JPH04213925A - Radio selective calling receiver - Google Patents

Abstract

PURPOSE:To optimize the reception state of an antenna without being effected of a nonlinear characteristic of a variable capacitor and the dispersion in the characteristic of the variable capacitor and a voltage controlled oscillator by selecting variable capacitors. CONSTITUTION:A variable capacitor 14 and capacitors 13,15 having a circuit constant in tuning with a radio signal of each channel to be received are provided to an antenna circuit 2 and diodes 17,18 are employed to select the relevant variable capacitor 14 and capacitors 13,15 based on a tuning control signal of a control section 4 thereby setting the antenna reception state.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of Industrial Application The present invention is applied to an antenna circuit of a radio selective calling receiver. In particular, the present invention relates to a means for tuning an antenna circuit of a multi-channel radio selective calling receiver.

0002

2. Description of the Related Art FIG. 6 is a block diagram of a conventional radio selective call receiver. FIG. 7 is a circuit diagram of an antenna section of a conventional radio selective calling receiver. FIG. 8 is a diagram showing the relationship between the channels of a conventional radio selective calling receiver and the output voltage of a voltage controlled oscillator. FIG. 9 is a diagram showing voltage characteristics of a voltage controlled oscillator of a conventional radio selective calling receiver. Figure 1
0 is a diagram showing voltage characteristics of a varicap of a conventional radio selective calling receiver. FIG. 11 is a diagram showing antenna tuning characteristics of a conventional radio selective calling receiver.

[0003] Conventionally, radio selective calling receivers have received a single frequency, but in recent years, the functionality has become more sophisticated, such as a multi-channel system using a plurality of crystals or a multi-channel system using a synthesizer system. In particular, in a multi-channel system using a synthesizer, in order to reduce the sensitivity difference between channels, the frequency at which the antenna tuning frequency is received by the varicap is always adjusted using the voltage input to the voltage controlled oscillator of the synthesizer (output of the low-pass filter). I tried to get it close to the best sensitivity. (For example, Japanese Patent Publication No. 62-13129).

FIG. 6 shows an example of a conventional synthesizer type receiver. In FIG. 6, the antenna circuit 2A is composed of a circuit for tuning with the antenna 1 and matching with the radio section 3, and a detailed circuit example is shown in FIG. The antenna section 50 is composed of a variable capacitor 31, a capacitor 32, a varicap 33 for tuning with the antenna 1, and a coupling capacitor 16 for matching with the next stage.
The radio signal obtained at A is sent from the terminal 23 to the radio section 3. A voltage applied to the voltage controlled oscillator 6 is applied to the terminal 35.

The above operation is illustrated in FIGS. 8(a) and 8(b).
) is shown. Figure 8(b) shows channel fL (low frequency), channel f0 (center frequency), and channel fH.
Figure 8(a) shows how the output voltage of the voltage controlled oscillator changes at high frequencies. Figure 8(a) shows the changes in antenna tuning characteristics for each channel fL, f0, fH. . Figure 8(a) and Figure 8(b)
The antenna tuning frequency is changed according to the output voltage of the voltage controlled oscillator to reduce sensitivity deterioration.

[0006]

[Problems to be Solved by the Invention] However, in such a conventional radio selective calling receiver, the antenna circuit has the voltage characteristic Δf/ΔV of the voltage controlled oscillator and the voltage characteristic Δf/ΔV shown in FIG.
Since the voltage characteristics ΔC/ΔV of the varicap shown in 0 do not match, there is a drawback that it is not possible to achieve the best sensitivity in all channels (frequencies) due to the influence of the varicap during mass production.

[0007] Also, the antenna tuning characteristics in this case are shown in Figure 1.
1, and the channels fL and f0 are optimal, but the channel fH has the disadvantage that it deviates from the tuning point and cannot have uniform characteristics in the necessary frequency band.

The present invention solves the above-mentioned drawbacks, and makes it possible to optimize the antenna reception state without being affected by variations in the characteristics of the voltage controlled oscillator, variations in the characteristics of the varicap, and nonlinear characteristics. The purpose of the present invention is to provide a wireless selective calling receiver that can perform the following functions.

[0009]

[Means for Solving the Problems] The present invention provides an antenna section that receives radio signals of multiple channels, a radio section that converts and demodulates the output signal of this antenna section to an intermediate frequency, and a local oscillation signal that is transmitted to the radio section. and a control unit that controls the local oscillation unit to tune to one of the radio signals of the plurality of channels, and the antenna unit receives the radio signals of the plurality of channels. and an antenna circuit that tunes to one of the received signals of the plurality of channels output from the antenna based on an input tuning control signal and provides the tuned radio signal to the radio unit. In the apparatus, the control unit includes means for applying a tuning control signal corresponding to a channel to be received to the antenna circuit, and the antenna circuit includes a plurality of circuit elements having circuit constants tuned to the radio signals of each channel. , further comprising a setting means for selecting and setting a circuit element having a circuit constant tuned to a radio signal of a channel to be received based on the tuning control signal.

Further, in the present invention, the circuit element may have a capacitive circuit constant, and the setting means may be a diode that selects the corresponding circuit element based on the tuning control signal and connects it to the antenna. can.

[0011]

[Operation] The control section provides the antenna circuit with a tuning control signal corresponding to the channel to be received. The antenna circuit includes a plurality of circuit elements having circuit constants tuned to the radio signal of each channel, and the setting means selects the circuit element having the circuit constant tuned to the radio signal of the channel to be received based on the tuning control signal. Set. Further, the circuit element has a capacitive circuit constant, and the setting means is a diode that selects the corresponding circuit element based on the tuning control signal and connects it to the antenna.

[0012] As described above, the antenna reception state can be brought to an optimum state without being affected by variations in the characteristics of the voltage controlled oscillator, variations in the characteristics of the varicap, and nonlinear characteristics.

[0013]

Embodiments Examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a wireless selective call receiver according to an embodiment of the present invention. FIG. 2 is a circuit diagram of the antenna section of the radio selective calling receiver of the present invention.

In FIGS. 1 and 2, the radio selective calling receiver includes an antenna section 50 that receives radio signals of a plurality of channels, a radio section 3 that converts and demodulates the output signal of the antenna section 50 to an intermediate frequency, and a radio A synthesizer section 11 serves as a local oscillation means for supplying a local oscillation signal to the section 3, a control section 4 controls the synthesizer section 11 to tune to one of the radio signals of a plurality of channels, and a control section 4 serves as a local oscillation means for supplying a local oscillation signal to the demodulated radio signal. The synthesizer section 11 includes a notification section 5 that outputs,
Voltage controlled oscillator 6, low pass filter 7, frequency divider 8
, a phase comparator 9, and a reference signal oscillator 10;
The antenna circuit 2 is tuned to one of the received signals of a plurality of channels outputted by the antenna circuit 2 and provides the tuned radio signal to the radio section 3.

The feature of the present invention is that the control unit 4 includes means for providing the antenna circuit 2 with a tuning control signal corresponding to the channel to be received;
A plurality of circuit elements having circuit constants tuned to the radio signal of each channel, and a setting means for selecting and setting the circuit element having the circuit constant tuned to the radio signal of the channel to be received based on the tuning control signal. It is in.

Further, the circuit elements include variable capacitors 14 each having a capacitive circuit constant connected to the antenna 1.
, and capacitors 13 and 15, and the setting means includes diodes 17 and 18 which are connected to the capacitors 13 and 15, respectively, and which select the corresponding circuit element based on the tuning control signal and connect it to the antenna 1.

Furthermore, the antenna section 50 includes a coupling capacitor 16 and a terminal 2 that connect the antenna 1 and the radio section 3.
3, a control terminal A inserted between the control section 4 and the anode of the diode 17, a resistor 20 and a choke 19, a control terminal B inserted between the control section 4 and the anode of the diode 18, and a resistor 22. and a choke 21.

The operation of the radio selective calling receiver having such a configuration will be explained.

FIG. 3 is a diagram showing the operation of the antenna circuit of the radio selective calling receiver according to the present invention using a spectrum on the frequency axis. FIG. 4 is a flowchart showing reception frequency designation by the control section of the radio selective calling receiver of the present invention. FIG. 5 is a diagram showing antenna tuning characteristics at steps S1 and S2 in the flowchart shown in FIG. 4 of the radio selective calling receiver of the present invention. Table 1 is a table showing the relationship between the tuning control signal input to the control terminal of the radio selective calling receiver of the present invention and the tuning channel.

[Table 1]

In FIG. 1, the control section 4 specifies a reception channel (frequency specification) for the frequency divider 8 of the synthesizer section 11, and at the same time, in order to optimize the tuning of the antenna circuit 2, the control section 4 specifies the antenna corresponding to the frequency. Also specifies the selection of circuit constants.

FIG. 2 shows an example in which the antenna 1 and antenna circuit 2 shown in FIG. 1 are constructed using specific circuits. In this example it is possible to select three tuning frequencies. The tuning frequency of the antenna circuit 2 is determined by the combination of the antenna 1, the variable capacitor 14, and the capacitors 13 and 15. In this case, switch diodes 18, 17
Three frequencies can be selected by switching. The table shows the relationship between the control signals applied to the control terminals A and B shown in FIG. 2 and the tuning frequency.

FIG. 3 shows the operation shown in the table as a spectrum on the frequency axis.
The tuning characteristics in the case of L are shown in 26. The case of the channel f0 of the center frequency is shown in 27, and the channel fH of the higher frequency is shown in 28.

FIG. 4 shows the flow of control signals from the control section 4, and FIG. 5 is a diagram showing the tuning characteristics of the antenna circuit 2 corresponding to the control signals. This flow shows the situation when the control unit 4 changes from the center frequency channel f0 to the lower frequency channel fL.

As described above, it is possible to optimize the antenna tuning characteristics depending on the reception frequency.

[0025]

[Effects of the Invention] As explained above, the present invention is capable of optimizing antenna reception conditions without being affected by variations in characteristics of voltage controlled oscillators, variations in characteristics of varicaps, and nonlinear characteristics. It has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wireless selective call receiver according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the antenna section of the radio selective calling receiver of the present invention.

FIG. 3 is a diagram showing the operation of the antenna circuit of the radio selective calling receiver according to the present invention according to Table 1 using a spectrum on the frequency axis.

FIG. 4 is a flowchart showing reception frequency designation of the control unit of the wireless selective calling receiver of the present invention.

FIG. 5 is a diagram showing antenna tuning characteristics at steps S1 and S2 in the flowchart shown in FIG. 4 of the radio selective calling receiver of the present invention.

FIG. 6 is a block diagram of a conventional wireless selective call receiver.

FIG. 7 is a circuit diagram of an antenna section of a conventional radio selective calling receiver.

FIG. 8 is a diagram showing the relationship between the channels of a conventional radio selective call receiver and the output voltage of a voltage controlled oscillator.

FIG. 9 is a diagram showing voltage characteristics of a pressure-controlled oscillator of a conventional radio selective calling receiver.

FIG. 10 is a diagram showing voltage characteristics of a varicap of a conventional radio selective calling receiver.

FIG. 11 is a diagram showing antenna tuning characteristics of a conventional wireless selective call receiver.

[Explanation of symbols]

1 Antenna 2, 2A antenna circuit 3 Wireless section 4, 4A Control section 5　Notification Department 6 Voltage controlled oscillator 7 Low pass filter 8 Frequency divider 9 Phase comparator 10 Reference signal oscillator 11 Synthesizer section 13, 15, 32 capacitor 14, 31 Variable capacitor 16 Coupling capacitor 17, 18 Diode 19, 21 Chalk 20, 22, 34 resistance 23, 35 terminal 33 Varicap 50, 50A antenna part A, B Control terminal

Claims (2)

[Claims] 1. An antenna section that receives radio signals of multiple channels, a radio section that converts the output signal of the antenna section to an intermediate frequency and demodulates it, a local oscillation means that supplies a local oscillation signal to the radio section, and the above-mentioned. a control section that controls the local oscillation means to tune to one of the radio signals of the plurality of channels; the antenna section includes an antenna that receives the radio signals of the plurality of channels; and an antenna circuit that tunes to one of the received signals of the plurality of channels outputted from the antenna based on the signal and provides the tuned radio signal to the radio unit, wherein the control unit the antenna circuit includes a plurality of circuit elements having circuit constants that tune to the radio signal of each channel, and a means for providing a tuning control signal corresponding to the channel to be received based on the tuning control signal. 1. A radio selective call receiver comprising a setting means for selecting and setting a circuit element having a circuit constant tuned to a radio signal of a desired channel. 2. The radio according to claim 1, wherein the circuit element has a capacitive circuit constant, and the setting means is a diode that selects a corresponding circuit element based on the tuning control signal and connects it to the antenna. Selective call receiver.