JPS61112440A - Selective call receiver - Google Patents

Abstract

PURPOSE:To adjust automatically the sound volume of a selective call signal by adjusting the sound volume of the selective call signal generated from a speaker in multi-stage in response to the level of surrounding voice inputted from a microphone. CONSTITUTION:The surrounding voice signal S10 inputted from the microphone 10 is amplified by an amplifier 11, the level is stabilized by a diode 14 through an LPF12 and a capacitor 13 and rectified by a diode 15 and converted into a DC by an integration circuit comprising a resistor 16 and a capacitor 17 and inputted to each non-inverting input of three comparators 18-20. A power supply voltage Vc and voltage levels V1-V3 divided by four resistors 21-24 are inputted respectively to each inverting input of the comparators 18-20. Each output of the comparators 18-20 is inputted to a sete terminal S of FE25-27 as logical 1 or 0.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a selective call receiver (-), and particularly relates to a selective call receiver (2) that can perform audible notification by a speaker.

[Conventional technology]

Conventionally, in this type of selective call receiver, audible notification (
The second volume adjustment was predetermined using a manual switch, so the notification volume remained constant regardless of the surrounding sounds.

[Problem that the invention seeks to solve]

In the conventional selective call receiver described above, if the volume is initially fixed, for example, if the volume is set high, the sound will be abnormally loud in a quiet place (for example, a conference room). It has the disadvantage that it disturbs those who are present. On the other hand, if the volume is set low, it can be heard in relatively noisy surroundings (for example, a small room in a factory).

An object of the present invention is to provide a selective call receiver that can optimally determine the volume of an audible notification depending on surrounding sounds.

[Means for solving problems]

In order to achieve the above object, the present invention sets a plurality of stepwise reference levels in advance, and at the time of detecting surrounding sounds, the level of the sound and these plurality of stepwise reference levels are set. Based on the comparison, the volume level of the received audible notification of the own selective call signal is appropriately adjusted.

That is, the selective call receiver according to the present invention is a selective call receiver that generates an audible signal after receiving a selective call signal and detecting that it is its own. A detection/control circuit that outputs a control signal such that the above-mentioned audible signal is at an appropriate level (2) based on a comparison between the level and a plurality of preset stepwise reference levels; Adjust the level of (
It has two adjusting switch circuits.

〔Example〕

Hereinafter, two embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an embodiment of the present invention.

An antenna 1 receives a carrier wave modulated with a selective calling signal, that is, an input signal S1, and a radio section 2 receives the input signal S1.
is demodulated and sent to the decoder section 6 as a demodulated signal S2. The calling number storage section 4 is for storing the own calling number in advance, and the decoder section 6 compares the contents of the calling number storage section 4 with the input demodulated signal S2, and if they match, It is output to the speaker drive circuit 5 as a signal Sl. In addition, each timing signal (described later) is sent from the decoder section 6 to the detection/control circuit 6 (2).Speaker drive circuit 5
consists of a resistor R and a transistor Tr, and one end of a speaker 7 is connected to its output side. The other end of the speaker 7 is connected to a battery 9 via a switch circuit 8. The switch circuit 8 is for varying the current supplied to the speaker 7 in stages, and includes a first switch including a resistor RO.
a second path having the switch 8A in series and including the resistor Rm, and having the switch f8B in series and including the resistor R1! ! fI3 route and swing? The fourth containing only 8C
The paths are connected in parallel.

The detection/control circuit 6 detects the ambient sound 81G inputted from the microphone 10, and based on the comparison between the ambient sound 810 and the sulfur pressure level (described later), which has been divided into three levels C and 2, It functions to send a control signal S6 to the switch circuit 8 (2) so that the volume of the signal S3 emitted from the switch circuit 7 becomes appropriate (-).

Note that the reset signal fR8 belonging to the decoder section 6
T is for stopping the sound from the speaker 7.

Next (Second) Operation of the selective call receiver configured in this way (
Let me explain about two things.

Now, let's consider a case where it is used in a quiet place, such as a conference room. In this case, the sound 5l input from the microphone 10
(L becomes quite low in terms of level. Therefore, in the detection/control circuit 6, in advance, three levels (magnetic pressure level divided into two (described later), ambient sound 81 input from the microphone 10,
Based on the comparison with 0, the control signal S6 is outputted so as to reduce the volume from the speaker 7 with respect to the switch circuit 8 (2).In other words, the detection and control circuit 6 is 3 swings? 8A, 8B.

A signal S6 is sent to control the circuit 8C to maintain an open state. As a result, the volume heard through the speaker 7 becomes the lowest level.

On the other hand, when used in a relatively noisy place, the total resistance of the switch circuit 8 is minimized (2, that is, the switch f8C is closed (2), so that the sound can be heard from the speaker 7. You can adjust the volume to the highest level C:.

Next, the detection/control circuit 6 and the input circuit 8 shown in FIG. 81 will be explained in more detail with reference to FIG. 2, which shows an example of a specific circuit of the circuit 8.

Surrounding p signal SIO input from microphone 10
are amplified by an amplifier 11 and passed through a low-pass filter 12 . Capacitor 16? After the level is stabilized by the diode 14, the current is passed through the diode 15, converted into DC by an integrating circuit consisting of a resistor 16 and a capacitor 17, and input to the non-inverting input terminals of each of the three comparators 18, 19, and 20. Ru. The respective inverting input terminals of the comparators 18, 19 and 20 (the second one is connected to the source VC and the four resistors 21
The pressure levels V1, V2, divided by ~24
Turmeric comparator 18.1 into which each of Vs is input
The outputs of each of the flip-flops 25, 26, and 20 are output as logic "1' or "0", respectively, to the set terminals S (two inputs) of the flip-flops 25, 26, and 27.
．． 27, the power supply VB is connected to the reset terminal R of the inverter 2.
8, and the power supply VB and inverter 28
The connection point with this is grounded via a resistor 29. That is, when the power supply VB is not applied (second, the flip-flops 25, 26, and 27 are in the reset state, and when the power supply VB is applied, the outputs of the comparators 18, 19, and 20 are directly transferred to the flip-flops 25, 26, It is output to the output terminal Q of .27.The power supply v1 is the co/parator 1.
8.19.20 and is also the power source for the amplifier 11. Switch circuit 8 switch ″f8A, 8B
, 8C are flip-flops 27., 8C, respectively. “26.2
When the output of 5 is logic "1", C2 is closed.

Next, with reference to FIG.
It is assumed that VC is applied together with VC.

(1) First, when the surrounding audio signal 810 is lower than the voltage level V (St.≦v).

In this case, since the outputs of the comparators 18, 19, and 20 are all "O", these output signals are outputted to the output terminals QH of the flip-flops 25, 26, and 27, respectively.
As a result, switches 3A and 8B.

All 8C remain open. Therefore, the maximum resistance value of the switch circuit 8, that is, the resistance R
, so that the speaker 7 is connected to the battery 9.
The volume of the selective call signal that is heard is at the lowest level.

(2) Next, consider the case when Ml<Sto≦V.

In this case, only the output of the comparator 20 becomes 1",
This signal is passed through the flip-prop 27 to the swing f8A
close. Therefore, the resistance value of the switch circuit 8 is R
oRh/(Ro+RA), and in the case of (1) (compared to 2), the current supplied to the speaker 7 increases, so the volume heard from the speaker 7 becomes a lower level at the 2nd #.

(3) Further); Consider the case when Vz<Slo≦Vl.

In this case, the outputs of the comparators 20 and 19 become "1", so the swings f8A and 8B are closed.

Therefore, the resistance value of the switch circuit 8 is Ro-1'LA-
u17'(R6RA+RARB+RJIRO), and the current supplied to speaker 7 (2) further increases compared to case (2). Therefore, the volume heard from speaker 7 becomes the third lowest level.

(4) Finally, consider the case when vt<sto≦vc.

In this case, since the outputs of all the co/parators 18, 19.degree. 20 become "1", all the switches 8A, 8B, and Bc are closed. Therefore, the resistance value of the switch circuit 8 becomes zero (actually a very small value), and the current supplied to the speaker 7 becomes maximum.

Therefore, the volume heard from the speaker 7 is at the highest level.

As explained above (2), the volume of the selective call signal emitted from the speaker 7 can be adjusted in four levels (two) depending on the level of the surrounding sound SIG input from the microphone 10.

FIG. 6 shows a timing chart. (a) is an example of a selective call signal conveniently used in the selective call receiver of this embodiment. One frame is composed of 15 groups, and each group is a synchronization signal consisting of a pit synchronization code and a frame synchronization code. signal, and following this synchronization signal (consisting of eight self-selective calling signals 1 to 8). This is a timing signal for saving power (hereinafter referred to as a battery saving signal), and the "O" state represents a state in which the battery is disconnected from the circuit. (C) shows the timing of the sound of the speaker 7, (d) is the power supply V.

Indicates the timing of applying .

A selective call receiver normally operates a pantry saving signal at a certain period, but once it receives a synchronization signal, it thereafter operates a battery saving signal at a cycle of one frame in synchronization with the selective call signal train. Then, the time during which the battery saving signal is turned off, that is, “1
The state of 1.' is a little earlier than time t1 when the synchronization signal starts.
, and ends at the time t1 when the self-selection calling signal is received, in the example of FIG. 6, the self-selection calling signal 2 is received. At this time tm (2), the speaker 7 starts sounding, and the reset switch R8T (see Figure 1)
The sound continues until you operate it.

Further, the time for detecting the surrounding sound 810, in other words, the time for applying the power supply v1, starts at the same time as the time to when the battery saving signal rises, and ends at t2, which is slightly earlier than the time t1 when the battery saving signal falls. This means that the signal emitted from the speaker 7 is input into the microphone 10 (twice), and the surrounding sound S1.1;
This is to prevent the volume from the speaker 7 from reaching the highest level unrelatedly.

Note that each of the above-mentioned timing signals is generated from the decoder section 6.

In this embodiment, the volume heard from the speaker 7 is set to four levels, but it is clear that this can be easily adjusted to any level by appropriately configuring the switch circuit 8 and the detection/control circuit 6. Probably.

〔Effect of the invention〕

As explained above, the present invention has the effect of automatically adjusting the volume of the selective calling signal optimally according to the surrounding parties, and there is no need for the person carrying the receiver to operate the equivalent switch, etc., so it can be put into practical use. Kingship is very meaningful.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a selective calling receiver based on 8Al2 of the present invention, and FIG. 8
6(a) to (d) show timing t yards. 1... Antenna, 2... Radio section. 6... Decoder section, 4... Calling number storage section 25... Speaker drive circuit, 6... Detection/control circuit. 7...Speaker, 8...Switch circuit. 9...Battery, 10...Microphone. 18.19.20...Comparator. 21.22.26,24...Resistance. St + 82 + Sm + sa s Sso”
'Each signal. Vllr vc...power supply.

Claims (1)

[Claims] A selective calling receiver that generates an audible signal after receiving a selective calling signal and detecting that it is its own, detects the surrounding sound volume and uses the sound volume level and a plurality of preset detection and outputting a control signal that brings the audible signal to an appropriate level based on a stepwise comparison with a reference level;
A selective call receiver comprising: a control circuit; and a switch circuit that appropriately adjusts the level of the audible signal using the control signal.