JP2002232307A - Method of controlling squelch of radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling the squelch of radio equipment by which the reception quality of the equipment can be improved. SOLUTION: The intensities of received signals is checked at fixed periods and, when the intensity of lately checked received signals is higher than a squelch open level and the intensity of last checked received signals, a timer of which the measuring time is longer than the fixed period is reset to a starting state. Then whether or not the measuring time of the timer expires is discriminated and, in addition, whether or not the intensity of received signals is lower than the squelch open level is discriminated. When it is discriminated that the intensity of received signals is lower than the squelch open level and, at the same time, the measuring time of the timer expires, the squelch of the radio equipment is closed. In the other states, the squelch is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squelch control method for a wireless device.

[0002]

2. Description of the Related Art A radio apparatus is provided with a squelch circuit.
This squelch circuit is a circuit that mutes the received voice (closes the squelch) when the received signal is weak or when there is no received signal so that noise cannot be heard from the speaker.

FIG. 6 shows the relationship between the conventional radio receiver signal strength and microcomputer squelch control. Thus, conventionally,
The microcomputer closes the squelch and mutes the received voice when the received signal strength falls below the “squelch release level−hysteresis” set for the wireless device even for a moment.

[0004]

However, as described above, in the method of closing the squelch and muting the received voice when the received signal intensity falls below the squelch open level even for a moment, the communication partner moves while moving with a vehicle-mounted radio or the like. When listening to the sound, if the signal strength falls momentarily below the squelch open level due to fading caused by surrounding conditions such as the shadow of a building, the microcomputer will mute the sound each time, and communication will not be established ( I don't know if you're talking about it), or the sound is often interrupted and uncomfortable.

[0005] The present invention has been made in view of the above points,
An object of the present invention is to provide a squelch control method for a wireless device that can improve reception quality.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the above object, a squelch control method for a wireless device according to the present invention checks a received signal strength at a constant period, and determines whether the signal strength checked this time is squelch. First means for resetting a timer having a measurement time longer than the predetermined period to a start state each time the level is equal to or higher than the release level and equal to or higher than the level checked last time; and the timer controlled by the first means. A second means for determining whether the measured time has expired, a third means for determining whether the received signal strength is below the squelch release level, and a third means for determining whether the received signal strength is less than the squelch release level. The state below the level is determined, and at the same time, the squelch is closed when the second unit determines that the measurement time of the timer has expired, and the squelch is opened in other states. Characterized by comprising fourth and means.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a squelch control method for a radio according to the present invention. FIG. 2 is a block diagram showing a wireless device provided with an embodiment of the squelch control method of the present invention. In this block diagram, 11 is an antenna, 12 is a receiving circuit,
The receiving circuit 12 selects, amplifies, and detects a received signal. Then, the audio signal output from the receiving circuit 12 by the detection is supplied to the speaker 16 via the filter 13, the mute switch 14, and the amplifier 15, and is converted into audio. Also, a signal for detecting the received signal strength, specifically, a squelch detection voltage and an RSSI (FM
Either or both of the limiter saturation state display voltage) is output from the receiving circuit 12, and this signal is output to the A / D converter 1
After being A / D-converted in 7, it is supplied to a CPU (microcomputer) 18. Then, the received signal strength is detected from the supplied signal, and the CPU 18 controls the mute switch 14.
And squelch control is performed. Although not shown, the CPU 18 is provided with a squelch close (Close) timer. Further, the CPU 18 is connected to a memory 19 for storing a previous signal level described later.

In the above-mentioned radio, the squelch control is C
This is performed by the PU 18 as follows. (1) FIG. 1 is a flowchart showing a squelch control method. FIG. 3 is a diagram showing the relationship between the change in the received signal strength and the timing at which the CPU 18 checks it. C
The PU 18 takes in the output value of the A / D converter 17 as shown in step S1 of FIG. 1 and reduces the received signal strength at a certain fixed period (for example, 3 mSec) as shown from the point A to the point M in FIG. To check. (2) When the signal strength X checked this time is equal to or higher than the squelch release level Z (step S2 in FIG. 1) and equal to or higher than the level Y checked last time (step S3 in FIG. 1), the CPU 18 The provided squelch close timer (not shown) (measurement time is longer than the predetermined period, for example, 5 mSec) is reset to the start state (step S4 in FIG. 1). (3) Therefore, in FIG. 3, point A: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point B: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point C: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point D: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point E: Since the level is below the level of point D, the squelch close timer is not reset to the start state. Point F: Since the level is below the level of the point E, the squelch close timer is not reset to the start state. Point G: The squelch close timer is not reset to the start state because it is below the squelch release level. Point H: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point I: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point J: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point K: Since the above condition is satisfied, the squelch close timer is reset to the start state. Point L: Since the level is below the level at point K, the squelch close timer is not reset to the start state. Point M: Since the level is below the level of the point L, the squelch close timer is not reset to the start state. (4) On the other hand, the CPU 18 determines whether the received signal strength X is lower than the squelch open level Z (step S2 in FIG. 1). (5) Further, the CPU 18 determines whether the measurement time of the squelch close timer has expired (step S in FIG. 1).
5). (6) Then, if it is determined in step S2 that the received signal strength X has fallen below the squelch release level Z, and at the same time it is determined in step S5 that the measurement time of the squelch close timer has expired, the CPU 18 sets the mute switch 14 to OFF. Is turned off and the squelch is closed (step S in FIG. 1).
6) Mute the received voice. (7) In other states, that is, when the squelch close timer is measuring time or when the received signal strength X is equal to or higher than the squelch release level Z, the CPU 18 turns on the mute switch 14 to open the squelch (see FIG. 1). Step S
7) The received sound is reproduced from the speaker 16.

In FIG. 1, a step S8 sets the current signal level X as the previous signal level Y in the memory 19.
This is a step of storing the information.

As described above, in the above-mentioned radio, squelch is controlled using the strength of the received signal and the timer. Therefore, the following effects can be obtained. (1) Even if the received signal strength falls momentarily below the squelch open level, the squelch does not close due to the operation of the squelch close timer, so that the voice of the other party can be heard. (2) As shown in FIG. 4, when the signal level is near the squelch open level, the squelch close timer can prevent squelch flapping. (3) As shown in FIG. 5, since the squelch close timer measures the time from when the received signal level starts to decrease, the squelch can be closed immediately when the signal level gradually falls below the squelch open level. . (4) The reception quality can be improved by the above (1) to (3).

[0011]

As described above in detail, according to the squelch control method for a wireless device of the present invention, the reception quality can be improved by controlling the squelch by the strength of the received signal and the timer.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of a squelch control method for a wireless device according to the present invention.

FIG. 2 is a block diagram showing a wireless device including an embodiment of a squelch control method for a wireless device according to the present invention.

FIG. 3 is a waveform chart for explaining an embodiment of a squelch control method for a wireless device according to the present invention.

FIG. 4 is a waveform chart for explaining the effect of the squelch control method for a wireless device according to the present invention.

FIG. 5 is a waveform chart for explaining the effect of the squelch control method for a wireless device according to the present invention.

FIG. 6 is a waveform diagram showing a relationship between a conventional wireless device reception signal strength and microcomputer squelch control.

[Explanation of symbols]

 14 Mute switch 18 CPU 19 Memory

Continued on the front page F term (reference) 5K052 AA01 BB08 EE13 FF12 GG02 GG54 GG57 5K067 AA02 AA23 DD44 FF35 HH22 KK00

Claims (1)

[Claims] 1. A method for checking a received signal strength at regular intervals,
When the signal strength checked this time is equal to or higher than the squelch open level and equal to or higher than the level checked last time, a first means for resetting a timer having a measurement time longer than the predetermined cycle to a start state each time; A second means for determining whether the timer controlled by the means has expired, a third means for determining whether the received signal strength has fallen below a squelch open level, and the third means. The state where the received signal strength is below the squelch release level is determined at the same time. At the same time, the squelch is closed when the expiration of the measurement time of the timer is determined by the second means, and the squelch is opened in other states. And a means for controlling squelch of a wireless device.