JPH0815251B2 - Electronic tuning receiver - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic tuning receiver.

2. Description of the Related Art In recent years, the mainstream of the receiver is shifting from the variable capacitor method to the electronic tuning method with the development of IC, and MW / FM / VHF /
It is known that the UHF band can be received.

An example of a conventional electronic tuning receiver will be described below with reference to the drawings.

FIG. 4 is a block diagram of a conventional electronic tuning receiver having FM / VHF / UHF band. In FIG. 4, 1 is a key switch for switching a plurality of reception frequency bands, 2 is a reception frequency band selected by detecting that the key switch 1 is closed, and a plurality of outputs corresponding to the reception frequency band are provided. The receiving frequency band switching means to be generated, 9 is an FM output terminal, 10 is a VHFL output terminal, 11 is a VHFH output terminal,
12 is an output terminal for UHF. 101 is an FM voltage control type oscillation means driven by the output of the reception frequency band switching means 2;
Reference numeral 102 is a VHF / UHF voltage control type oscillation means driven by a plurality of outputs of the reception frequency band switching means 2, and 103 is a VHF / UH.
A prescaler for dividing the output of the F voltage control type oscillation means 102 into 1 / N ₁ is an electronic switch device 104 controlled by the output of the reception frequency band switching means 2 and is the FM voltage control type oscillation means 101. Output and voltage controlled oscillator for VHF / UHF 102
The output of is switched. Reference numeral 105 denotes a programmable counter that divides the outputs of the voltage control type oscillating means 101 and 102 selected by the electronic switch device 104, 106 denotes a dividing ratio calculating means that receives a signal from the receiving frequency band switching means 2 and calculates a dividing ratio, 107 is an up key that increases the reception frequency, 1
08 is a down key for decreasing the reception frequency, 6 is an input terminal for a reference frequency obtained by dividing the frequency from a crystal oscillator, 7 is a phase comparator for performing a phase comparison between the reference frequency and the output of the programmable counter 5, 8 Is a low-pass means for removing the high-frequency component of the output of the phase comparator 7, and applies the output to the FM voltage-controlled oscillation means 101 and VHF / UHF voltage-controlled oscillation means 102. Reference numeral 77 is an input terminal of the low-pass means, and 72 is an output terminal of the low-pass means.

Regarding the electronic tuning receiver configured as above,
The operation will be described below. First, the receiver must obtain local oscillation frequencies separated by an intermediate frequency in order to receive a desired reception frequency. The more accurate this local oscillation frequency, the higher the reception accuracy. Therefore, PL
It has been conventionally performed to obtain an accurate local oscillation frequency by using L technology. FIG. 4 shows the PLL configuration. First, each time the key switch 1 is closed, the reception frequency band switching means 2 changes the reception frequency band from FM to VH.
It switches to F and UHF and generates an output according to the reception frequency band. Now, it is assumed that the mobile phone is in the FM state.
H for the voltage controlled oscillator 101 for FM and the electronic switch device 104
Signal is sent to start operation and frequency division ratio calculation means
The information is sent to 106, and the division ratio calculation means 106 sets the division ratio N ₃ corresponding to the desired reception frequency. The output of the FM voltage controlled oscillator 101 is sent to the programmable counter 105 via the electronic switch device 104 and is 1 / N ₃ .
The phase comparator 7 performs phase comparison between the reference frequency and the output of the programmable counter 105, and an error output ΔV corresponding to the phase difference is output. That is, the local oscillation frequency is os
c and r is the reference frequency, ΔV is output so that The error output is passed through the low-pass means 8 to remove the high-frequency component and applied to the FM voltage control type oscillation means 101. A variable capacitance diode is generally used as a means for changing the oscillation frequency of the voltage control type oscillation means 101. When ΔV is positive, the capacitance of the variable capacitance diode decreases and the oscillation frequency increases. On the contrary, when ΔV is negative, the oscillation frequency decreases. Due to this operation, ΔV is 0
The oscillating frequency shifts until it becomes. When ΔV becomes 0, the so-called PLL is locked, and desired reception is performed. Next, when the key switch 1 is closed so as to be in the reception frequency band of VHF, an H signal is sent from the reception frequency band switching means 2 to the VHF / UHF voltage control type oscillation means 102 to oscillate the VHF band. Start.

The three lines connected from the reception frequency band switching means 2 to the VHF / UHF voltage control type oscillation means 102 correspond to the output lines for VHFL, VHFH.UHF. Further, the information is sent to the frequency division ratio calculation means 106, and the frequency division ratio calculation means 106 sets the frequency division ratio N ₃ ′ corresponding to the desired reception frequency. The output of the VHF / UHF voltage control type oscillating means 102 is 1 / N ₁ by the prescaler 103, and the programmable counter 1
It is sent to 05 and is further 1 / N ₃ ′. Next, it is sent to the phase comparator 7 and compared in phase with the reference frequency, and an error output ΔV corresponding to the phase difference is output. That is The error output ΔV is output so that The following operation is FM
Same as time.

 The description for the UHF band is similar to that for the VHF band.

FIG. 5 shows an embodiment of the low-pass means. 78 to 82 are resistors, 83 to 85 are capacitors, and 86 and 87 are transistors.

Problems to be Solved by the Invention However, in the above-described configuration, the FM tuner and the VHF / UHF tuner are separately required, resulting in high cost. In addition, each voltage control type oscillating means has two outputs, and it is complicated to switch them by an electronic switch device. Especially, switching operation at a high frequency increases noise and tends to cause instability. I had a problem.

In view of the above problems, the present invention provides an FM / VHF / UHF electronic tuning receiver in which the output of the voltage control type oscillating means is unified and directly connected to the input of the prescaler to reduce the FM / VHF / UHF reception frequency band. Switching is performed by applying a DC voltage according to each frequency band to the voltage control type oscillating means and the prescaler, and the FM / VHF / UHF tuner is integrated to reduce costs and eliminate the need for high frequency switching. And an electronic tuning receiver with high stability.

Means for Solving the Problems In order to solve the above problems, an electronic tuning receiver of the present invention detects a key switch for switching a plurality of reception frequency bands and the fact that the key switch is closed. Reception frequency band switching means for selecting a reception frequency band and generating a plurality of outputs corresponding to the reception frequency band, and a voltage for switching a plurality of reception frequency bands by a plurality of outputs of the reception frequency band switching means to operate. A single output of the control-type oscillating means and the voltage-controlled oscillating means is divided, and a prescaler whose division ratio is set by the output of the reception frequency band switching means and the output of the prescaler are divided. A programmable counter, a frequency division ratio calculation means for calculating a frequency division ratio based on the information of the reception frequency band switching means, and setting the frequency division ratio of the programmable counter; A phase comparator for phase comparison with the output of the programmable counter and a low-pass means for removing a high-pass component of the output of the phase comparator are provided, and the output of the low-pass means is used for the voltage-controlled oscillation. It is provided with a configuration for applying to the means.

The present invention has the above-mentioned configuration, and unifies the outputs of the voltage control type oscillating means having a plurality of reception frequency bands, directly connects to the input of the prescaler for switching the frequency division ratio, and outputs by the reception frequency band switching means. By selecting the oscillation frequency of the voltage control type oscillation means and the frequency division ratio of the prescaler, the FM / VHF / UHF tuner can be unified, the cost can be reduced, and the electronic switching device for switching the high frequency can be provided outside the tuner. It is possible to realize a stable electronic tuning receiver without the need to provide it.

Embodiment An electronic tuning receiver according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an electronic tuning receiver according to the first embodiment of the present invention. In FIG. 1, the same reference numerals as those in the conventional example of FIG.
3 is a voltage controlled oscillator for FM / VHF / UHF driven by a plurality of outputs of the reception frequency band switching means 2 and 4 is the FM
This is a prescaler configured to switch the frequency division ratio of the output of the / VHF / UHF voltage control type oscillation means 3 by the UHF output of the reception frequency band switching means 2. Reference numeral 73 is a prescaler input terminal, 74 is a prescaler control terminal for switching the division ratio of the prescaler 4, 75 is a prescaler output terminal, and 76 is an output terminal of the programmable counter.

Regarding the electronic tuning receiver configured as above,
The operation will be described below with reference to FIGS. 1, 2 and 3.

First, FIG. 2 is a concrete circuit diagram of the FM / VHF / UHF voltage control type oscillating means 3, in which 13 to 20 are diodes and 21
~ 39 is a resistor, 40,41 is a PNP transistor, 42-47 is an NPN transistor, 48-62 is a capacitor, 63,64 is a variable capacitance diode, 65-71 is a coil, 97 is a voltage controlled oscillator for UHF, 98 Is a voltage controlled oscillator for FM / VHF, 99 is FM / VHF / U
An output buffer of the HF voltage control type oscillation means, and 100 is a switch circuit. FIG. 3 shows a specific circuit diagram of the prescaler 4, in which 88 is an input amplifier, 89 to 91 are flip-flops, 92 is an output buffer, 93 and 94 are inverter buffers, and 9 is a buffer.
Reference numeral 5 is a NOR circuit, and 96 is an EX-OR circuit. First, each time the key switch 1 is closed, the reception frequency band switching means 2 switches the reception frequency band from FM to VHF and then to UHF, and an output corresponding to the reception frequency band is generated.

Now, it is assumed that the mobile phone is in the FM state. A voltage H is applied to the FM / VHF / UHF voltage control type oscillation means 3 through the FM output terminal. The transistors 43 and 40 are turned on and the FM / VHF voltage control type oscillation means 98 operates. Also transistor 4
Since 1,42 is turned on and the diode 20 is cut off, the oscillation frequency is determined by the parallel resonance between the series circuit of the coils 68 and 69 and the series circuit of the capacitor 50 and the variable capacitance diode 63. The voltage control type oscillating means 98 operates for FM. The oscillation output is supplied to the base of the transistor 47 by the electromagnetic coupling of the coils 68, 69 and 71, and is supplied to the prescaler input terminal 73. Since the control terminal 74 for switching the division ratio of the prescaler 4 is L, the output of the NOR circuit 95 is H, the output of the EX-OR circuit 96 is H, and therefore the flip-flop 9
The M terminals of 0 and 91 become H, the flip-flops 90 and 91 pass through, and the input of the flip-flop 89 is divided only by 1/2 and supplied to the flip-flop output terminal 75 through the output buffer. On the other hand, the reception frequency band switching means 2 sends the information to the frequency division ratio calculation means 106, and the frequency division ratio calculation means 106 sets the frequency division ratio N ₃ corresponding to the desired reception frequency. VH
Similarly for FL, VHFH, and UHF, the division ratio is set by that information. Therefore, the FM oscillation output is the prescaler 4.
After being halved, it is 1 / N ₃ by the programmable counter and supplied to one input of the phase comparator 7. The reference frequency is input to the other input of the phase comparator 7, the output of the programmable counter 5 and the reference frequency are compared in phase, and an error output ΔV corresponding to the phase difference is output. That is, The error output ΔV is output so that This error output is passed through the low-pass means 8 to remove high-frequency components, and the FM / VHF
/ UHF is applied to the variable capacitance diode 63 of the voltage controlled oscillator 3. When ΔV is positive, the capacitance of the variable capacitance diode decreases and the oscillation frequency increases. On the contrary, when ΔV is negative, the oscillation frequency decreases. This operation causes the oscillation frequency to shift until ΔV becomes 0, and when ΔV becomes 0, the so-called PLL
Since it is locked, desired reception is performed. Then VH
FL means 1 to 3 channels of the TV, and operates in the same manner as in the case of the FM. Next, VHFH refers to channels 4 to 12 of the television, and the operation of VHFH will be described. Only the parts different from FM and VHFL will be explained. The output terminal 11 for VHFH becomes H, the transistor 44 turns on, the diode 20 turns on,
Both ends of the coil 69 are AC-grounded. Thus coil 68
Only, the L value decreases, the oscillation frequency increases, and VHFH
It becomes the oscillation output of. Other operations are the same as in FM.
Next, the case of UHF will be described. The H voltage is applied to the FM / VHF / UHF voltage control type oscillation means 3 via the UHF output terminal 12, and the H voltage is applied to the control terminal 74 of the prescaler 4. A voltage is supplied to the UHF voltage control type oscillation means 97, and the oscillation frequency is determined by the parallel resonance of the coil 65 and the variable capacitance diode 64. The oscillation output is supplied to the base of the transistor 47 by the electromagnetic coupling of the coils 66 and 71, and is supplied to the prescaler input terminal 73. On the other hand, since the control terminal 74 for switching the division ratio of the prescaler is H, the output of the NOR circuit 95 and the output of the EX-OR circuit 96 are both L, and the input signal of the prescaler is divided by 1/8 and the output terminal of the prescaler is divided. Is output to. Dividing by 1/2 for FM / VHF and dividing by 1/8 for UHF is the upper operating frequency of programmable counter 5.
This is to prevent it from exceeding 130MHz. The maximum local oscillation frequency of VHF is 211 MHz, so if you divide it by 1/2, it becomes 105.5 MHz, UHF
The maximum local oscillation frequency of is 759MHz, which is 9 when divided by 1/8.
It is 4.875 MHz, and in both cases, it does not exceed the operation upper limit frequency of 130 MHz of the programmable counter 5. Other operations are the same as in FM.

As described above, according to the present embodiment, the voltage control type oscillating means which operates by switching the plurality of reception frequency bands by the plurality of outputs of the reception frequency band switching means, and the single voltage control type oscillating means. By dividing the output and providing a prescaler whose division ratio is set by the output of the reception frequency band switching means, an FM / VHF / UHF tuner can be integrated, and cost reduction and high frequency switching can be performed. It is possible to realize a stable electronic tuning receiver without providing a switch operation outside the tuner.

Although the output terminal for UHF is used for the switching signal of the division ratio of the prescaler 4, the output terminals for FM, VHFL and VHFH may be used.

EFFECTS OF THE INVENTION As described above, according to the present invention, the voltage control type oscillation means for switching and operating a plurality of reception frequency bands by the plurality of outputs of the reception frequency band switching means, and the single voltage control type oscillation means. An electronic switch that divides the output and provides a prescaler whose division ratio is set by the output of the reception frequency band switching means to integrate the FM / VHF / UHF tuner, reduce costs, and switch high frequencies. It is possible to realize a stable electronic tuning receiver without the operation being provided outside the tuner.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic tuning receiver in one embodiment of the present invention, FIG. 2 is a concrete circuit diagram of the voltage control type oscillation means of FIG. 1, and FIG. 3 is a concrete circuit diagram of the prescaler of FIG. 4, FIG. 4 is a block diagram of a conventional electronic tuning receiver, and FIG. 5 is a concrete circuit diagram of the low-pass means of FIG. 1 ... Key switch, 2 ... Reception frequency band switching means, 3
...... Voltage control type oscillation means, 4 ...... Prescaler, 5 ……
Programmable counter, 6 ... Reference frequency input terminal,
106: Frequency division ratio calculation means, 7: Phase comparator, 8: Low-pass means.

Claims (1)

[Claims] 1. A key switch for switching a plurality of reception frequency bands, and a reception unit for detecting a closing of the key switch to select a reception frequency band and generating a plurality of outputs corresponding to the reception frequency band. Frequency band switching means, voltage control type oscillating means for operating by switching a plurality of reception frequency bands by a plurality of outputs of the reception frequency band switching means, and frequency division of a single output of the voltage control type oscillating means A prescaler whose frequency division ratio is set by the output of the reception frequency band switching means, a programmable counter for frequency dividing the output of the prescaler, and a frequency division ratio calculated by the information of the reception frequency band switching means, A frequency division ratio calculating means for setting a frequency division ratio of the programmable counter; a phase comparator for performing a phase comparison between a reference frequency and an output of the programmable counter; An electronic tuning receiver comprising low-pass means for removing a high-pass component of the output of the phase comparator, and applying the output of the low-pass means to the voltage controlled oscillation means. .