JP2844981B2 - Radio selective call receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio selective calling receiver, and more particularly, to an improvement in a ringing sound generation circuit of a radio selective calling receiver.

[0002]

2. Description of the Related Art Conventionally, when a ringing tone is generated at the time of ringing of a radio selective calling receiver of this kind, a digital signal having a 1/0 pattern of a cycle corresponding to a ringing frequency is created and created by a logic circuit. The drive current and voltage are obtained based on the signal. The digital signal is amplified by a drive circuit, and sounding means such as an electromagnetic speaker and a piezoelectric buzzer are driven to obtain a sound. In this case, if the digital signal of the 1/0 pattern has a sufficient current and voltage, the signal may be directly applied to the sounding means.

By the way, this type of radio selective calling receiver is often equipped with a function of generating two kinds of sound pressures, a normal ringing tone and a weak ringing tone, so as to be compatible with various use environments. You can set the volume of your choice according to the usage environment. For this reason, in the drive circuit, a drive voltage and a current corresponding to a required sound pressure can be obtained. For example, a circuit that uses a plurality of drive circuits corresponding to the sound pressure and switches the volume by switching the drive circuits. The configuration is taken.

FIG. 5 shows an example of such a system, which comprises first and second drive circuits 22 and 23 in which the drive current and voltage of the sounding means are set according to the required sound pressure. 21 allows selection. The selected drive circuit receives the digital signal of the 1/0 pattern from the waveform output circuit 24 and drives the sounding means 25. Thus, two levels of volume can be realized by switching the switch 21.

[0005]

In such a conventional radio selective calling receiver, a plurality of drive circuits for outputting currents and voltages corresponding to different sound pressures are required, so that the circuit configuration becomes complicated. And there is a problem that it is disadvantageous in implementation. Also, when the digital signal of the 1/0 pattern is a current and a voltage sufficient to drive the sounding means, the sound pressure at the sounding means can be obtained even though the driving circuit is not necessary. There is also a problem that a drive circuit that outputs different currents and voltages is required to change the voltage. SUMMARY OF THE INVENTION It is an object of the present invention to provide a radio selective calling receiver which can generate sounds with different sound pressures without complicating the circuit configuration.

[0006]

SUMMARY OF THE INVENTION A radio selective calling receiver according to the present invention applies a voltage for causing a sounding means to sound.
One of the predetermined periods of the first terminal
A first circuit means for outputting a digital signal of a / 0 pattern, a second circuit means for outputting a digital signal having a phase inverted from that of the digital signal, and a second circuit means of the sounding means.
And a switching means for switching a signal to be output to a terminal of the digital signal between an inverted digital signal and a signal of a constant potential corresponding to a zero pattern of the digital signal. Preferably , the first circuit means for outputting the digital signal is a decoder of the receiver, the second circuit means for inverting the digital signal is an inverter, and the switching means is a circuit for selecting the output of the inverter and the ground potential. It is composed of a changeover switch applied to the second terminal. Or output digital signal of 1/0 pattern
The first circuit means for performing the processing is a decoder of the receiver.
The second circuit means for inverting the ground signal is turned off by an inverter.
Input means, input a digital signal to one input,
Select either power supply potential or ground potential for input
It consists of an AND gate to input. In addition, the radio of the present invention
A selective call receiver has a voltage applied between its two input terminals.
Radio selective call with ringing means for generating a ringing tone when
In the output receiver, of the two terminals of the sounding means,
A 1/0 pattern data of a predetermined cycle is applied to the first terminal.
First circuit means for outputting a digital signal;
Output a digital signal whose phase is inverted
Output to the second circuit means and the second terminal of the sounding means.
Signal into the inverted digital signal and a signal of a constant potential.
Switching means for switching.

[0007]

According to the present invention, by switching the changeover switch, the digital signal and its inverted signal are input to different terminals respectively by the sounding means, and the sounding means is made loud by a voltage twice as high as the digital signal. Drive with pressure. By switching the switch in reverse, the digital signal is directly input to the sounding means, and the sounding means is driven with a small sound pressure.

[0008]

Next, the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing an embodiment of the radio selective calling receiver according to the present invention. The radio signal received by the antenna 1 is amplified and demodulated by the receiving unit 2. The demodulated signal is subjected to waveform shaping in the waveform shaping circuit 3, and is converted into a 1/0 pattern digital signal readable by the decoder 4. The decoder 4 compares the data signal output from the waveform shaping circuit 3 with its own selected calling number stored in the P-ROM 5 in advance, and when these match, an alert signal voltage is generated by sounding means. The voltage is applied to both ends of the piezoelectric buzzer 6. The piezoelectric buzzer 6 is driven by the alert signal voltage, generates an alert sound, and notifies the radio selective call receiver carrier of the call. The clock 7 is used for generating a timing clock for synchronizing with the reception signal. The switch 8 is a reset switch for stopping the alert sound, 9 is a power switch, and 10 is a battery.

FIG. 1 shows an example of a drive circuit according to the present invention. It is composed of a part of the circuit of the decoder 4 shown in FIG.
The digital signal of the 1/0 pattern is applied to the first terminal 6A of the piezoelectric buzzer 6. The digital signal is applied to the second terminal 6B of the piezoelectric buzzer 6 via the inverter 11 and the changeover switch 12. The inverter 11 inverts the phase of the digital signal applied to the second terminal 6B. Also, the changeover switch 22
Changes the output of the inverter 11 to the second position in the case of the N position.
The voltage is applied to the terminal 6B, and in the case of the M position, the second terminal 6B is grounded.

According to this configuration, the user of the radio selective calling receiver switches the changeover switch 12 between the N position and the M position to select the normal ringing tone or the weak ringing tone. That is, when switching to the N position, as shown in FIG. 3, a 1/0 digital signal shown in (a) is applied to the first terminal 6A of the piezoelectric buzzer 6, and at the same time, to the second terminal 6B. 1/0 digital shown in (b), in which the digital signal is inverted by the inverter 11, is applied. As a result, the first and second terminals 6A, 6A
As shown in (c), a voltage twice as high as the digital signal output from the decoder 3 is applied between B. As a result, the ringing sound of the piezoelectric buzzer 6 increases.

On the other hand, when the changeover switch 12 is switched to the M position, a 1/0 pattern digital signal is applied only to the first terminal 6A of the piezoelectric buzzer 6A, and the second signal is applied to the second terminal 6A.
The terminal 6B is at the ground potential (= logic "0"). Therefore, since the voltage of the digital signal output from the decoder 3 is applied to the piezoelectric buzzer 6 as it is, the ringing tone is reduced. The sound pressure is reduced by about 6 dB as compared with the N position. Therefore, by switching the changeover switch 12, two different sound pressures can be called by one drive circuit, and the circuit configuration can be simplified.

FIG. 4 shows another example of the drive circuit. A digital signal of a 1/0 pattern is applied to the second terminal 6B of the piezoelectric buzzer 6 through a logic circuit composed of an inverter 11 and an AND gate 13. I have. And And 1
The power supply potential or the ground potential is selected and input to the other input 3 by the changeover switch 12.

In this configuration, when the changeover switch 12 is set to the N position, a logical 1 signal is input to the other input of the AND gate 13. Therefore, the signal input to one input of the AND gate 13, that is, the inverter 1
The digital signal of the 1/0 pattern whose phase is inverted through 1 passes through the AND gate 13 as it is and is applied to the second terminal 6B of the piezoelectric buzzer 6. As a result, FIG.
As in the case shown in (c), a voltage twice the digital signal is applied to the piezoelectric buzzer 6, and the piezoelectric buzzer 6 generates a loud ringing tone.

On the other hand, when the changeover switch 12 is set to the M position, a signal of logic 0 is inputted to the other input of the AND gate 13, so that the AND gate 13 is turned off. Therefore, the second terminal 6B of the piezoelectric buzzer 6 has a low level potential, and the digital signal voltage is applied to the piezoelectric buzzer 6 as it is. Thus, the ringing sound of the piezoelectric buzzer 6 is reduced.

[0015]

As described above, the present invention provides a sounding means.
A case of applying the digital signal and the inverted signal between two terminals, digital signal and the digital signal
Switching between the case of applying a signal of a constant potential corresponding to the zero pattern and the case where the ringing tone of the ringing means is switched without providing a plurality of drive circuits in order to obtain different drive currents / voltages Therefore, there is an effect that the circuit configuration can be simplified and mounting can be performed advantageously. Further, in the present invention, since a circuit for driving the sounding means can be constituted by a logic circuit, the circuit can be built in the decoder IC, so that the circuit can be integrated and the mounting efficiency in the receiver can be improved. .

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a driving circuit of a sounding means according to the present invention.

FIG. 2 is a block diagram showing the overall configuration of one embodiment of the present invention.

FIG. 3 is a diagram showing a waveform of a digital signal applied to a sounding means.

FIG. 4 is a circuit diagram of another example of the drive circuit according to the present invention.

FIG. 5 is a block diagram showing an example of a driving circuit in a conventional receiver.

[Explanation of symbols]

 2 Receiving part 3 Waveform forming circuit 4 Decoder 5 P-ROM 6 Sounding means (piezoelectric buzzer) 11 Inverter 12 Changeover switch 13 AND gate

Claims (4)

(57) [Claims] 1. A radio selective calling receiver comprising a ringing means for generating a ringing sound when a voltage is applied between two input terminals, wherein a first one of the two terminals of the ringing means is provided.
A first circuit means for outputting a digital signal having a 1/0 pattern of a predetermined cycle to a terminal of the second circuit, a second circuit means for outputting a digital signal whose phase is inverted with respect to the digital signal, and the sounding means Switching means for switching a signal to be output to the second terminal between the inverted digital signal and a signal having a constant potential corresponding to a zero pattern of the digital signal. 2. The method according to claim 1, wherein said first circuit means for outputting a digital signal of a 1/0 pattern is a decoder of a receiver, said second circuit means for inverting said digital signal is an inverter, and said switching means is 2. The radio selective call receiver according to claim 1, wherein the switch is a changeover switch that selects an output of the inverter and a ground potential and applies the selected output to the second terminal. 3. A 1/0 pattern digital signal is output.
The first circuit means is a decoder of a receiver,
The second circuit means for inverting the digital signal of
A switching unit, wherein the switching means is connected to one of the inputs.
Digital signal, and supply potential and ground potential to the other input.
AND gate to select and enter one of
The radio selective call reception according to claim 1, wherein
Machine. 4. When a voltage is applied between two input terminals.
Selective ringing receiver provided with a ringing means for generating a ringing tone when a call is made
In the transceiver, of the two terminals of the sounding means,
1/0 pattern digit of the predetermined cycle
First circuit means for outputting a digital signal,
A second signal for outputting a digital signal whose phase is inverted from that of the signal
Circuit means and a signal to be output to a second terminal of said sounding means
Into the inverted digital signal and a signal of a constant potential.
Switching means for switching the call
Out receiver.