a tuner device to which a receiving circuit according to the present invention is applied.

In FIG. 1, a received signal received by an antenna 1 is supplied to a buffer (B) amplifier 3 through a tracking filter 2. The signal from the buffer amplifier 3 is supplied to the mixing circuit (mixer) 6 through the tracking filters 4 and 5. A local oscillation signal from an oscillation circuit (VCO) 7 is supplied to the mixing circuit 6. Then, a local oscillation signal is mixed with the above-mentioned received signal, and a desired received signal is converted into an intermediate frequency (IF) signal. Further, the converted intermediate frequency signal is supplied to a demodulation circuit 8, and a desired received signal is demodulated.

In this circuit, a control voltage corresponding to the carrier frequency of the desired received signal is supplied to the oscillation circuit 7 to perform the tuned reception of the desired received signal. That is, the oscillating signal from the oscillating circuit 7 is supplied to the mixing circuit 6, and the oscillating signal is supplied to, for example, a phase lock circuit (PL
L) 9 as well. The phase lock circuit 9 is supplied with tuning control data for specifying a desired reception signal from, for example, a microprocessor (CPU) 10.
According to the tuning control data, an output voltage is formed so that the above-mentioned oscillation signal and a built-in reference oscillation signal have a predetermined relationship.

Here, the above-mentioned microprocessor 10 is provided with a storage means comprising, for example, a nonvolatile memory 11. For example, as shown in FIG. 2, the nonvolatile memory 11 stores a control value (tuning control data X) for controlling the frequency of the local oscillation signal corresponding to the carrier frequency F of the received signal. . When a tuning control signal designating the above-described desired reception signal is supplied from the control terminal 12 to the microprocessor 10, the tuning control stored in the nonvolatile memory 11 according to the carrier frequency F corresponding to the tuning control signal. Data X is selected and supplied to the phase lock circuit 9.

Further, an output voltage from the phase lock circuit 9 is supplied to a base of a transistor 13, an emitter of the transistor 13 is grounded, and a resistor 1
Power is supplied from a power supply terminal 15 through 4. Then, a control voltage is extracted from the collector of the transistor 13 and supplied to the oscillation circuit 7 described above. In this way, a control voltage for tuning reception to a desired reception signal according to the above-described tuning control signal is formed, and this control voltage is supplied to the oscillation circuit 7 to tune and receive the desired reception signal. Is generated.

At the same time, the control voltage from the transistor 13 is supplied to the arithmetic circuit 16. In addition, in the above-mentioned nonvolatile memory 11, for example, as shown in FIG.
5 control values (tuning control data A,
B, C) are stored. And the above-mentioned control terminal 12
For example, tuning control data A stored in the non-volatile memory 11 is selected in accordance with the carrier frequency F according to the tuning control signal from, and this data A is supplied to the arithmetic circuit 16 through the D / A conversion circuit 17, It is added to or subtracted from the control voltage described above.

The control voltage from the arithmetic circuit 16 is supplied to the tracking filter 5 to control the pass band of the tracking filter 5 for extracting the desired reception signal. That is, for the control value for controlling the frequency of the local oscillation signal supplied to the phase lock circuit 9 described above, for example, a control value for adjusting a variation due to the influence of the parasitic capacitance of the tracking filter 5 is included in the tuning control data A. The pass band of the tracking filter 5 is controlled by the control voltage obtained by adding and subtracting the adjustment amount of the data A.

Further, the control voltage from the arithmetic circuit 16 is supplied to arithmetic circuits 18 and 19 which are sequentially provided in a dependent manner.
In addition, tuning control data B stored in the nonvolatile memory 11,
C is supplied to arithmetic circuits 18 and 19 through D / A conversion circuits 20 and 21, respectively, and is added to and subtracted from control voltages sequentially supplied from arithmetic circuit 16, respectively. The passbands of the tracking filters 2 and 4 are controlled by the control voltages obtained by adding and subtracting the adjustments of the data B and C.

As a result, for example, the variation due to the influence of the parasitic capacitance of the tracking filters 2, 4, and 5 is adjusted, and extremely good reception can be performed. In this case, the tuning control data A, B, and C for this adjustment are stored in, for example, the nonvolatile memory 11, and for these adjustments, for example, a screw of a conventional trimmer capacitor is rotated. It is not necessary to use any special mechanical adjustment means, and automation of adjustment can be easily performed.

Therefore, in this device, the control values for controlling the plurality of voltage control tuning means are stored, respectively, and the plurality of voltage control tuning means are controlled using the stored control values, thereby adjusting the elements and the like. Can be adjusted electronically, the adjustment to the optimum value can be easily performed, the automation of the adjustment can be easily performed, and the possibility of physical change or fluctuation after the adjustment can be obtained. Can also be extremely low.

Thus, in the conventional circuit, for example, when dealing with high frequencies, the influence of parasitic capacitance and the like cannot be avoided. On the other hand, the value of another fixed element or the like is selected to obtain the optimum value of adjustment. However, according to the present invention, these problems can be easily solved.

In the circuit described above, for example, the control voltage supplied to the oscillation circuit 7 is a voltage that is changed to about 0.5 to 25V. On the other hand, the control voltage for the fluctuation supplied to the tracking filters 2, 4, and 5 is about ± 1V. Therefore, in the above-described circuit, the data amount of the tuning control data A, B, and C for controlling the pass band of the tracking filters 2, 4, and 5 is smaller than the tuning control data X for controlling the frequency of the local oscillation signal. Only need to
Alternatively, if the data amount is the same, high-precision adjustment can be performed.

In the above circuit, the arithmetic circuit 16,
The arrangement of the circuits 18 and 19 can be achieved, for example, by directly supplying the control voltage from the transistor 13 to the respective arithmetic circuits 16, 18 and 19 without the subordinate arrangement as described above.
The adjustment values from the / A conversion circuits 17, 20, 21 may be added and subtracted and supplied to the tracking filters 2, 4, 5.

According to the above-described receiving circuit, in the receiving circuit for selecting the received signal using the plurality of voltage control tuning means, the control for controlling the plurality of voltage control tuning means corresponding to the carrier frequency of the received signal is provided. By providing storage means for storing the respective values, reading out the control values stored in the storage means in accordance with the carrier frequency of the desired received signal, and controlling the plurality of voltage control tuning means, the optimum value can be easily obtained. Can be adjusted, automation of the adjustment can be easily performed, and the possibility of physical change or change after the adjustment can be extremely reduced.

[0027]

According to the first aspect of the present invention, control values for controlling a plurality of voltage control tuning means are stored, respectively.
By controlling the plurality of voltage control tuning means using the stored control values, the adjustment of the elements and the like can be performed electronically, and the adjustment to the optimum value can be easily performed. Can be easily automated, and the possibility of physical change or fluctuation after adjustment can be extremely reduced.

As a result, in the conventional circuit, for example, when dealing with high frequencies, the influence of parasitic capacitance and the like cannot be avoided. On the other hand, the value of another fixed element or the like is selected to obtain the optimum value for adjustment. However, according to the present invention, these problems can be easily solved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an example of a receiving circuit to which the present invention is applied.

FIG. 2 is a diagram for explaining this.

FIG. 3 is a configuration diagram of a main part of a conventional receiving circuit.

[Explanation of symbols]

1 ... antenna, 2, 4, 5 ... tracking filter, 3
... buffer (B) amplifier, 6 ... mixing circuit (mixer),
7 oscillation circuit (VCO), 8 demodulation circuit, 9 phase lock circuit (PLL), 10 microprocessor (CP
U), 11: nonvolatile memory, 12: control terminal, 13: transistor, 14: resistor, 15: power supply terminal, 16, 1
8, 19 ... arithmetic circuit, 17, 20, 21 ... D / A conversion circuit

Claims (5)

[Claims] 1. A receiving circuit for selecting a received signal using a plurality of voltage control tuning means, wherein a control value for controlling the plurality of voltage control tuning means is stored corresponding to a carrier frequency of the received signal. A receiving circuit, comprising: a storage unit that reads a control value stored in the storage unit according to a desired carrier frequency of the reception signal, and controls the plurality of voltage control tuning units. 2. The receiving circuit according to claim 1, wherein said plurality of voltage control tuning means supplies said received signal to a mixing circuit via a tracking filter, and outputs a local oscillation signal supplied to said mixing circuit. A frequency and a pass band of the tracking filter are controlled to convert a desired carrier frequency of the received signal to a predetermined intermediate frequency, and a frequency of the local oscillation signal corresponding to the carrier frequency of the received signal. Storage means for storing a control value for controlling the control value and a control value for controlling the pass band of the tracking filter, and reading out the control value stored in the storage means in accordance with a desired carrier frequency of the received signal, A receiving circuit for controlling a frequency of the local oscillation signal and a pass band of the tracking filter. 3. The receiving circuit according to claim 2, wherein a control signal for controlling a frequency of the local oscillation signal is supplied to a local oscillation circuit, and the control signal is supplied to the tracking filter through an addition / subtraction circuit. Storing a control value for controlling the frequency of the local oscillation signal and a difference value of a control value for controlling a pass band of the tracking filter with respect to a control value for controlling the frequency of the local oscillation signal in the storage means. Receiving circuit. 4. The receiving circuit according to claim 2, wherein a plurality of circuits are provided in said tracking filter, and control values for controlling pass bands of said plurality of circuits of said tracking filter are stored in said storage means. A receiving circuit, characterized in that: 5. The receiving circuit according to claim 2, wherein the tracking filter includes a plurality of circuits, supplies a control signal for controlling a frequency of the local oscillation signal to the local oscillation circuit, and supplies the control signal to the local oscillation circuit. A plurality of circuits of the tracking filter are supplied to a plurality of circuits of the tracking filter through an addition / subtraction circuit, and a control value for controlling a frequency of the local oscillation signal and a control value for controlling a frequency of the local oscillation signal are controlled by the plurality of circuits of the tracking filter. A receiving circuit, wherein a difference value of a control value for controlling a pass band and a difference value of the control value are stored in the storage means.