JPH07226708A - Radio receiver for plural channels - Google Patents

Abstract

PURPOSE:To suppress power consumption in the case of carrier sense and to extend a drive time by using a single channel local oscillator in the case of carrier sense and using a multi-channel local oscillator after an objective radio wave is received. CONSTITUTION:A high frequency signal received by an antenna 203 is mixed with a signal sent from a single channel local oscillation circuit 217 at a mixer circuit 219, the mixed signal is amplified by an intermediate frequency amplifier circuit 221, converted into a digital signal by a detection demodulation circuit 223 and the signal is processed by a data processing circuit 225. In this case, when the signal received by the processing circuit 225 is an objective signal, a control circuit 209 controls the power from a power supply circuit 211 to be supplied to a multi-channel local oscillator 213 and controls a switching circuit 227 to allow the circuit 227 to select a signal from the oscillator 213 to be fed to the mixer circuit 219. Furthermore, a channel of the oscillator 213 is selected based on a communication channel number sent from a transmitter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver having a plurality of receiving channels, and more particularly to a radio receiver having low power consumption.

[0002]

2. Description of the Related Art A wireless system is used in which a small wireless transceiver is used to transmit various kinds of data and control devices and the like based on the received data. The receiver used in such a system is generally driven by a battery, and intermittent drive reception is performed in order to reduce power consumption as much as possible and lengthen continuous operation time of the receiver. In the intermittent drive reception, first, it is checked (carrier sense) whether or not a target radio wave exists at a predetermined rate at a predetermined time interval. The reception operation is performed only when the radio wave is present and the radio wave is the target radio wave.

FIG. 3 is a block diagram showing an example of the configuration of a conventional radio receiver for receiving only a single channel. As shown in the figure, the wireless receiver 301 has an antenna 303, a receiving unit 305, a timer circuit 307, a control circuit 309, and a power supply circuit 311. The reception unit 305 includes a high frequency amplification circuit 313, a local oscillation circuit 315, a mixing circuit 317, an intermediate frequency amplification circuit 319, a detection / demodulation circuit 321, and a data processing circuit 123.

The timer circuit 307 activates the control circuit 309 every prescribed time. When the control circuit 309 is activated, power is supplied from the power supply circuit 311 to the receiving unit 305, and the receiving operation becomes possible. Further, since the local oscillator circuit 315 only needs to oscillate a single frequency, a crystal oscillator circuit having a simple structure and low power consumption is used.

The high frequency signal received by the antenna 303 is amplified by the high frequency amplifier circuit 313 and mixed by the mixing circuit 317.
Is mixed with the signal sent from the local oscillator circuit 315, converted into an intermediate frequency signal, and the intermediate frequency amplifier circuit 31
The signal is amplified in 9, converted into a digital signal by the detection / demodulation circuit 321 and processed by the data processing circuit 323.

However, in recent years, a large number of such wireless devices have been used, and there may be a case where there are a plurality of transmitter / receiver pairs within the range where radio waves reach each other. In this case, while one transceiver pair is communicating,
Other transceiver pairs cannot communicate. Therefore, the control channel and a plurality of communication channels are used to determine which communication channel is used for communication on the control channel, and communication is performed on the determined channel.

When communication is performed using a plurality of channels in this way, the local oscillator circuit 3 of the receiver 301 shown in FIG. 3 is used.
It is common practice to use a PLL (Phase Locked Loop) synthesizer 15 to oscillate a plurality of signals of different frequencies.

FIG. 4 is a block diagram showing the configuration of the PLL synthesizer. The oscillation wave output from the voltage control oscillator 401 is fed back to the phase detector 402, and the fluctuation of the oscillation frequency of the oscillation in the voltage control oscillator 401 is corrected. After that, the output signal from the phase detector 402 is removed by the low-pass filter 405 except the signal in the specified frequency band. Further, the fluctuation of the frequency of the oscillation wave in the voltage controlled oscillator 401 is corrected. In this way, an oscillating wave having a stable specified frequency can be transmitted. The time required for oscillation to stabilize (lock-up time) is several tens of milliseconds to several hundreds of milliseconds. Further, the PLL synthesizer consumes a large amount of power, and it is difficult for the small receiver having the limited battery capacity as described above to continue operating for a long time.

[0009]

As described above, in a conventional radio receiver having a plurality of communication channels, a PLL synthesizer or the like is used as a local oscillator, so that power consumption becomes large and a battery having a constant capacity is used. In this case, there is a problem that the driving time of the wireless receiver becomes short.

The present invention has been made in view of the above problems, and suppresses power consumption during carrier sensing.
An object of the present invention is to provide a multi-channel radio receiver capable of extending driving time.

[0011]

To achieve this object, a multi-channel radio receiver according to the present invention comprises an antenna for inducing a high frequency signal from an inputted radio wave and a first frequency signal oscillating signal. Local oscillator, a second local oscillator capable of oscillating a plurality of signals having different frequencies, a signal from the first local oscillator and a signal from the second local oscillator are selected and output. Signal switching means, mixing means for mixing the high frequency signal induced by the antenna and the signal from the signal switching means and outputting an intermediate frequency signal, and the signal switching means for carrier sensing is the first local part. The signal is controlled so as to output a signal from the oscillator, and when the target radio wave is received, power is supplied to the second local oscillator and the signal switching means is used by the second station. It is characterized by comprising a control means for outputting a signal from the oscillator.

[0012]

In the multi-channel radio receiver of the present invention, a single channel type local oscillator such as a crystal oscillator is used at the time of carrier sensing, and the PL after receiving the target radio wave.
A multi-channel type local oscillator such as an L synthesizer is used.

Therefore, power consumption during intermittent carrier sensing can be suppressed low while enabling reception by a plurality of channels.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a wireless transmitter for transmitting data to a multi-channel wireless receiver of the present invention.

The transmitter 101 has an antenna 103, a transmitter 105, a timer circuit 107, a control circuit 109, and a power supply circuit 111. The transmission unit 105 includes a message information setting circuit 113, a signal transmission circuit 115, a modulation transmission circuit 117, a local oscillation circuit 119, and a high frequency amplification circuit 121. The timer circuit 107 sends a signal to the control circuit 109 at regular time intervals. When a signal is input to the control circuit 109, power is supplied from the power supply circuit 111 to the transmitter 105.

The electronic message information setting circuit 113 sets the electronic message contents to be sent. This message content also includes channel number information of the communication channel. Then, in the signal transmission circuit 115, a header or the like for wireless communication is added to the data of the message content. Next, the modulation transmission circuit 1
At 17, the high frequency signal from the local oscillation circuit 119 is modulated by the signal from the signal transmission circuit 115. The modulated high frequency signal is high frequency amplified by the high frequency amplifier circuit 121 and sent out as a radio wave from the antenna 103. Figure 2
FIG. 3 is a block diagram showing a configuration of a multi-channel wireless receiver of the present invention. As shown in the figure, the multi-channel wireless receiver 201 has an antenna 203, a receiving unit 205, a timer circuit 207, a control circuit 209, a power supply circuit 211, and a multi-channel type local oscillator 213. The reception unit 205 includes a high frequency amplification circuit 215, a single channel type local oscillation circuit 217,
It has a mixing circuit 219, an intermediate frequency amplification circuit 221, a detection / demodulation circuit 223, a data processing circuit 225, and a switching circuit 227.

The timer circuit 207 sends a signal to the control circuit 209 at regular time intervals. When a signal is input to the control circuit 209 from the timer circuit 207, power is supplied from the power supply circuit 211 to the receiving unit 205 and the receiving operation can be performed.
A crystal oscillator circuit having a simple structure and low power consumption is used for the single-channel type local oscillator 217. Further, the multi-channel type local oscillator 213 uses a PLL synthesizer. Then, the data processing circuit 225
If the control circuit 209 determines that the control circuit 209 has received an instruction to communicate on a specific communication channel, the control circuit 209 controls so that the power from the power supply circuit 211 is also supplied to the multi-channel type local oscillator 213. Further, the switching circuit 227 includes a control circuit 209.
In accordance with the instruction of 1, the signal from the single-channel type local oscillator 217 or the signal from the multi-channel type local oscillator 213 is selected and supplied to the mixing circuit 219.

Next, the operation of the multi-channel radio receiver 201 having the above configuration will be described. In the initial state, the switching circuit 227 is the single-channel type local oscillation circuit 2
It is set to supply the signal from 17 to the mixing circuit 219. Then, each time the timer circuit 207 sends a signal to the control circuit 209 at regular time intervals, power is supplied to the receiving unit 205 to enter the receiving state. At this time, no power is supplied to the multi-channel type local oscillator 213.

That is, the high frequency signal received by the antenna 203 is amplified by the high frequency amplification circuit 215, mixed by the mixing circuit 219 with the signal sent from the single channel local oscillation circuit 217, and converted into an intermediate frequency signal. ,
The detection / demodulation circuit 2 is amplified by the intermediate frequency amplification circuit 221.
The data is converted into a digital signal by 23 and processed by the data processing circuit 225. At this time, when the signal received by the data processing circuit 225 is the target signal, the control circuit 209 first controls so that the power from the power supply circuit 211 is supplied to the multi-channel local oscillator 213. Further, the control circuit 209 controls the switching circuit 227 to control the multi-channel type local oscillator 21.
The signals are switched so that the signal No. 3 is supplied to the mixing circuit 219. Further, the channel of the multi-channel type local oscillator 213 is selected based on the communication channel number sent from the transmitter 101.

After that, the data transmitted from the transmitter 101 is transmitted through the selected channel and processed. When the series of data processing is completed, the data processing circuit 225 sends a data processing completion signal to the control circuit 209,
The control circuit 209 terminates the data reception process by receiving this signal, and thereafter shifts to the radio wave monitoring operation.
Therefore, at the time of carrier sense, the single-channel local oscillator 217 that consumes less power is driven, and after the target signal is received, the multi-channel local oscillator 213 configured by a PLL synthesizer or the like is driven, thereby performing The power consumption can be kept low.

[0022]

As described above, according to the multi-channel radio receiver of the present invention, a single-channel type local oscillator such as a crystal oscillator is used at the time of intermittent carrier sensing to receive a target radio wave. After that, power is supplied to a multi-channel type local oscillator such as a PLL synthesizer for use. Since the crystal oscillator rises faster than the PLL synthesizer, the time required for the carrier sense operation is shorter. Therefore, the carrier sense operation time can be shortened as compared with the conventional receiver using the PLL synthesizer even in the intermittent carrier sense. This makes it possible to reduce the power consumption during intermittent carrier sensing and extend the operable time of the receiver while enabling reception by a plurality of channels.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless transmitter for transmitting data to a multi-channel wireless receiver of the present invention.

FIG. 2 is a block diagram showing a configuration of a multi-channel wireless receiver of the present invention.

FIG. 3 is a block diagram showing an example of a configuration of a conventional wireless receiver.

FIG. 4 is a block diagram showing a configuration of a PLL synthesizer.

[Explanation of symbols]

 203 ... Antenna 205 ... Receiving part 209 ... Control circuit 211 ... Power supply circuit 213 ... Multi-channel type local oscillation circuit 217 ... Single channel type local oscillation circuit 219 ... Mixing circuit 227 ... Switching circuit

Claims (2)

[Claims] 1. An antenna for inducing a high frequency signal from an input radio wave, a first local oscillator for oscillating a signal of a single frequency, and a second local oscillator for oscillating a plurality of signals of different frequencies, A signal switching means for selecting and outputting one of a signal from the first local oscillator and a signal from the second local oscillator; and a high frequency signal induced by the antenna and a signal from the signal switching means. Mixing means for mixing signals with each other and outputting an intermediate frequency signal; and, when carrier sensing is performed, the signal switching means is controlled to output a signal from the first local oscillator, and when a target radio wave is received, Control means for supplying power to the second local oscillator and controlling the signal switching means to output a signal from the second local oscillator. A multi-channel radio receiver to collect. 2. The first local oscillator is a single-channel type local oscillator using a crystal oscillator, and the second local oscillator is a multi-channel type local oscillator using a phase-locked loop synthesizer. Multi-channel radio receiver.