JP2007067786A - Received electric field intensity signal measuring circuit of radio communication set - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine whether there is a received signal based upon an RSSI signal, and to enter a low-power-consumption mode when it is determined that there is no received signal. <P>SOLUTION: A received electric field intensity signal measuring circuit comprises: an A/D converter which extracts a received electric field intensity signal from a received signal, converts the received electric field intensity signal from an analog value to a digital value, and outputs the digital data value; and a control circuit which controls the A/D converter to read in the digital data value output from the A/D converter. The A/D converter is provided with a timing generation section which outputs the digital data value and an interruption request signal during operation to control sampling and the operation/stop of the A/D converter, and the control circuit sets measurement timing generated by the timing generation section, cancels the low-power-consumption mode in response to the interruption request signal from the A/D converter, and reads in the digital data value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a received signal strength (RSSI) measuring circuit of a wireless communication device.

A conventional received signal strength (RSSI) measuring circuit of a wireless communication device outputs a detection current by comparing a plurality of limiter amplifiers that amplify an input signal and output signals of the plurality of limiter amplifiers with a reference voltage. A reference current source circuit that generates a reference current in a signal strength detection circuit that detects a signal strength by a plurality of detection circuits that perform detection, and an output circuit that converts the detection current of the plurality of detection circuits into a voltage and smoothes the voltage, And a bias power supply circuit for subtracting the detection current obtained by the detection circuit from the reference current of the reference current source circuit, and receiving electric field for detecting the signal intensity by the current output of the difference obtained by subtracting the detection current from the reference current An intensity (RSSI: Received Signal Indicator) measurement circuit is known. (For example, refer to Patent Document 1).
A method is also known in which a received signal is taken out from an intermediate frequency circuit, diode-detected, a detection output is integrated, and a received electric field strength (RSSI: Received Signal Indicator) signal is taken out.
A received signal indicator (RSSI) signal (hereinafter also referred to as RSSI signal) extracted by these methods is converted into a digital value by an A / D converter, and is checked at a constant cycle, for example, 100 ms. If it is read by a computer and the intensity is higher than a predetermined level, it can be known whether a desired signal is received.
Japanese Utility Model Publication No. 7-42235

According to the received signal strength (RSSI) measuring circuit configured as described above, the received field strength can be known at a constant period, and it can be always known whether a desired received wave is received. However, received field strength (RSSI: Received
No consideration was given to the power consumption for the Signal Indicator) measurement circuit.

  On the other hand, as shown in FIG. 3, the conventional receiver of the wireless communication device supplies the signal received by the antenna 11 to the receiving unit 12, and the receiving unit 12 selects the signal from the received signals. The received signal is converted to an intermediate frequency and detected, and an RSSI signal is output from the receiving unit 12. The RSSI signal is supplied to the A / D converter 13, and the A / D converter 13 converts an analog value into a digital value and outputs the digital value to the control circuit 14 including a microcomputer.

  At this time, the control circuit 14 manages the measurement timing of the RSSI signal. When the measurement timing managed by the control circuit 14 is reached, the control circuit 14 instructs the A / D converter 13 to start A / D conversion. After the A / D conversion is completed, the control circuit 14 reads the digital value of the RSSI signal from the A / D converter 13.

  If the digital value of the RSSI signal read under the control of the control circuit 14 composed of a microcomputer for receiving field strength measurement control is equal to or greater than a predetermined value, it is considered that a received signal exists.

In the received signal strength (RSSI) measuring circuit of the conventional wireless communication apparatus shown in FIG. 3, the A / D converter is controlled at a constant cycle by a control circuit composed of a microcomputer regardless of the presence or absence of a received signal. In order to read the RSSI signal converted into the digital signal, the control circuit composed of the microcomputer needs to operate regardless of the presence or absence of the received signal, and further receives the received electric field strength (RSSI: Received).
(Signal Indicator) Since the measurement timing is managed, there is a problem that the low power consumption mode cannot be set and the power consumption is large.
Similarly, the A / D converter cannot be stopped and power consumption cannot be reduced.

The present invention determines the presence or absence of a received signal based on the received field strength (RSSI: Received Signal Indicator), and determines that the received signal does not exist. Received
Signal Indicator) An object is to provide a measurement circuit.

The reception field strength signal measurement circuit for a wireless communication device according to claim 1 of the present invention extracts a reception field strength signal from a received reception signal, converts the reception field strength signal from an analog value to a digital value, and outputs the digital data value as a digital data value In the received electric field strength signal measuring circuit of the wireless communication device comprising the A / D converter and the control circuit for controlling the A / D converter and reading the digital data value output from the A / D converter,
The A / D converter outputs a digital data value and an interrupt request signal during operation, and includes a timing generation unit that controls sampling and operation / stop of the A / D converter, and the control circuit includes the timing generation unit The measurement timing generated in step (1) is set, the low power consumption mode is canceled by the interrupt request signal from the A / D converter, and the digital data value is read.

A reception field strength signal measurement circuit for a wireless communication device according to claim 2 of the present invention extracts a reception field strength signal from a received reception signal, converts the reception field strength signal from an analog value to a digital value, and outputs it as a digital data value In the received electric field strength signal measuring circuit of the wireless communication device comprising the A / D converter and the control circuit for controlling the A / D converter and reading the digital data value output from the A / D converter,
The A / D converter outputs a digital data value during operation, and a threshold determination unit that determines whether or not the digital data value of the A / D converter is equal to or greater than a predetermined threshold, and the threshold determination unit An interrupt request signal is output based on the A / D converter, and a timing generation unit that controls sampling / operation / stop of the A / D converter is provided. The control circuit sets a measurement timing generated by the timing generation unit, and the threshold value The low power consumption mode is canceled by an interrupt request signal from the determination unit, and a digital data value is read.

According to a third aspect of the present invention, there is provided a reception field strength signal measurement circuit for a wireless communication device that extracts a reception field strength signal from a received reception signal, converts the reception field strength signal from an analog value to a digital value, and outputs the digital data. In a received electric field strength signal measuring circuit of a wireless communication device comprising an A / D converter and a control circuit that controls the A / D converter and reads a digital data value output from the A / D converter.
The A / D converter outputs a digital data value during operation,
An average value calculation unit for calculating an average digital data value of the digital data values of the A / D converter;
A threshold value determination unit for determining whether an average digital data value of the average value calculation unit is equal to or greater than a predetermined threshold value; and the threshold value determination unit outputs an interrupt request signal based on the threshold value determination, and the A / D converter A timing generator that controls the sampling and operation / stop of
The control circuit sets a measurement timing generated by the timing generation unit, cancels the low power consumption mode by an interrupt request signal from the threshold determination unit, and reads digital data.

According to the received electric field strength signal measuring circuit of the wireless communication device of the first aspect of the present invention, the received received signal is detected, the received electric field strength signal is extracted, and the received electric field strength signal is converted from an analog value to a digital value. In a reception electric field strength signal measurement circuit of a wireless communication device comprising an A / D converter that outputs data values and a control circuit that controls the A / D converter and reads digital data values output from the A / D converter.
The A / D converter outputs an interrupt request signal during operation, and the control circuit is shifted from the low power consumption mode to the normal power consumption mode by the interrupt request signal from the A / D converter, and the received electric field strength signal Since measurement is started, power consumption can be reduced.

According to the received electric field strength signal measuring circuit of the wireless communication device of the second aspect of the present invention, the received received signal is detected, the received electric field strength signal is extracted, and the received electric field strength signal is converted from an analog value to a digital value. In a received electric field strength signal measuring circuit comprising an A / D converter that outputs data values and a control circuit that controls the A / D converter and reads the digital data values output from the A / D converter.
The A / D converter outputs a digital data value during operation, and determines whether or not the digital data value of the A / D converter is equal to or greater than a predetermined threshold. The threshold determination unit is based on the threshold determination. Outputs an interrupt request signal. In response to the interrupt request signal, the control circuit shifts from the low power consumption mode to the normal power consumption mode. Based on the threshold determination, the control circuit reliably determines the presence / absence of a received signal and shifts from the low power consumption state to the normal power consumption state, thereby reducing power consumption.

According to the received electric field strength signal measuring circuit of the wireless communication device of the third aspect of the present invention, the received received signal is detected, the received electric field strength signal is extracted, and the received electric field strength signal is converted from an analog value to a digital value. In a reception electric field strength signal measurement circuit of a wireless communication device comprising an A / D converter that outputs data values and a control circuit that controls the A / D converter and reads digital data values output from the A / D converter.
The A / D converter outputs a digital data value during operation, and calculates an average digital data value of the digital data values of the A / D converter, and an average digital data value of the average value calculation unit is a predetermined threshold value Since the threshold value determination unit that determines whether or not the threshold value and the threshold value determination unit output an interrupt request signal based on the threshold value determination, the reception field strength signal is input to the average value calculation unit. The average value of is calculated. An average received electric field strength signal obtained as a result of the average calculation is input to the threshold value determination unit, and the threshold value determination unit determines whether the average received electric field strength signal is equal to or greater than a predetermined threshold value. Only when it is determined that the received electric field strength signal is greater than or equal to the threshold value, an interrupt request signal is sent from the threshold value determination unit. In this case, since the average value of the received electric field strength signal is calculated and the average received electric field strength signal is compared with the threshold value, even if the received electric field strength signal varies, it is averaged and the influence on the determination in the threshold value judgment is reduced. Is done.

  In response to the interrupt request signal, the control circuit shifts from the low power consumption mode to the normal power consumption mode and starts measuring the received electric field strength signal. The control circuit shifts from the normal power consumption mode to the low power consumption mode if the received electric field strength signal is equal to or less than the threshold value. As described above, the control circuit shifts from the normal power consumption mode to the low power consumption mode if the received electric field strength signal is equal to or less than the threshold value, and thus the power consumption of the wireless communication device can be reduced.

  Hereinafter, a received electric field strength signal measuring circuit of a wireless communication device according to the present invention will be described with reference to embodiments.

  FIG. 1 is a block diagram showing a configuration of a receiver having a received electric field strength signal measuring circuit of a wireless communication device according to an embodiment of the present invention.

  A receiver 30 having a reception field strength signal measurement circuit for a wireless communication apparatus according to an embodiment of the present invention is configured as shown in FIG. In the receiver 30, the signal received by the antenna 11 is supplied to the receiving unit 12, and the receiving unit 12 selects a desired signal from the received signals, converts the selected received signal to an intermediate frequency, and then performs diode detection. Then, the detection output is integrated and an RSSI signal corresponding to the received electric field strength is output from the receiving unit 12 as an RSSI signal.

  The RSSI signal output from the receiving unit 12 is supplied to the A / D converter 15. The A / D converter 15 starts an operation of converting the RSSI signal supplied from the receiving unit 12 from an analog signal to a digital signal. The A / D converter 15 which has completed the operation of converting the RSSI signal from the analog signal to the digital signal outputs a digital data value and supplies an interrupt request signal to the control circuit 16 formed of a microcomputer. The control circuit 16 switches from the low power consumption mode to the normal power consumption mode in accordance with the interrupt request signal. The control circuit 16 can switch to the normal power consumption mode, read the digital value of the RSSI signal, and know the presence or absence of the desired received signal.

  Further, the receiver 30 includes a timing generation unit 17 in which measurement timing is set by a control circuit 16 formed of a microcomputer for controlling the received electric field strength signal measurement circuit. When the set timing is reached, the timing generation unit 17 outputs a sampling pulse having a predetermined cycle, which is a measurement start signal, to the A / D converter 16, and the A / D converter 16 that has received the sampling pulse enters an operating state. An operation for sampling the RSSI signal input to the / D converter 16 based on the sampling pulse and converting it to a digital signal is started. In addition, when the conversion of the RSSI signal from the analog signal to the digital signal is completed, the A / D converter 16 stores the measurement result in the register and outputs an interrupt request signal to the control circuit 16. The control circuit 16 switches from the low power consumption mode to the normal power consumption mode in accordance with the interrupt request signal. The register of the A / D converter 16 is read, and the A / D converter 16 ends the operation under the control of the timing generation unit 17. The control circuit 16 is again in the low power consumption mode.

In this way, the operation of the A / D converter 15 is controlled by the timing generation unit 17, and the control circuit 16 switches from the low power consumption mode to the normal power consumption mode according to the interrupt request signal from the A / D converter 16. Controlled by the timing generator 17, the operation of the A / D converter 15 is also stopped, and the measurement timing setting of the timing generator 17 is set by the control circuit 16, so that the power consumption of the wireless communication device is suppressed.

Next, a received electric field strength signal measuring circuit of a wireless communication device according to the present invention will be described with another embodiment.

  FIG. 2 is a block diagram showing a configuration of a receiver having a received electric field strength signal measuring circuit of a wireless communication device according to another embodiment of the present invention.

  A receiver 40 having a reception field strength signal measurement circuit for a wireless communication apparatus according to another embodiment of the present invention is configured as shown in FIG. In the receiver 40, the signal received by the antenna 11 is supplied to the receiving unit 12, and the receiving unit 12 selects a signal from the received signals, converts the selected received signal into an intermediate frequency, and then performs diode detection. Then, the detection output is integrated to output an RSSI signal corresponding to the received electric field intensity from the receiving unit 12 as an RSSI signal.

  The RSSI signal output from the receiving unit 12 is supplied to the A / D converter 20. The A / D converter 20 starts an operation of converting the RSSI signal supplied from the receiving unit 12 from an analog signal to a digital signal. After completing the operation of converting the RSSI signal from the analog signal to the digital signal, the A / D converter 20 supplies the output of the digital data value to the control circuit 21 including the microcomputer, the threshold value determination unit 23, and the average value calculation unit 24.

The receiver 40 includes a timing generation unit 17 in which measurement timing is set by a control circuit 21 including a microcomputer for controlling a received electric field strength signal measurement circuit. When the set timing is reached, the timing generation unit 17 outputs a sampling pulse having a predetermined period, which is a measurement start signal, to the A / D converter 20, and the A / D converter 20 that has received the sampling pulse is in an operating state. The operation for sampling the RSSI signal input to the / D converter 20 based on the sampling pulse and converting it to a digital signal is started. Further, the A / D converter 20 stores the measurement result in the register when the conversion of the RSSI signal from the analog signal to the digital signal is completed.

Further, the receiving unit 40 includes a threshold value determining unit 23 and an average value calculating unit 24 controlled by a control circuit 21 formed of a microcomputer for controlling a received electric field strength signal measuring circuit. The threshold value determination unit 23 is supplied with the digital value of the RSSI signal from the A / D converter 20. In the threshold determination unit 23, a predetermined RSSI signal threshold is set by the control circuit 21. The threshold determination unit 23 compares the digital value of the measurement result RSSI signal from the A / D converter 20 with a preset threshold. The threshold determination unit 23 determines whether the digital value of the RSSI signal that is the measurement result from the A / D converter 20 exceeds the threshold. If the threshold does not exceed the threshold, the threshold determination field 23 sends the control circuit 21 to the control circuit 21. On the other hand, the interrupt request signal is not supplied, and the supply of the digital value of the RSSI signal from the A / D converter 20 is awaited. The threshold determination unit 23 determines whether the digital value of the RSSI signal, which is the measurement result from the A / D converter 20, exceeds the threshold. If the threshold exceeds the threshold, the threshold determination unit 23 sends an interrupt request signal to the control circuit 21. Supply.
The control circuit 21 switches from the low power consumption mode to the normal power consumption mode in accordance with the interrupt request signal. The control circuit 21 reads the register of the A / D converter 20, and the A / D converter 20 ends the operation under the control of the timing generation unit 17. The control circuit 21 enters the low power consumption mode again.

  The average value calculation unit 24 performs an operation of taking and averaging the digital value of the RSSI signal supplied from the A / D converter 20 a predetermined number of times. The control circuit 21 composed of a microcomputer sets the number of operations of the average value calculation unit 24. The threshold determination unit 23 inputs the digital value of the averaged RSSI signal, determines whether the digital value of the averaged RSSI signal is equal to or lower than a predetermined threshold, and is equal to or higher than the threshold. The interrupt request signal is sent to the control circuit 21 only when it is determined.

  When the control circuit 21 receives the interrupt request signal output from the threshold determination unit 23, the control circuit 21 considers that there is a possibility that a received signal exists, and shifts from the low power consumption mode to the normal power consumption mode. Measurement of the RSSI signal output from the converter 20 is started. The control circuit 21 reads the register of the A / D converter 20, and the A / D converter 20 ends the operation under the control of the timing generation unit 17. The control circuit 21 enters the low power consumption mode again.

In this way, the control circuit 23 can remain in the low power consumption mode until the RSSI signal exceeds the threshold value, so that the power consumption can be further reduced.
In addition, since the average value calculation unit 24 averages the RSSI signal, even if the RSSI signal suddenly changes for some reason, the influence can be reduced.

It is a block diagram which shows the structure of the receiver which has a received electric field strength signal measuring circuit of the radio | wireless communication apparatus concerning one Embodiment of this invention. It is a block diagram which shows the structure of the receiver which has a received electric field strength signal measurement circuit of the radio | wireless communication apparatus concerning the other embodiment of this invention. It is a block diagram which shows the structure of the receiver which has the conventional received electric field strength signal measuring circuit of a radio | wireless communication apparatus.

Explanation of symbols

12 Receiver
13, 15 and 20 A / D converters 14, 16 and 21 Control circuit 17 Timing generation unit 23 Threshold determination unit 24 Average value calculation unit 30 and 40 Receiver

Claims (5)

An A / D converter that extracts a received electric field strength signal from a received signal, converts the received electric field strength signal from an analog value to a digital value, and outputs it as a digital data value, and controls the A / D converter. From the A / D converter In the received electric field strength signal measuring circuit of the wireless communication device comprising the control circuit that reads the output digital data value,
The A / D converter outputs a digital data value and an interrupt request signal during operation, and includes a timing generation unit that controls sampling and operation / stop of the A / D converter, and the control circuit includes the timing generation unit A measurement circuit for receiving electric field strength signal of a wireless communication device, which sets a measurement timing generated in step A, cancels a low power consumption mode by an interrupt request signal from an A / D converter, and reads a digital data value. An A / D converter that extracts a received electric field strength signal from a received signal, converts the received electric field strength signal from an analog value to a digital value, and outputs it as a digital data value, and controls the A / D converter. From the A / D converter In the received electric field strength signal measuring circuit of the wireless communication device comprising the control circuit that reads the output digital data value,
The A / D converter outputs a digital data value during operation, and a threshold determination unit that determines whether or not the digital data value of the A / D converter is equal to or greater than a predetermined threshold, and the threshold determination unit An interrupt request signal is output based on the A / D converter, and a timing generation unit that controls sampling / operation / stop of the A / D converter is provided. The control circuit sets a measurement timing generated by the timing generation unit, and the threshold value A reception field strength signal measurement circuit for a radio communication device, wherein a low power consumption mode is canceled by an interrupt request signal from a determination unit and a digital data value is read. An A / D converter that extracts a received electric field strength signal from a received signal, converts the received electric field strength signal from an analog value to a digital value, and outputs it as a digital data value, and controls the A / D converter. From the A / D converter In the received electric field strength signal measuring circuit of the wireless communication device comprising the control circuit that reads the output digital data value,
The A / D converter outputs a digital data value during operation,
An average value calculation unit for calculating an average digital data value of the digital data values of the A / D converter;
A threshold value determination unit for determining whether an average digital data value of the average value calculation unit is equal to or greater than a predetermined threshold value; and the threshold value determination unit outputs an interrupt request signal based on the threshold value determination, and the A / D converter A timing generator that controls the sampling and operation / stop of
The control circuit sets a measurement timing generated by the timing generation unit, cancels a low power consumption mode by an interrupt request signal from the threshold determination unit, and reads digital data. Received field strength signal measurement circuit. 4. The reception field strength signal measurement circuit for a wireless communication device according to claim 2, wherein the control circuit sets a threshold value used by the threshold value determination unit for determination. 4. The reception field strength signal measurement circuit for a wireless communication device according to claim 3, wherein the control circuit sets the number of data calculated by the average value calculation unit.

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