JPH06120861A - Cordless telephone set - Google Patents

Abstract

PURPOSE:To provide a cordless telephone set which can shorten the checking time and also can simplify the constitution by automating the offset control of an RF module at the time of a performance set. CONSTITUTION:A microcomputer 31 previously stores the standard offset value of an RF module 4 in an E<2>PROM 30. In a performance test mode, the microcomputer 31 sets the reception intensity of the module 4 as the offset value via an A/D converter 6 and defines the difference between the offset value and the standard offset value as the standard offset. Then the the received signal of the antenna having higher reception intensity is always selected in a normal mode based on the difference between the reception intensity of the module 4 and the standard reception intensity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone set, and more particularly to a cordless telephone set in which manufactured cordless telephone sets automatically have the same reception intensity when receiving radio waves under the same conditions in the same environment.

[0002]

2. Description of the Related Art Generally, in a cordless telephone, the incident angle of incoming radio waves is not constant but constantly fluctuates. For this reason, it is called a tie diversity antenna system that always induces the maximum voltage in the antenna in response to the incident direction, and cordless telephones also use two antennas arranged differently according to such a system. There is. Before shipment, a cordless telephone (hereinafter simply referred to as a telephone) uses a radio wave generator at a factory or the like to radiate a radio wave with a certain transmission intensity so that the minimum reception intensity is that the user can hear as a sound. do.

This is because a telephone generally detects a target signal from at least an analog high frequency electric wave,
An RF module that obtains a baseband signal and an analog reception intensity signal (also referred to as an RSSI signal) is provided, and each circuit performs a predetermined operation when an AC signal is input. Therefore, during the performance test, the performance test is performed using a radio wave generator. Also, the receiver has a reception sensitivity, which is one of the performances of a radio receiver, for example, how much output voltage can be obtained by giving a radio frequency input voltage. The sensitivity makes the rate of change in the output voltage with respect to the input voltage constant.

Therefore, the reason why the manufactured telephones have the same reception strength under the same radio wave condition in the same environment is, for example, if the strength of the antenna is 100 mV level, it is 1V.
The reception strength is set so that all the manufactured telephones have such reception strength. Such a telephone will be described below.

FIG. 5 is a block diagram showing a performance test of a conventional cordless telephone. In the figure, 1 is an antenna,
Reference numeral 2 is an antenna, and 3 is a selection circuit for selecting a high frequency reception signal of either the antenna 1 or the antenna 2 based on a selection signal. This selection circuit switches the connection contact with the antenna to switch the antenna 1 or the antenna 2, for example.
Either of the high frequency reception signals (hereinafter referred to as the reception signal) is selected based on the selection signal. Reference numeral 4 denotes an RF module which detects a reception signal from the antenna 1 or the antenna 2 and outputs it as a baseband signal, and calculates and outputs the reception intensity of the reception signal. Reference numeral 5 is a level adjustment circuit that corrects the level of the reception intensity from the RF module 4 based on a preset attenuation amount, and an attenuator or the like is used. In general, when a plurality of telephones are manufactured, the level adjusting circuit 5 has to make the receiving intensities of the plurality of telephones the same when radio waves under the same conditions are radiated.

However, in general, the RF module circuit 4
Generally, the offset values are different from each other due to the manufacturing error of the IC inside the device. Therefore, even if the reception intensity is set to be constant, if there are manufacturing errors and the offset values are different, when the radio waves under the same conditions are received, the reception intensity from the RF module circuit 4 is different from each other. . Therefore, when a radio wave under the same conditions is received in the same environment, the operator changes the resistance and the like to set the attenuation amount in consideration of the offset value. Reference numeral 6 is an A / D converter for converting the reception intensity signal from the reception level adjusting circuit 5 into a digital signal.

Reference numeral 7 is a microcomputer. The microcomputer 7 compares the reception intensity data from the A / D converter 6 with a preset minimum reference intensity level in actual use, and outputs a selection signal based on the comparison result to the selection circuit 3. . 10 is a baseband processing unit, 1
1 is a microphone and 12 is a speaker. Reference numeral 13 is a radio wave generator arranged at a predetermined distance from the telephone and emitting a radio wave having a constant transmission intensity, and 14 is a measuring instrument for measuring a reception intensity signal from the level adjusting circuit 5.

A case of performing a performance test with the measurement system configured as described above will be described. In this case, it is assumed that a plurality of telephones are adjusted in the factory, the transmission intensity of the radio waves emitted from the radio wave generator 13 is constant, and the distance between the telephones and the radio wave generator 13 is constant. Furthermore, the measuring device 14
The probe is connected to the output of the RF module 4 and the output of the level adjusting circuit 5. In such a state, when the selection circuit 3 is selecting a reception signal on the antenna 1 side and a radio wave is emitted from the radio wave generation device 13, the reception intensity obtained by the RF module 4 is output from the level adjustment circuit 5. The received intensity signal of is measured by the measuring device 14. The reception intensity from the RF module 4 at the time of this test is determined as the offset value of the RF module.

Then, the operator has adjusted the level adjusting circuit 5 so that the measured offset value becomes a predetermined standard offset value. Next, when the performance test is completed, the operator enters the actual use mode, and the microcomputer 7 compares the received intensity data from the A / D converter 6 with the preset reference intensity level during use, In the following cases, a selection signal for selecting the reception signal on the antenna 2 side is output to the selection circuit 3.

If the selection signal is a selection signal for selecting the reception signal on the antenna 2 side, the selection circuit 3 selects the reception signal on the antenna 2 side and outputs it to the RF module 4. That is, the microcomputer 5 checks the level of the reception intensity data after A / D conversion, and when the reception intensity is lower than the reference reception intensity value, switches to the other antenna so that the reception intensity is always at a high level. I was trying to keep it.

[0011]

As described above, the conventional telephone is equipped with the RF module which receives at least a high frequency reception signal and obtains the reception intensity of the reception signal.
Therefore, the offset value of the RF module is different for each telephone, and even if the radio waves under the same conditions are received in the same environment, the reception intensities are different.

Therefore, conventionally, a level adjusting circuit for adjusting the level of the reception intensity signal from the RF module is provided,
Under the same environment and under the same conditions, the level is adjusted so that the reception intensities of a plurality of manufactured telephones are the same, and the reception intensity is set in consideration of the offset value of the RF module. This adjustment is carried out for each telephone manufactured by the worker before shipment. In other words, the worker has to manually adjust the level of each telephone before shipping, which causes a problem that it takes a lot of time for the adjustment.

Further, since a level adjusting circuit for making the reception intensity levels the same is required, there is a problem that the structure of the telephone becomes complicated and large. The present invention has been made to solve the above problems, and it is an object of the present invention to obtain a telephone having a simple configuration while automating the offset adjustment of the RF module at the time of performance test, shortening the inspection time, and reducing the inspection time.

[0014]

A cordless telephone according to the present invention includes a selection circuit for selecting a high frequency reception signal received by one of antennas arranged at different positions and outputting the selected reception signal. The RF module that inputs the high frequency reception signal and calculates and outputs at least the reception intensity of the high frequency reception signal, and when the performance test is informed, the reception intensity from the RF module is set as the offset value of the RF module. A reference offset value calculation means for storing a difference between the offset value and a standard offset value stored in advance as a reference offset value,
When the performance test is canceled, every time the reception intensity is output from the RF module, the reception intensity is corrected by the reception intensity correction unit that corrects the reception intensity based on the reference offset value, and the reception intensity calculation unit. And a reception signal selecting means for causing the selection circuit to select an antenna that obtains a high-frequency reception signal that is always equal to or higher than the reference reception intensity, which is compared with the reference reception intensity stored in advance.

Further, the reference offset value calculation means, the reception intensity correction means and the reception reception signal selection means are implemented by a microcomputer.

[0016]

In the present invention, when the RF module detects the reception intensity of the high frequency reception signal of the antenna selected by the selection circuit during the performance test to obtain the reception intensity, the reference offset value calculating means of the microcomputer is operated. The reception intensity from the RF module is used as an offset value, and the difference between the offset value and the standard offset value stored in advance is stored as the reference offset value.

Next, when the performance test is canceled, the reception intensity correction means of the microcomputer corrects the reception intensity based on the reference offset value every time the reception intensity is output from the RF module, and the reception intensity is received. The signal selection means compares the corrected reception intensity with the reference reception intensity stored in advance, and causes the selection circuit to select an antenna that obtains a high frequency reception signal that is always equal to or higher than the reference reception intensity.

[0018]

1 is a conceptual diagram showing the configuration of a cordless telephone according to the present invention. In the figure, 1 to 12 are the same as above. Reference numeral 20 is a reference offset value calculation means.
When the reference offset value calculation means 20 is informed that the performance test is performed, the reception intensity from the RF module 4 is set as the offset value of the RF module 4, and the difference between the offset value and the standard offset value stored in advance is calculated. It is stored as a reference offset value.

Reference numeral 21 is a reception strength correction means. When the performance test is canceled, the reception intensity correction means 21 corrects the reception intensity based on the reference offset value every time the reception intensity is output from the RF module 4. Reference numeral 22 is a reception signal selection means. The reception signal selection means 22 compares the reception intensity corrected by the reception intensity correction means 21 with the reference reception intensity stored in advance, and selects an antenna that obtains a high frequency reception signal that is always equal to or higher than the reference reception intensity in the selection circuit. Let A specific example of the above cordless telephone will be described below.

FIG. 2 is a schematic configuration diagram of a specific example of the cordless telephone of the present invention. In the figure, 1 to 6 are the same as those in FIG. 30 is an E ² PROM (elec
trially erasable program
Able ROM). This E ² PROM 30 is
At least the abbreviated telephone number, the ID number, and the standard offset value for correcting the offset value when the performance test is performed under the same radio wave condition in the same environment before shipment are stored.
Reference numeral 31 is a microcomputer. This microcomputer 31 stores at least the programs of the reference offset value calculation means 20, the reception intensity correction means 21, and the reception signal selection means 22 in the ROM area (not shown), and performs processing based on the programs.

The telephone configured as described above will be described. FIG. 3 is a flowchart explaining the operation in the test mode. At the same time, in the factory, when a worker sets, for example, the level adjustment mode during the performance test (performance test mode) and the radio wave of the minimum transmission power is transmitted, the microcomputer 31 causes the A / D converter to operate. The minimum received intensity data di from the RF module output from 6 is read (S301). This minimum reception intensity is different from the normal reception intensity.

Next, the minimum reception intensity data di from the RF module 4 at this time is set as the offset value di of the RF module 4 (S303), and the level between this offset value di and the standard offset value k stored in advance. Are compared (S305). When the offset value di is larger than the standard offset value k, the offset value d
The standard offset value k is subtracted from i, and the offset difference r
i is calculated (S307). Next, this offset difference ri
Is stored (S309), it is determined whether or not a predetermined time has elapsed (S311), and if it is determined that the predetermined time has not elapsed, the control is moved to step S301, and the processes of steps S301 to S311 are executed. Also, step S3
When it is determined in 05 that the standard offset value k is larger than the offset value di of the RE module 4, the offset value di of the RF module 4 is subtracted from the standard offset value k to obtain the offset difference ri (S315), and the control is performed. Control is transferred to step S309.

When it is determined in step S311 that the predetermined time has elapsed, the offset difference ri is written and stored in the E ² PROM 30 as the reference offset D (S31).
3). As a result, the reference offset for automatically correcting the reception intensity is set.

Next, the operation will be described below when it is actually used. FIG. 4 is a flowchart explaining the operation in the normal mode. First, the microcomputer 31 reads the reception intensity data si from the RF module 4 via the A / D conversion circuit 6 (S401). Next, the absolute value difference hi of the reference offset value D stored in the E ² PROM 30 is obtained from the reception intensity data si (S40
3), the absolute value difference is calculated as the true reception intensity pi in normal time.
(S405).

Next, the stored reference reception intensity q and the stored reception intensity pi are compared to determine the level difference (S40).
7). Then, when the reference reception intensity q is larger than the reception intensity pi, a selection signal for selecting a reception signal of another antenna is output to the selection circuit 3 (S409). If it is determined in step S407 that the current reception intensity pi is greater than the reference reception intensity, the reception signal of the currently selected antenna is used as a selection signal (S411).

In the above embodiment, the E ² PROM 20
However, if the ROM area of the microcomputer has a margin, it may be stored in the ROM area. In the above embodiment, the offset value is set when the antenna 1 is used, but the antenna 2 may be used.
Further, although the reference reception intensity is set to the minimum required level in the above-mentioned embodiment, the reference reception intensity may be increased to some extent because the antenna is switched immediately by some induced noise or the like. Further, although two antennas are used in the above embodiment, a plurality of antennas may be used.

[0027]

As described above, according to the present invention, the standard offset value of the RF module is stored in advance, and during the performance test, the microcomputer stores the reception intensity of the RF module as the offset value. Since the difference between the standard offset value and the standard offset value is set as the reference offset, the optimum reference offset value can be set automatically, and the time for adjusting the offset value of the RF module during the performance test can be shortened. The effect is obtained.

Further, by the microcomputer, R
In addition to automatically adjusting the offset value of the F module, the difference between the reference offset value and the reception intensity from the RF module is normally regarded as the true reception intensity, and based on the level difference between the reception intensity and the reference reception intensity, the antenna By selecting the reception signal, the effect of simplifying the configuration of the device is obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of a cordless telephone of the present invention.

FIG. 2 is a schematic configuration diagram of a specific example of a cordless telephone of the present invention.

FIG. 3 is a flowchart illustrating an operation in a test mode.

FIG. 4 is a flowchart illustrating an operation in a normal mode.

FIG. 5 is a configuration diagram for a performance test of a conventional cordless telephone.

[Explanation of symbols]

1 Antenna 2 Antenna 3 Selection Circuit 4 RF Module 5 Level Adjustment Circuit 6 A / D Converter 11 Microphone 12 Speaker 20 Reference Offset Value Calculation Means 21 Reception Strength Correction Means 22 Reception Signal Selection Means 30 E ² PROM 31 Microcomputer

Claims (2)

[Claims] 1. A selection circuit for selecting a high frequency reception signal received by one of antennas arranged at mutually different positions and outputting the selected high frequency reception signal; and inputting the high frequency reception signal for receiving the high frequency reception signal. At least an RF module that calculates and outputs the reception strength of the signal, and when it is notified that the performance test is performed, the reception strength from the RF module is set as an offset value of the RF module, and the offset value is stored in advance. A standard offset value calculating means for storing a difference from a standard offset value as a standard offset value; and when the performance test is canceled, the standard reception value is set to the standard reception value each time the reception strength is output from the RF module. A reception strength correction means for correcting the reception strength based on the offset value; Compared with a reference reception intensity stored, cordless telephone and having always a reception signal selection means for the antenna to obtain a high-frequency reception signal such that above the reference reception strength is selected to the selection circuit. 2. The cordless telephone according to claim 1, wherein the reference offset value calculation means, the reception intensity correction means and the reception reception signal selection means are implemented by a microcomputer.