JPH09322256A - Analog cordless telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the analog cordless telephone set in which misdiscrimination of reception of a header is not caused and no adverse effect is caused on a speech even when signals with a prescribed frequency are continuously received. SOLUTION: In the case of discriminating a run length from a pulse width of a reception signal by a control section 106, for example, 1-bit is represented by a signal of 1ms in a header, then 1.5ms is set as a threshold level to discriminate a signal representing data by one bit or a signal representing data by two bits to a threshold level storage section 1064 in the usual state and after the signal representing data by two bit is received, till the header is detected, the threshold level is revised into 1.35ms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog cordless telephone.

[0002]

2. Description of the Related Art In analog cordless telephones,
When receiving a call from the outside, or when a call request is made from the child device to the parent device,
When the master unit and the slave unit have to exchange necessary information with each other, a control signal of a predetermined format is wirelessly exchanged. For example, the master unit sends a control signal to the slave unit to notify it when an incoming call is received from the outside, and when a call request is made from the slave unit, the control signal from the slave unit is received and externally transmitted. Connection with
Processing such as transmission of a control signal notifying the result is performed. In addition, in the slave unit, in addition to transmitting a control signal for notifying the call request to the master unit when the call request from the slave unit,
When an incoming call is received from the outside, the control signal transmitted from the master unit is received, and a process of transmitting a control signal indicating that the call is possible to the master unit is performed.

FIG. 3 is a diagram showing an example of a format of a control signal. The control signals shown in the figure are header,
Includes security code, channel code, control code, etc. A group of these data will be hereinafter referred to as "one frame". However, in the figure, the "data pre-processing" and "data post-processing" portions are not included in one frame. Here, the header is a code indicating that it is a control signal, and 16 bits are allocated. In this example, a binary 16-bit code representing "9336" is used, but this code is the RCR in Japan.
STD-13 of (Radio System Development Center of Japan)
It is recommended to be used according to the standard.

The security code is a code determined in advance between a pair of a master unit and a slave unit, and is used to identify whether it is a control signal from the master unit or the slave unit corresponding to its own unit. Used. The channel code is a code that represents the frequency of a carrier wave used for communication between the master unit and the slave unit, and the control code is information that is exchanged by a control signal such as an incoming call or a call request from the outside. Is a code that represents the type of.

When the reception of the header is detected in the slave unit, the control unit of the slave unit mutes (hereinafter referred to as "RXMUTE") in order to prevent leakage of data noise from the speaker. Specifically, in the process of demodulating and amplifying the received signal, the speaker is controlled so as not to be amplified so that no sound is output from the speaker. This is because the voice signal and the control signal during a call use the same channel, and if the control signal is demodulated and amplified as it is and output from the speaker, it becomes a large noise. After that, the security code is sequentially checked, and if all are present, RXMUTE for one frame is continuously applied. If the security code is incorrect, RXMUTE is released at that point. Similarly, mute is also used in the parent device. The mute in this case is to prevent the data noise from leaking to the voice transmitted to the other party via the line.

The operation of muting will be further described with a slave unit as a representative. The control unit of the slave unit must first determine whether or not the header has been received. However, since the control signal is sent as pulse data as shown in FIG. 3, the pulse width is measured to determine what the received signal is. It must be determined if the signal represents data. Here, since 16 bits are represented by a signal of 16 milliseconds in the header, the control unit of the child device determines that the signal has the same logical value depending on how many milliseconds the signal having the same logical value is transmitted. It is necessary to determine how many bits are represented.

A software timer is used to measure the pulse width. Specifically, by generating an interrupt when the received signal changes from the low level to the high level and when the received signal changes from the high level to the low level,
The software timer is started, and when the next interrupt occurs, the counter value incremented by the software timer is taken out and the pulse width is measured. By comparing the measured pulse width with a predetermined threshold value, it is determined how many bits of data the pulse width of the received signal represents.

In the conventional analog cordless telephone, when judging the data at this time, considering variations due to hardware or variations in pulse width due to flight distance, etc., 1
The threshold value for identifying whether the data is the bit data or the 2-bit data is set to 1.5 milliseconds. That is, if the pulse width is 0.5 to 1.5 milliseconds, it is recognized as 1 millisecond, that is, 1 bit of data, and if the pulse width is 1.5 to 2.5 milliseconds, 2 milliseconds, That is, it was recognized as data of 2 bits. FIG. 4 shows the timing when RXMUTE is applied when a regular header is received.

[0009]

By the way, the threshold value of 1.5 milliseconds for discriminating between 1-bit data and 2-bit data is approximately equal to the frequency. It becomes 333 Hz. In an analog cordless telephone, the receivable frequency band is often set to about 300 Hz to 3.4 KHz in accordance with the voice band, but in the conventional analog cordless telephone, the frequency is about 333 Hz (the above-mentioned voice A micro control unit (hereinafter referred to as “MC”) that measures the reception time when a signal within the band is continuously received.
There is a problem in that the header may be erroneously determined to have been received due to the occurrence of a measurement error (referred to as “U”). More specifically, as shown in FIG.
Even if it is necessary to generate an interrupt at time points B and B to measure the pulse width, at time A, if an interrupt with a higher priority than the processing related to the activation of the software timer occurs, the software timer is activated. The processing such as is delayed, and the measurement start timing is delayed until the time point A ′. On the other hand, since the increment processing of the counter of the software timer is usually given a priority close to the highest priority, the deviation of the activation timing of the software timer directly leads to a pulse width measurement error. That is, when the signal between the ABs is slightly longer than 1.5 milliseconds, the pulse width between the ABs, which should originally be determined to be data of 2 bits, is shorter than the actual due to the delay in the start of measurement. Since it is measured, it is erroneously determined to represent one bit of data.

As a result, as shown in FIG.
When the Hz signal is continuously received, the received signal represents "9336", for example, when the portions indicated by A and B in the figure are erroneously determined to be 1-bit signals. Therefore, there is a case where the header is received and a misjudgment is made. When it is determined that the header has been received, the slave unit control unit performs RXMUTE. Therefore, if the event occurs during a call, there is a problem that the call may be adversely affected.

In view of the above problems, the present invention provides an analog cordless telephone which does not adversely affect a call due to an erroneous determination of the pulse width even when signals of the above frequencies are continuously received. The purpose is to

[0012]

In order to solve the above problems, an analog cordless telephone according to the present invention wirelessly transmits a digital control signal of a predetermined format between a parent and child prior to or accompanying an analog call. In an analog cordless telephone that operates in the same manner, receiving means for receiving a digital control signal, measuring means for measuring the duration of the same logical value in the digital control signal, duration measured by the measuring means, and a plurality of duration-related Based on a predetermined threshold value, the determination means for determining the bit length of the same logical value, and the determination means, if the digital control signal is determined to have a predetermined bit length, then in a predetermined period Over the range, it is determined whether the predetermined bit length is the predetermined bit length or the bit length is one less than the bit length. And a threshold changing means for reducing the threshold.

Further, in the above analog cordless telephone, the predetermined bit length can be set to 2.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a slave unit of the analog cordless telephone according to the present embodiment. The analog cordless telephone shown in the figure includes an antenna 101, a duplexer 102, and a receiver 10.
3, SP amplifier 104, speaker 105, control unit 10
6, an operation unit 107, a microphone 108, a switch 109, a transmission unit 110, a secondary battery 111, a regulator 112, and switches 113 and 114.

The control unit 106 also includes a logical value determination unit 10
61, bit length determination unit 1062, software timer 1
063, threshold value holding unit 1064, code determination unit 106
5, including the RXMUTE control unit 1066. Antenna 10
1 transmits and receives a radio signal. Duplexer 1
02 is used to share one antenna for transmission and reception.

The receiving section 103 includes an RF amplifier, a local oscillator circuit, a mixer, an IF amplifier and a detector, and the antenna 1
01 extracts the received data from the wireless signal received by 01, and S
It is sent to the P amplifier 104 and the control unit 106. Control unit 106
Analyzes received control signals, controls RXMUTE, etc.
Control the entire slave unit. Specifically, a microcomputer such as "LC66 series" manufactured by Sanyo Electric Co., Ltd. can be used.

The logical value determining unit 1061 determines whether the received signal received from the receiving unit 103 is a signal representing a logical value "0" (low level) or a signal representing a logical value "1" (high level). To judge. The bit length determination unit 1062
In response to the determination by the logical value determination unit 1061, the receiving unit 10
It is determined how many bits of the determined logical value the received signal received from 3 represents. Specifically, as described above, when the logical value represented by the received signal changes from the low level to the high level, and when the logical value changes from the high level to the low level, the software timer 1063 is started by hardware-like interrupt processing. Then, the pulse width is measured by interrupt processing due to the next change in the logical value, and the software timer 1063 is restarted.

The bit length determination unit 1062 compares the measured pulse width with the threshold value held in the threshold value holding unit 1064, so that the received signal represents the number of bits of the logical value. Is determined. The judgment result is
The codes are sequentially sent to the code determination unit 1065 and stored in the buffer. Further, the bit length determination unit 1062 switches the threshold value held in the threshold value holding unit 1064 as necessary. The switching of the threshold value will be described in detail later.

The code determination unit 1065 sequentially stores the determination results sent from the threshold value storage unit 1064 in the buffer and determines whether the header is a predetermined header. If the result of determination is that the header has been received, RX
It instructs RXMUTE to the MUTE control unit 1066. R
The XMUTE control unit 1066 controls RXMUTE according to the instruction of the code determination unit 1065. In particular,
When the code determination unit 1065 recognizes the reception of the header, the SP amplifier 104 is controlled to apply RXMUTE, and the output of the sound from the speaker 105 is stopped. If the security codes do not match after that, RXMUTE is canceled at that point,
If the security codes also match, RXMUTE is continued for one frame.

The transmission section 110 includes a local oscillation circuit and an RF amplifier, modulates and amplifies the control signal generated by the control section 106 and the voice signal input from the microphone 108, and outputs the modulated signal from the antenna 101. Next, processing contents of the control unit 106 in the analog cordless telephone according to the present embodiment will be described. FIG. 2 is a flow chart showing the detailed processing contents of the control unit 106.

The controller 106 first measures the pulse width of the received signal sent from the receiver 103 (S20).
1). Specifically, the logical value determination unit 1061 determines whether the received signal is at a low level or a high level, and based on the determination, the bit length determination unit 1062
The on-edge (when the signal changes from the low level to the high level) and the off-edge (when the signal changes from the high level to the low level) of the received signal are detected. Further, as described above, when the on-edge or off-edge is detected, the interrupt process is generated and the software timer 1
The pulse width measured in 063 is measured, the contents of the software timer 1063 are cleared, and the process is restarted.

Next, the bit length judgment unit 1062 refers to the threshold value holding unit 1064, and the threshold value for judging 1 ms data and 2 ms data becomes 1.35 ms. It is determined whether or not there is (S202). When the threshold value is not 1.35 milliseconds (S202: No), it is determined whether the pulse width is 0.5 to 1.5 milliseconds (S203) and the pulse width is 0.5 to 0.5. If it is 1.5 milliseconds, it is recognized as a signal of 1 millisecond (S204), the data is stored in the buffer provided in the code determination unit 1065 (S205), and the processing of the control unit 106 ends. To do. In this way, the determination result is sequentially stored in the buffer, and the header recognition is performed by sequentially determining the storage result every 8 bits.

On the other hand, if the pulse width is not 0.5 to 1.5 milliseconds in step S203, it is next determined whether or not the pulse width is 1.5 to 2.5 milliseconds. If the pulse width is 1.5 to 2.5 milliseconds (S206), it is recognized as a signal of 2 milliseconds (S207), and the threshold for pulse width measurement is changed to 1.35 milliseconds. (S2
08), the data is stored in the buffer (S205), and the processing of the control unit 106 ends.

If the pulse width is not 1.5 to 2.5 milliseconds in step S206, it is determined that the received signal is noise (S209), and the processing of the control unit 106 is ended. When it is determined in step S202 that the threshold value of the pulse width is 1.35 milliseconds,
This means that it has been determined that a signal of 2 milliseconds has already been received. In this case, the bit length determination unit 1062
Determines whether the pulse width is 0.5 to 1.35 milliseconds (S210). When it is determined that the pulse width is 0.5 to 1.35 milliseconds, the received signal is recognized as a signal of 1 millisecond (S211), the data is stored in the buffer (S212), and " It is determined whether or not a signal representing "9336" has been received (S213). More specifically, if the first 8-bit data stored in the buffer is data representing "93", and if the next 8 bits are a signal representing "36", a signal representing "9336". Will be determined to have been received.

When the input of the signal "9336" is recognized (S213: Yes), it is recognized that the header has been received, and the RXMUUTE control unit 1066 informs the RXMU.
An instruction is sent to apply TE (S214). further,
The threshold value of the pulse width is changed from 1.35 milliseconds to 1.5 milliseconds (S215), and the processing of the control unit 106 ends.

In step S210, the pulse width is 0.
When it is determined that the pulse width is not 5 to 1.35 milliseconds, it is determined whether the pulse width is 1.35 to 2.5 milliseconds (S216), and the pulse width is 1.35 to 2.5. If it is millisecond, it is recognized that a signal of 2 milliseconds has been received (S21
7) and proceeds to step S212. If it is determined in step S216 that the pulse width is not 1.35 to 2.5 milliseconds, it is determined that the received signal is noise (S218), and the pulse width threshold value is 1.35 milliseconds. From 1.5 milliseconds (S215), the control unit 106
Is completed.

As described above, when the reception of the signal of 2 milliseconds is detected, the threshold value for determining whether it is the signal of 1 millisecond or the signal of 2 milliseconds is 1.5 milliseconds. From 1.
By changing to 35 milliseconds, even if the interrupt for instructing the software timer to start measuring the bit width is delayed by an interrupt with a higher priority, 2
A signal representing one bit of data is no longer erroneously determined to be a signal representing one bit of data, and when a header is "9336", RXMUTE is generated due to an erroneous detection of the header. This has the effect of preventing adverse effects.

In this embodiment, the header is "9".
336 "has been described in detail, but even if a problem occurs using another header, the cause is a delay in the start of measurement by the software timer due to the occurrence of higher priority processing such as an interrupt. As long as it is, it can be easily applied. In the present embodiment,
Although the application example of the analog cordless telephone to the child device has been described in detail, it may be applied to the parent device. In this case, the difference is that muting is performed on the transmission of the transmission voice to the other party via the line, but the header detection is exactly the same, and the control unit of the master unit is the control unit of the control unit 106 of FIG. May be provided.

[0029]

As is apparent from the above description, the analog cordless telephone according to the present invention is an analog cordless telephone that wirelessly exchanges a digital control signal of a predetermined format between a parent and child prior to or accompanying an analog call. In a telephone, receiving means for receiving a digital control signal, measuring means for measuring the duration of the same logical value in the digital control signal, duration measured by the measuring means, and a plurality of predetermined threshold values for duration. And a determination unit that determines the bit length of the same logical value based on the above, and if the determination unit determines that the digital control signal has a predetermined bit length, then the plurality of the plurality of units are connected for a predetermined period. Of the predetermined threshold values, the threshold value for determining whether the predetermined bit length is 1 or less than 1 is smaller than the predetermined bit length. And a Kusuru threshold change means.

When the determination means determines that the digital control signal has a predetermined bit length, the threshold value changing means then determines whether the digital control signal has a predetermined bit length among the plurality of predetermined threshold values. , A bit for the software timer for measuring the pulse width of the reception signal by reducing the threshold value for determining whether the bit length is the predetermined bit length or the bit length which is one less than the bit length. Even if the interrupt for instructing the start of width measurement is delayed due to the occurrence of an interrupt with a higher priority, it is possible to prevent a 2-bit length signal from being erroneously determined to be 1-bit length. As a result, even if the same continuous voice frequency in a call is similar to the control signal, it is not erroneously determined that the header of the control signal is received.
It is possible to prevent the UTE from adversely affecting the call.
Specifically, when applied to a child device, it is possible to prevent the adverse effect that the received voice is interrupted, and when applied to the parent device, it is possible to prevent the adverse effect that the transmitted voice from the line to the other party is interrupted. . .

In the analog cordless telephone set, the predetermined bit length can be set to 2. By setting the predetermined bit length to 2, it is possible to prevent an erroneous determination of data when "9336" is used as the header.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an analog cordless telephone according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the processing contents of the control unit of the analog cordless telephone according to the embodiment of the present invention.

FIG. 3 is a diagram showing an example of a format of a control signal.

FIG. 4 is a diagram for explaining data determination when a regular header is received.

FIG. 5 is a diagram for explaining a pulse width measurement error by the MCU.

FIG. 6 is a diagram for explaining an erroneous determination of data when a signal of a frequency 333 Hz is continuously received in a conventional analog cordless telephone.

[Explanation of symbols]

 101 antenna 102 duplexer 103 receiving unit 104 SP amplifier 105 speaker 106 control unit 107 operating unit 108 microphone 109 switch 110 transmitting unit 111 secondary battery 112 regulator 113 switch 114 switch 1061 logical value determining unit 1062 bit length determining unit 1063 software timer 1064 Threshold value holding unit 1065 Code determination unit 1066 RXMUTE control unit

Claims (2)

[Claims] 1. An analog cordless telephone for wirelessly exchanging a digital control signal of a predetermined format between a parent and child prior to or accompanying an analog call, and the receiving means for receiving the digital control signal and the same digital control signal. Measuring means for measuring the duration of the logical value, the duration measured by the measuring means, based on a plurality of predetermined threshold values for the duration, the determination means for determining the bit length of the same logical value, In the case where the determination means determines that the same logical value has a predetermined bit length, whether the predetermined bit length is the predetermined bit length among the plurality of predetermined threshold values over a predetermined period thereafter. An analog cordless telephone, comprising: a threshold changing means for reducing a threshold for determining whether the bit length is one less than the bit length. 2. The analog cordless telephone according to claim 1, wherein the predetermined bit length is 2.