JPH06252705A - Electronic allytuned receiver - Google Patents

Abstract

PURPOSE:To set the receiver to an always best tracking state even when a bias voltage subject to tracking adjustment is changed from an optimum value. CONSTITUTION:The receiver is provided with a control means 16 which stores information relating to an optimum bias voltage to a voltage variable reactance element at which a tracking error is minimized corresponding to an optionally selected frequency in a reception band to a storage means 18 in the production process, gives an optimum bias voltage obtained at each occasion to the voltage variable reactance element in the reception process of a frequency of a broadcast station actually and gives a bias voltage obtained arithmetically based on an optimum bias voltage obtained in the production process to the voltage variable reactance element in the reception process of a frequency of the absence of a broadcast station. Moreover, the control means 16 sets and applies an optimum bias voltage to receptible representative frequencies in a reception band in the actual reception and applies a bias voltage obtained arithmetically based on the optimum bias voltage with respect to the representative frequency to frequencies other than the representative frequencies to the voltage variable reactance element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic tuning receiver using a variable voltage reactance element in a tuning circuit.

[0002]

2. Description of the Related Art Conventionally, an electronic tuning receiver using a variable voltage reactance element for a tuning circuit is known.

In this kind of electronic tuning receiver, tracking error occurs due to the characteristics of the voltage variable reactance element such as the voltage variable capacitance diode used in the high frequency tuning circuit and the local oscillation circuit.

When a tracking error occurs in this way,
There is a variation in reception sensitivity, which causes a problem such as stopping at an undesired broadcast frequency during automatic channel selection.

Therefore, conventionally, a variable inductance coil, a trimmer capacitor or the like is arranged in the high frequency tuning circuit and the local oscillation circuit, and the variable inductance coil, the trimmer capacitor or the like is adjusted at the time of manufacture of the electronic tuning receiver to prevent a tracking error. I try to make it smaller.

Further, in the automatic channel selection receiver, generally, the high frequency signal level at which practical reception quality is obtained is detected, and further the intermediate frequency is accurately detected, so that the sweep stop at the time of automatic channel selection is performed. I have to.

[0007]

According to the above-mentioned conventional technique, since it is necessary to make an adjustment for reducing the tracking error at the time of manufacturing the receiver, the tuning circuit is arranged at an easily adjustable position. However, there is a problem that the degree of freedom in design is reduced due to the restriction of.

Further, since the adjustment work is also performed artificially, the adjustment accuracy becomes insufficient, and the time required for the adjustment becomes long, which is inefficient.

Furthermore, in order to detect the high frequency signal level required for the sweep stop operation during automatic channel selection, it is necessary to adjust the individual receivers in order to correct the variations in the receiving sensitivity of the receivers, and many receivers are It was a problem when producing.

For this reason, the applicant of the present application previously filed Japanese Patent Application No. 3-1.
No. 93100, "An electronic tuning receiver using a voltage variable reactance element for a tuning circuit, which corresponds to a frequency arbitrarily selected in a reception band and minimizes a tracking error at the frequency. Storage means for storing information on the voltage supplied to the voltage variable reactance element, and controlling the reception frequency, determining whether or not the reception frequency is the frequency stored in the storage means, and storing the reception frequency in the storage means. When the frequency is different, the information stored in the storage means is supplied to the voltage variable reactance element, and when the reception frequency is different from the frequency stored in the storage means, the information is stored in the storage means near the reception frequency. The voltage supplied to the voltage variable reactance element at the reception frequency based on the information corresponding to the frequency To obtain information for electronic tuning receiver, characterized in that the information comprises a control means for supplying to the voltage variable reactance element. "Proposed.

However, if the voltage (bias voltage) supplied to the voltage variable reactance element is adjusted only during production adjustment, if the optimum bias voltage value changes due to secular change or the like, an error occurs in the adjusted optimum bias voltage value. Will continue to occur, resulting in poor sensitivity and deterioration of basic characteristics of the receiver such as distortion and stereo separation characteristics.

[0012]

In view of the above points, the present invention uses a variable voltage reactance element in a tuning circuit, and in a production process, corresponds to a frequency arbitrarily selected in a reception band, In an electronic tuning receiver equipped with storage means for storing information on the optimum bias voltage to the voltage variable reactance element for minimizing the tracking error in the The optimum bias voltage obtained is supplied to the voltage variable reactance element, and in the reception process of a frequency without a broadcasting station, the bias voltage arithmetically obtained based on the optimum bias voltage obtained in the production process is used as the voltage variable reactance element. And a control means for supplying the

Further, according to the present invention, a variable voltage reactance element is used in the tuning circuit, and in the production process, the variable voltage reactance corresponding to a frequency arbitrarily selected in the reception band minimizes the tracking error at the frequency. In an electronic tuning receiver provided with a storage means for storing information on the optimum bias voltage to the reactance element, at the time of actual reception, the optimum bias voltage is set for a typical frequency that can be received within the reception band, and the voltage is set. A control means for supplying to the variable reactance element a bias voltage arithmetically obtained based on the optimum bias voltage of the representative frequency for frequencies other than the representative frequency is provided. Is characterized by.

[0014]

According to the present invention, the optimum bias voltage obtained each time is supplied to the voltage variable reactance element not only at the time of production adjustment but also in the process of actually receiving a certain frequency of the broadcasting station, so that the frequency without the broadcasting station is supplied. In the receiving process, the bias voltage arithmetically obtained based on the optimum bias voltage obtained in the production process is supplied to the voltage variable reactance element. Even if the value changes from the optimum value, the receiver can always be set in the best tracking state.

Further, according to another embodiment of the present invention, at the time of actual reception, an optimum bias voltage is set for a receivable representative frequency within a reception band and supplied to the voltage variable reactance element, and For frequencies other than the frequency, the bias voltage obtained arithmetically based on the optimum bias voltage of the representative frequency is supplied to the voltage variable reactance element. Even if the bias voltage value after tracking adjustment changes from the optimum value, the receiver can always be set in the best tracking state.

[0016]

FIG. 1 is a diagram showing an embodiment of the present invention.
In FIG. 1, 1 is an antenna, 2 is an antenna tuning circuit including a voltage variable capacitance diode, 3 is a high frequency amplifier circuit including a voltage variable capacitance diode, and 4 is a local oscillation circuit.
An LL circuit, which includes a voltage variable capacitance diode and which outputs a local oscillation signal, and a voltage controlled oscillator (VCO) 5
Programmable frequency divider 6 that divides the output signal from CO5 by N, phase comparator 8 that compares the output signal from programmable frequency divider 6 with the oscillation signal from reference oscillation circuit 7, and this phase comparator 8 is supplied with the output signal, and the control signal is supplied to the VCO 5 based on the output signal. 10 is a high frequency amplifier circuit 3
Mixing circuit for deriving a desired intermediate frequency signal based on the high frequency signal from the VCO 5 and the oscillation signal from the VCO 5, 11 is an intermediate frequency amplifying circuit for amplifying the intermediate frequency signal from the mixing circuit 10, and 12 is the intermediate frequency amplifying circuit 11 , A stereo demodulation circuit for demodulating the detection signal from the detection circuit 12 in stereo, 14
Is a level detection circuit that detects the level of the intermediate frequency signal and outputs a signal corresponding to the level, and 15 is a first level conversion circuit that converts the output signal from the level detection circuit 14 into a digital signal
An AD conversion circuit 16 is a control circuit which outputs a frequency division ratio data to a programmable frequency divider 6 which constitutes the PLL circuit 4 and is supplied with a digital signal from the AD conversion circuit 15, which is a microcomputer. Composed of. Reference numeral 17 is a second AD conversion circuit that converts the signal output from the low-pass filter 9 that constitutes the PLL circuit 4 into a digital signal, 18 is a memory, and 19 is a signal for performing a tuning instruction or the like to the control circuit 16. A key input unit for inputting, 20 is a first DA converter for converting the digital information supplied from the control circuit 16 into an analog signal (DC voltage) and supplying it to the variable capacitance diode provided in the high frequency amplifier circuit 3. Circuit, 21
Is a second DA conversion circuit for converting the digital information supplied from the control circuit 16 into an analog signal (DC voltage) and supplying it to the variable capacitance diode provided in the antenna tuning circuit 2. Reference numeral 22 is an attenuator inserted on the input side of the antenna tuning circuit 2.

In the memory 18, the voltage supplied to the variable capacitance diode provided in the antenna tuning circuit and the high frequency amplifying circuit for minimizing the tracking error at a frequency arbitrarily selected in the reception band ( Digital information related to the bias voltage is stored corresponding to the frequency.

Next, the operation of storing information in the memory 18 during production adjustment will be described.

First, the supply voltage (bias voltage) to the variable capacitance diode of the antenna tuning circuit 2 and the high frequency amplifier circuit 3 becomes substantially the same as the supply voltage to the variable capacitance diode of the VCO 5 within the reception band. Set each constant of the circuit as follows.

Next, a high-frequency signal having a small to medium electric field strength is supplied as an antenna input so that the level detection circuit 14 can detect the level. It is assumed that this high frequency signal is adapted to change its frequency when adjusting the reception frequency of the receiver.

When the receiver is controlled so as to tune to an arbitrary frequency F within the reception band by operating the key input unit 19,
The control circuit 16 supplies the frequency division ratio data corresponding to the frequency F to the programmable frequency divider 6 of the PLL circuit 4 to supply V
The oscillation frequency of CO5 is controlled to be F + FIF or F-FIF. Here, FIF is the frequency of the intermediate frequency signal.

When the VCO 5 locks to its oscillation frequency, the second AD conversion circuit 17 converts the control voltage to the VCO 5 into a digital signal and supplies it to the control circuit 16.
The control circuit 16 sends the digital signal to the first and second DAs.
It is supplied to the conversion circuits 20 and 21, and at this time, the first AD
The digital information about the received electric field strength supplied from the conversion circuit 15 is stored in the memory 18.

Next, the value of the digital signal supplied to the first DA conversion circuit 20 is fixed, and the value of the digital signal supplied to the second DA conversion circuit 21 is changed from the previously set value to the + and-sides. The value of the second DA conversion circuit 21 when the output value from the first AD conversion circuit 15 becomes maximum is changed by slightly changing the value of the digital signal from the first AD conversion circuit 15 (that is, the received electric field strength). Find this and store it in memory 18
Is stored in association with the received frequency.

Thereafter, the value of the digital signal supplied to the second DA conversion circuit 21 is fixed to the value stored in the memory 18 by the above operation, and the digital signal supplied to the first DA conversion circuit 20 is fixed in the same manner as described above. The value is slightly changed to + side and-side. As a result, the value from the first DA conversion circuit 20 when the output of the first AD conversion circuit 15 becomes maximum is obtained, and this value is used to store the reception frequency and the second DA conversion circuit 2 previously stored.
It is stored in the memory 18 in association with the value of 1.

The above operation is performed for each frequency arbitrarily selected within the reception band, and the value of the second DA conversion circuit 21 and the first DA conversion circuit 20 are associated with the respective frequencies at that time.
The value of is stored in the memory 18.

For example, as shown in FIG. 2, five frequencies (F1, F2, F3, F4, F5) are selected within the reception band, the above operation is performed for each frequency, and the correction data (D
1, D2, D3, D4, D5) are stored in the memory 18.

Next, the receiving operation in the present invention will be described.

Now, when the preset key of the key input unit 19 is operated and the actual reception, for example, the broadcasting station A (frequency f1) is received, the control circuit 1 is operated according to the operation of the key.
Reference numeral 6 supplies the frequency division ratio data corresponding to the broadcasting station A to the programmable frequency divider 6 to control the PLL circuit 4 to oscillate at a frequency of f1-FIF or f1 + FIF, and at the time of the production adjustment. Tracking adjustment is performed in the same manner.

In this way, the tracking error is automatically set to the minimum state, and the signal can be received with good reception sensitivity.

Incidentally, when the detection level (VIF) of the intermediate frequency is saturated at the time of receiving the broadcast, the control circuit 16
Then, the attenuator 22 is operated to attenuate the input signal, and VIF is adjusted to be in the linear region (region S-S 'in FIG. 3).

On the other hand, when receiving a frequency without a broadcasting station,
Frequencies F1, F2, F3, F4 set during production adjustment,
Based on the tracking correction value in F5, the tracking correction value obtained arithmetically, that is, the correction data corresponding to the frequencies located above and below the reception frequency of the frequencies stored in the memory 18 is calculated. After the correction data at the reception frequency is calculated by reading, for example, averaging the two, the calculated correction data is supplied to the first DA conversion circuit 20 and the second DA conversion circuit 21.

Therefore, also in this case, the tracking error is automatically set to a low level and the signal can be received with good reception sensitivity.

By the way, in the above embodiment, the case where the present invention is applied to the FM receiver has been described, but it goes without saying that it can also be applied to the AM receiver, and the number of frequencies stored in the storage means is limited to five. Not something.

FIG. 4 is a diagram showing the relationship between the reception frequency and tracking correction data when another embodiment of the present invention is used.

Next, the operation of another embodiment of the present invention will be described. Since the operation of the other embodiment of the present invention is basically the same as the operation of FIG. 1, the description of the operation already described will be omitted.

At the time of production adjustment, the antenna tuning circuit 2 and the high frequency amplifier circuit 3 are adjusted by the above-described method to set the tracking error to the minimum state, and then the sweep stop level at the time of automatic channel selection is set.

Next, the receiving operation will be described.

Now, when the automatic sweep key of the key input section 19 is operated to perform the automatic sweep operation, it is determined whether or not the high frequency signal level at each sweep frequency is equal to or higher than a predetermined sweep stop level. . That is, the information about the intermediate frequency signal level corresponding to the desired high frequency signal level at which the sweep is to be stopped is read from the memory 18, and the digital signal about the intermediate frequency signal level read from the memory 18 and the intermediate frequency amplifier circuit 11 are read. The digital signal relating to the intermediate frequency signal level at each sweep frequency obtained through the level detection circuit 14 and the AD conversion circuit 15 is compared in the control circuit 16, and the intermediate frequency signal level at each sweep frequency is stored in the memory 18. It is determined whether or not it is higher than the stored predetermined intermediate frequency signal level (sweep stop level).

If the intermediate frequency signal level at each sweep frequency is equal to or higher than the predetermined sweep stop level, the sweep operation during automatic channel selection is stopped.

Then, the memory 18 stores the information on the frequency corresponding to the desired high frequency signal level at which the sweep is to be stopped, that is, the receivable frequency.

Next, from among receivable frequencies, typical tracking adjustment frequencies (f2, f3, f4, f5, f6 in FIG. 4) are selected so that the frequency intervals are most uniform.
Then, the frequencies f2, f2, f3, f4, f5, f6
Tracking adjustment is performed for each item in the same manner as during production adjustment.

When the intermediate frequency detection level (VIF) is saturated during broadcast reception, the control circuit 16 operates the attenuator 22 to attenuate the input signal and VIF as in the case described above. Is a linear region (S in Fig. 3
-S 'area).

On the other hand, for frequencies other than f2, f3, f4, f5 and f6, the above f2, f3, f4, f5 and f are set.
Based on the tracking correction value in 6, the control circuit 1
A trackinging correction value (value shown by a broken line in FIG. 4) obtained arithmetically in 6 is applied.

[0044]

According to the present invention, the optimum bias voltage obtained each time is supplied to the voltage variable reactance element not only during the production adjustment but also during the actual receiving process of a certain frequency of the broadcasting station, and In the process of receiving no frequency,
Since the bias voltage obtained arithmetically based on the optimum bias voltage obtained in the production process is supplied to the voltage variable reactance element, the bias voltage value after tracking adjustment has changed from the optimum value due to aging or the like. Even in this case, the receiver can always be set in the best tracking state, and the reception can be performed with the best characteristics.

According to another embodiment of the present invention, at the time of actual reception, an optimum bias voltage is set for a receivable representative frequency within the reception band and is supplied to the voltage variable reactance element, and the representative bias voltage is supplied to the voltage variable reactance element. For frequencies other than the frequency, the bias voltage obtained arithmetically based on the optimum bias voltage of the representative frequency is supplied to the voltage variable reactance element. Even if the tracking-adjusted bias voltage value changes from the optimum value, the receiver can always be set in the best tracking state, and reception can be performed with the best characteristics.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic tuning receiver of the present invention.

FIG. 2 is a diagram for explaining an embodiment of the present invention and is a diagram showing a relationship between a reception frequency and a tracking correction value.

FIG. 3 is a diagram for explaining the present invention and is a diagram showing a relationship between a received input intensity and an intermediate frequency detection level.

FIG. 4 is a diagram for explaining another embodiment of the present invention and is a diagram showing a relationship between a reception frequency and a tracking correction value.

[Explanation of symbols]

 2 antenna tuning circuit 3 high frequency amplifier circuit 14 level detection circuit 16 control circuit (control means) 18 memory (storage means) 22 attenuator

Claims (3)

[Claims] 1. A variable voltage reactance element is used for a tuning circuit, and in the production process, the variable voltage reactance element is adapted to minimize a tracking error at a frequency corresponding to an arbitrarily selected frequency within a reception band. In an electronic tuning receiver equipped with a storage means for storing information on the optimum bias voltage of, in the process of actually receiving a certain frequency of a broadcasting station, the optimum bias voltage obtained each time is supplied to the voltage variable reactance element. In a reception process of a frequency without a broadcasting station, a control means for supplying a bias voltage arithmetically obtained based on the optimum bias voltage obtained in the production process to the voltage variable reactance element is provided. Tuning receiver. 2. The voltage variable reactance element is used for the tuning circuit, and in the production process, the voltage variable reactance element which minimizes tracking error at the frequency corresponding to a frequency arbitrarily selected in the reception band is provided. In an electronic tuning receiver provided with a storage means for storing information on the optimum bias voltage of, the voltage variable reactance element is set by setting the optimum bias voltage for a typical receivable frequency within the reception band during actual reception. And a control means for supplying to the voltage variable reactance element a bias voltage that is arithmetically obtained based on the optimum bias voltage of the representative frequency for frequencies other than the representative frequency. An electronic tuning receiver. 3. The attenuator inserted in the input side of the antenna tuning circuit is operated by the control means when the intermediate frequency signal level is equal to or higher than a predetermined level. Electronic tuning receiver.