JP5632653B2 - Wireless transceiver - Google Patents

Description

  The present invention relates to a wireless transceiver.

  2. Description of the Related Art Conventionally, various superheterodyne wireless transmitters / receivers that convert a radio frequency to a relatively low frequency (intermediate frequency) for amplification and detection have been provided. For example, the wireless receiver described in Patent Document 1 includes a local oscillator that outputs a signal (that is, a local oscillation signal) having a frequency (local oscillation frequency) that is an integral multiple of the frequency of the input signal (reference oscillation signal). The received signal (RF signal) received by the antenna and the local oscillation signal output from the local oscillator are mixed by a mixer, and converted to a signal (intermediate frequency signal) having a lower frequency (intermediate frequency) than the RF signal. ing. Various wireless transceivers using a phase locked loop circuit as a local oscillator are also provided.

JP 2010-28331 A

  By the way, of the two types of local oscillators described above, the local oscillator using the frequency multiplier circuit has an advantage that it consumes less power than the local oscillator using the PLL circuit. On the other hand, the former local oscillator has an advantage that the frequency variable range is wide compared to the latter local oscillator. In general wireless transceivers, a local oscillator using a PLL circuit is often adopted in consideration of a wide frequency variable range. On the other hand, when the PLL circuit is used, the power consumption increases as compared with the case where the frequency multiplication circuit is used. In particular, in wireless transceivers installed in devices powered by batteries, the advantage is that the battery life can be extended by adopting the former local oscillator (local oscillator using a frequency multiplier) with low power consumption. There is.

  The present invention has been made in view of the above circumstances, and an object thereof is to secure a variable frequency range while reducing power consumption in a local oscillator.

A radio transceiver according to the present invention includes a local oscillator that oscillates at a predetermined local oscillation frequency, and a mixer that mixes a local oscillation signal of the local oscillation frequency output from an output end of the local oscillator and a radio signal received by an antenna A modulation circuit that modulates the local oscillation signal to generate a radio signal, a receiving state in which the output terminal of the local oscillator is connected to the mixer, and the output terminal that is connected to the antenna without passing through the mixer A transmission / reception switching unit that selectively switches between a transmittable state to be transmitted and the local oscillator, a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and an output terminal of the reference oscillation unit A first frequency conversion unit and a second frequency conversion unit for converting a reference oscillation signal of the reference oscillation frequency output from the first oscillation unit into the local oscillation signal; and an output terminal of the reference oscillation unit. The first input state connected to the input terminal of the first frequency conversion unit and the second input state where the output terminal of the reference oscillation unit is connected to the input terminal of the second frequency conversion unit A first switching unit for switching to the first output state, the first output state of connecting the output terminal of the local oscillator to the output terminal of the first frequency converter, and the output terminal of the local oscillator of the second frequency converter. A second switching unit that selectively switches the second output state connected to the output terminal in conjunction with the switching operation of the first switching unit, wherein the second frequency conversion unit The phase locked loop circuit includes a controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency converter includes a frequency multiplier circuit that consumes less power than the phase locked loop circuit. The local oscillator is connected to an external power source A bypass capacitor for grounding the power supply terminal of the voltage controlled oscillator in an alternating manner, an open / close unit for opening and closing the connection between the bypass capacitor and the external power supply or the power supply terminal, and an inrush current flowing from the external power supply to the bypass capacitor A current-limiting resistor for limiting the current and a short-circuit portion connected in parallel with the current-limiting resistor, and the open / close portion includes the second switching state when the first switching portion is switched to the second input state. Only when the switching unit is switched to the second output state, the bypass capacitor and the external power source or the power supply terminal are connected, and the short-circuit unit includes the open / close unit and the bypass capacitor and the external power source. Or after connecting the said power supply terminal, the said external power supply and the said power supply terminal are short-circuited, It is characterized by the above-mentioned .
A radio transceiver according to the present invention includes a local oscillator that oscillates at a predetermined local oscillation frequency, and a mixer that mixes a local oscillation signal of the local oscillation frequency output from an output end of the local oscillator and a radio signal received by an antenna A modulation circuit that modulates the local oscillation signal to generate a radio signal, a receiving state in which the output terminal of the local oscillator is connected to the mixer, and the output terminal that is connected to the antenna without passing through the mixer A transmission / reception switching unit that selectively switches between a transmittable state to be transmitted and the local oscillator, a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and an output terminal of the reference oscillation unit A first frequency conversion unit and a second frequency conversion unit for converting a reference oscillation signal of the reference oscillation frequency output from the first oscillation unit into the local oscillation signal; and an output terminal of the reference oscillation unit. The first input state connected to the input terminal of the first frequency conversion unit and the second input state where the output terminal of the reference oscillation unit is connected to the input terminal of the second frequency conversion unit A first switching unit for switching to the first output state, the first output state of connecting the output terminal of the local oscillator to the output terminal of the first frequency converter, and the output terminal of the local oscillator of the second frequency converter. A second switching unit that selectively switches the second output state connected to the output terminal in conjunction with the switching operation of the first switching unit, wherein the second frequency conversion unit It consists of a phase-locked loop circuit having a controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency converter consists of a frequency multiplier that consumes less power than the phase-locked loop circuit. Furthermore, the local oscillator is A local oscillation signal with a local oscillation frequency for reception different from the radio frequency of the signal and a local oscillation signal with a local oscillation frequency for transmission equal to the radio frequency are selected and output, the local area for reception The local oscillation signal having a relatively high frequency selected from the oscillation signal and the local oscillation signal for transmission is converted and output to the first frequency conversion unit, and the local unit having the relatively low frequency is selected. The oscillation signal is converted and output to the second frequency converter.
A radio transceiver according to the present invention includes a local oscillator that oscillates at a predetermined local oscillation frequency, and a mixer that mixes a local oscillation signal of the local oscillation frequency output from an output end of the local oscillator and a radio signal received by an antenna A modulation circuit that modulates the local oscillation signal to generate a radio signal, a receiving state in which the output terminal of the local oscillator is connected to the mixer, and the output terminal that is connected to the antenna without passing through the mixer A transmission / reception switching unit that selectively switches between a transmittable state to be transmitted and the local oscillator, a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and an output terminal of the reference oscillation unit A first frequency conversion unit and a second frequency conversion unit for converting a reference oscillation signal of the reference oscillation frequency output from the first oscillation unit into the local oscillation signal; and an output terminal of the reference oscillation unit. The first input state connected to the input terminal of the first frequency conversion unit and the second input state where the output terminal of the reference oscillation unit is connected to the input terminal of the second frequency conversion unit A first switching unit for switching to the first output state, the first output state of connecting the output terminal of the local oscillator to the output terminal of the first frequency converter, and the output terminal of the local oscillator of the second frequency converter. A second switching unit that selectively switches the second output state connected to the output terminal in conjunction with the switching operation of the first switching unit, wherein the second frequency conversion unit It consists of a phase-locked loop circuit having a controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency converter consists of a frequency multiplier that consumes less power than the phase-locked loop circuit. , The first switching unit and the second switching unit A switching control unit for controlling the switching unit, wherein the switching control unit switches the first switching unit to the first input state when the transmission / reception switching unit is switched to a receivable state; The first switching unit is switched to the second input state only when the reception signal output from the mixer is not normally demodulated in a state where the second switching unit is switched to the first output state. The second switching unit is switched to the second output state.

  In this wireless transceiver, it is preferable that the reference oscillation unit selectively switches and outputs a plurality of types of the reference oscillation signals having different reference oscillation frequencies.

  In this wireless transceiver, the local oscillator opens and closes a bypass capacitor that grounds the power supply terminal of the voltage controlled oscillator connected to an external power supply in an AC manner, and the connection between the bypass capacitor and the external power supply or the power supply terminal. An opening / closing unit that is configured to switch the first switching unit to the second input state and the second switching unit to the second output state. It is preferable to connect the bypass capacitor and the external power supply or the power supply terminal.

  In this wireless transceiver, it is preferable that the local oscillator includes a current limiting resistor that limits an inrush current flowing from the external power source to the bypass capacitor.

  In this wireless transceiver, the local oscillator includes a short-circuit portion connected in parallel with the current limiting resistor, and the short-circuit portion connects the bypass capacitor and the external power source or the power supply terminal. It is preferable to short-circuit the external power supply and the power supply terminal later.

  In this radio transceiver, the local oscillator selects a local oscillation signal having a reception local oscillation frequency different from the radio frequency of the radio signal and a local oscillation signal having a transmission local oscillation frequency equal to the radio frequency. The local oscillation signal having a relatively higher frequency selected from the local oscillation signal for reception and the local oscillation signal for transmission is converted into the first frequency conversion unit. Preferably, the local oscillation signal having a relatively low frequency is output to the second frequency conversion unit.

  In this wireless transceiver, comprising a switching control unit for controlling the first switching unit and the second switching unit, the switching control unit, when the transmission / reception switching unit is switched to a receivable state, Only when the received signal output from the mixer is not demodulated normally in a state where the first switching unit is switched to the first input state and the second switching unit is switched to the first output state. Preferably, the first switching unit is switched to the second input state and the second switching unit is switched to the second output state.

  In this wireless transceiver, it is preferable that the switching control unit fixes the state of the first and second switching units to the state at the elapse of the predetermined period after the predetermined period has passed in the receivable state. .

  In this radio transceiver, when the transmission / reception switching unit is switched to a receivable state, the local oscillator performs an intermittent operation that repeats an operation period and a pause period at a predetermined cycle, and the switching control unit Preferably, at the start of the period, the first switching unit is switched to the first input state and the second switching unit is switched to the first output state.

  In this wireless transceiver, the switching control unit switches the first switching unit to the second input state and the number of times of switching the second switching unit to the second output state exceeds a predetermined number. Thereafter, it is preferable that the first switching unit is switched to the second input state and the second switching unit is switched to the second output state at the start of the operation period.

In this wireless transceiver, the reference oscillation unit selectively switches and outputs a plurality of types of the reference oscillation signals having different reference oscillation frequencies.
The first frequency converter has a plurality of multiplication circuits having different multiplication numbers from each other,
The switching control unit is configured so that a reception signal output from the mixer is normal when the first switching unit is switched to the first input state and the second switching unit is switched to the first output state. If the received signal is not demodulated normally in all combinations while sequentially changing the combination of the reference oscillation frequency of the reference oscillation signal and the multiplication number of the multiplication circuit without changing the local oscillation frequency Preferably, the first switching unit is switched to the second input state and the second switching unit is switched to the second output state.

  In this wireless transceiver, the switching control unit has a clock for measuring time, and when the time measured by the clock is in a daytime time zone, the first switching unit is set to the second input state. And the second switching unit is switched to the second output state, and when the time is a night time zone, the first switching unit is switched to the first input state and the second input state is switched. It is preferable to switch the switching unit to the first output state.

  The radio transceiver according to the present invention has an effect that a variable frequency range can be ensured while reducing power consumption in the local oscillator.

It is a block diagram which shows embodiment of this invention. It is a principal part circuit diagram of the local oscillator in the same as the above. It is another principal part circuit diagram of the local oscillator in the same as the above. (a), (b) is another principal part circuit diagram of the local oscillator in the same as the above. It is a system configuration | structure figure of the radio | wireless communication apparatus and radio | wireless communications system which mount same as the above. It is a system configuration | structure figure of the equipment control system using the radio | wireless transmitter and radio | wireless receiver which mount same as the above.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the wireless transceiver of this embodiment includes a local oscillator 1, an antenna 2, an RF filter 3, a low noise amplifier 4, a mixer 5, an intermediate frequency filter 6, and an intermediate frequency. An amplifier (IF amplifier) 7, a demodulation unit 8, a transmission unit 9, an antenna switching unit 10, a transmission / reception switching unit 11, and a control unit 12 are provided. Here, in the radio transceiver according to the present embodiment, a frequency modulation (frequency shift keying: FSK) method is adopted as a modulation method, and a radio signal transmitted from the antenna 2 is divided by a programmable frequency divider 32 described later. Modulation processing is performed by changing the ratio m according to the modulation signal, and the radio signal received by the antenna 2 is converted to an intermediate frequency lower than the frequency of the radio signal (radio frequency) and then demodulated by the demodulator 8. Do. However, the modulation processing method is not limited to the above-described modulation processing, and for example, a method of mixing a signal (local oscillation signal) output from the local oscillator 1 and the modulation signal by the transmission unit 9 may be used. Alternatively, a method of changing the capacitance of the variable capacitance unit configured by the switched capacitor or the varicap diode to be performed according to the modulation signal may be used. The modulation method is not limited to the frequency modulation method, and may be a phase modulation (phase shift keying) method such as BPSK, for example.

  The local oscillator 1 includes a reference oscillation unit 20, a multiplication unit 21, a PLL unit 22, a first switching unit 23, and a second switching unit 24. The reference oscillation unit 20 oscillates at a predetermined reference oscillation frequency fx lower than the radio frequency and outputs a reference oscillation signal. However, the reference oscillating unit 20 has a variable capacitance unit (not shown) composed of a switched capacitor or a varicap diode (not shown), and the control unit 12 changes the capacitance of the variable capacitance unit to thereby change the reference oscillation frequency. fx can be selected from a plurality of frequencies fx1, fx2, fx3,... The multiplier 21 corresponds to a first frequency converter, and converts the reference oscillation signal output from the reference oscillation unit 20 into a signal (local oscillation signal) having a local oscillation frequency fy. The PLL unit 22 corresponds to a second frequency conversion unit, and similarly converts the reference oscillation signal output from the reference oscillation unit 20 into a local oscillation signal having a local oscillation frequency fy. The first switching unit 23 includes a first input state in which the output end of the reference oscillation unit 20 is connected to the input end of the multiplication unit 21, and a first input state in which the output end of the reference oscillation unit 20 is connected to the input end of the PLL unit 22. It is alternatively switched between two input states. The second switching unit 24 includes a first output state in which the output end of the local oscillator 1 is connected to the output end of the multiplier unit 21, and a second output state in which the output end of the local oscillator 1 is connected to the output end of the PLL unit 22. The output state is selectively switched.

  The multiplier 21 uses a nonlinearity of input / output characteristics of a transistor or the like, for example, a signal (that is, a local oscillation signal) having a frequency (local oscillation frequency fy) that is an integral multiple of the frequency fx of the input signal (reference oscillation signal). It consists of a frequency multiplication circuit that outputs. However, since such a multiplier 21 is well known in the art, a detailed description of the configuration and operation is omitted. Further, a conventionally known delay locked loop circuit may be used as the multiplier 21.

  The PLL unit 22 is well known in the art and includes a voltage controlled oscillator 30, a 1 / n frequency divider 31, a programmable frequency divider 32, a phase comparator 33, a loop filter 34, and a charge pump 35. Yes. The 1 / n frequency divider 31 divides the reference oscillation signal by 1 / n (n is a positive integer). The programmable frequency divider 32 divides the output signal of the voltage controlled oscillator 30 by 1 / m (m is a positive integer or fraction different from n). The phase comparator 33 detects the phase difference between the two frequency dividers 31 and 32 and outputs a signal corresponding to the phase difference. The charge pump 35 charges and discharges charges according to the signal output from the phase comparator 33. The loop filter 34 smoothes a signal output in accordance with charge / discharge of the charge pump 35. Then, by controlling the voltage controlled oscillator 30 with the DC signal output from the loop filter 34, a local oscillation signal having a local oscillation frequency fy (= m / n × fx) is output from the PLL unit 22. Here, the frequency division numbers n and m of the two frequency dividers 31 and 32 can be set to arbitrary integer values (where m can also be a fraction) by the control unit 12, and the frequency division numbers n and m Is set to an appropriate integer value (where m can be a fraction), the local oscillation frequency fy of the local oscillator 1 can be changed.

  Here, when the multiplication unit 21 having the above-described configuration is compared with the PLL unit 22, the power consumption is less in the multiplication unit 21 than in the PLL unit 22, and the variable range of the local oscillation frequency fy is larger than that in the multiplication unit 21. The part 22 is wider.

  The voltage control oscillator 30 of the PLL unit 22 is supplied with operation power from an external power supply (system power supply) Vcc, and a switch SW1 for turning on / off the power supply from the system power supply Vcc to the voltage control oscillator 30 is provided. Is provided. That is, when the switch SW1 is turned off by the control unit 12, the power supply terminal is disconnected from the system power supply Vcc and the voltage controlled oscillator 30 is stopped. When the switch SW1 is turned on, the power supply terminal is connected to the system power supply Vcc. The voltage controlled oscillator 30 operates. Here, in order to stabilize the power supply voltage, a bypass capacitor C1 that grounds the power supply terminal in an alternating manner is connected to the power supply terminal of the voltage controlled oscillator 30.

  The first switching unit 23 includes a common terminal 23c connected to the output terminal of the reference oscillation unit 20, a switching terminal 23a connected to the input terminal of the multiplication unit 21, and an input terminal (1 / n minutes) of the PLL unit 22. It switches alternatively to the switching terminal 23b connected to the input terminal of the peripheral 31). The second switching unit 24 includes a common terminal 24c connected to the common terminal 11c of the transmission / reception switching unit 11, a switching terminal 24a connected to the output terminal of the multiplication unit 21, and an output terminal (voltage control) of the PLL unit 22. It is alternatively switched to the switching terminal 24b connected to the output terminal of the oscillator 30). Further, the transmission / reception switching unit 11 selectively switches the common terminal 11 c between a switching terminal 11 a connected to the input terminal of the mixer 5 and a switching terminal 11 b connected to the input terminal of the transmission unit 9. At substantially the same time, the antenna switching unit 10 includes a common terminal 10 c connected to the antenna 2, a switching terminal 10 a connected to the input terminal of the RF filter 3, and a switching terminal 10 b connected to the output terminal of the transmission unit 9. Switch alternatively. The antenna switching unit 10, the transmission / reception switching unit 11, and the first and second switching units 23 and 24 are all controlled to be switched by the control unit 12. The switching control by the control unit 12 switches the first switching unit 23 and the second switching unit 24 substantially simultaneously and controls the antenna switching unit 10 and the transmission / reception switching unit 11 almost simultaneously. However, from the viewpoint of preventing an unexpected malfunction, the first switching unit 23, the second switching unit 24, the antenna switching unit 10, and the transmission / reception switching unit 11 are switched at substantially the same time, or It is desirable to switch the antenna switching unit 10 and the transmission / reception switching unit 11 substantially simultaneously after switching control of the first switching unit 23 and the second switching unit 24 substantially simultaneously.

  The transmission unit 9 is composed of an amplifier that amplifies the modulated radio signal (RF signal) output from the local oscillator 1, amplifies the radio signal (RF signal) output from the local oscillator 1, and sends it to the antenna switching unit 10. Output. A radio signal input via the antenna switching unit 10 is radiated from the antenna 2 as a radio wave. Since such a transmitter 9 is well known in the art, a detailed description of the configuration and operation is omitted.

  Here, the local oscillator 1 includes a local oscillation signal for reception (frequency equal to the difference between the radio frequency and the intermediate frequency) lower than the radio frequency of the radio signal, and a local oscillation frequency for transmission equal to the radio frequency. The local oscillation signal is selected and output. In the wireless transceiver according to the present embodiment, the local oscillation signal having a relatively high frequency selected from the local oscillation signal for reception and the local oscillation signal for transmission is used as the first frequency conversion unit (multiplication frequency). 21), and the local oscillation signal having a relatively lower frequency is converted and output to the second frequency converter (PLL unit 22). For example, a local oscillation signal for reception when the frequency of receiving a radio signal (including a case where a standby operation is performed to receive a radio signal; the same applies hereinafter) is higher than the frequency of transmitting a radio signal. The power consumption can be reduced by causing the multiplier unit 21 to convert and output the signal as compared to the PLL unit 22 for converting the output. On the contrary, when the frequency of transmitting the radio signal is higher than the frequency of receiving the radio signal, the power consumption is higher than that of the PLL unit 22 by converting and outputting the local oscillation signal for transmission to the multiplier unit 21. Can be reduced. However, the conditions for selectively using the multiplier 21 and the PLL unit 22 are not limited to the time of reception and the time of transmission. For example, as described later, when a plurality of frequency channels can be selected as the radio frequency, when the default (initial state) frequency channel is selected, the multiplier 21 is used as the frequency converter of the local oscillator 1, and the default When a frequency channel other than those is selected, the power consumption can be similarly reduced by using the PLL unit 22 as the frequency conversion unit of the local oscillator 1.

  The radio transceiver according to the present embodiment is used for a certain type of radio communication device Xj (j is a natural number) as shown in FIG. 5, for example. A certain type of wireless communication device Xj is at least one of various environmental measurement sensors Sk (k is a natural number unrelated to j) such as an optical sensor S1, a thermal sensor S2, a chemical sensor S3, a pressure sensor S4,. It has. These wireless communication devices Xj sense changes in the surrounding environment of the installation location while attached to the ceiling or wall surface, and send wireless signals to other wireless communication devices Xj when changes in the surrounding environment are detected. It is something to be informed. Here, the types of the environmental measurement sensors Sk may be unified, or may be different for each wireless communication device Xj. For example, the wireless communication device X1 alone activates its own wireless transmitter / receiver (wireless transmitter / receiver of this embodiment) at a certain intermittent reception interval, and originates from any of the other wireless communication devices X2, X3, X4,. If the first-type wireless signal Sig1 having a finite time length cannot be received, the wireless communication device X1 immediately stops its own wireless transceiver to prevent battery consumption. On the other hand, if the first type of radio signal Sig1 can be received, this not only represents the fact that the first type of radio signal Sig1 can be received, but also the first type of radio signal Sig1 is transmitted to other unspecified many radio communication devices. A second type of radio signal Sig2 indicating transfer to X2, X3, X4,... Is transmitted from the radio transmitter / receiver of the own device (wireless communication device X1). As illustrated in FIG. 5, each of these wireless communication devices Xj includes at least one of a display notification unit X100 that makes a human sense of vision and a sound notification unit X101 that appeals to hearing, and any of the wireless communication devices When Xj (wireless communication device X1 in FIG. 5) detects a surrounding abnormality, the wireless communication device Xj activates the display notification unit X100 or the sound notification unit X101 by itself and notifies the occurrence of the abnormality to the surroundings. A kind of radio signal Sig1 is transmitted. Then, all other wireless communication devices (only the wireless communication device X2 closest to the wireless communication device X1 in FIG. 5) that received the first type wireless signal Sig1 receive the first type wireless signal Sig1. Analyzing the address and transferring the second type radio signal Sig2 to other radio communication devices that have not received the first type radio signal Sig1 (X3 and X4 other than the radio communication devices X1 and X2 in FIG. 5) To do. In the wireless communication device X3, it is impossible to know whether or not the wireless communication device X4 has received the second type of wireless signal Sig2 from the wireless communication device X2, so that the wireless communication device X3 that has received the second type of wireless signal Sig2 continues. The second type of radio signal Sig2 is transferred to the radio communication device X4. As a result, not only the first unit (wireless communication device X1) that senses the occurrence of an abnormality, but also all the wireless communication devices registered in advance (wireless communication devices X1, X2, X3, X4) Abnormality can be notified.

  More specifically, the operation of the wireless transceiver according to the present embodiment will be described in association with the operation of the above-described wireless communication device.

  First, when any environment change around the installation location is not detected in any wireless communication device, the control unit 12 repeatedly counts the intermittent reception interval by a timer (not shown), and the counting of the intermittent reception interval is completed. Each time it is started, the wireless transceiver is activated in a receivable state. That is, when the counting of the intermittent reception interval is completed, the control unit 12 switches and connects the common terminal 10c of the antenna switching unit 10 to the switching terminal 10a on the RF filter 3 side and the common terminal 11c of the transmission / reception switching unit 11 on the mixer 5 side. A switching connection is made to the switching terminal 11a. Further, the control unit 12 switches and connects the common terminal 23c of the first switching unit 23 to the switching terminal 23a connected to the input terminal of the multiplication unit 21, and the multiplication unit 21 connects the common terminal 24c of the second switching unit 24. The switching connection is made to the switching terminal 24a connected to the output terminal. At this time, the control unit 12 turns off the switch SW1, disconnects the power supply terminal of the voltage controlled oscillator 30 from the system power supply Vcc, and stops the PLL unit 22.

  In this receivable state, the IF amplifier 7 amplifies the intermediate frequency signal (IF signal) and simultaneously outputs an RSSI (reception signal strength display) signal indicating the signal strength of the input signal (IF signal before amplification) to the control unit 12. . If the RSSI signal is less than a predetermined threshold, the control unit 12 determines that the radio wave received by the antenna 2 is not the desired wave (radio wave transmitted from another wireless communication device), and immediately turns on the wireless transceiver. Stop. On the other hand, if the RSSI signal is equal to or greater than the threshold value, the control unit 12 determines that the received radio wave is highly likely to be a desired wave, and operates the radio transceiver as it is to demodulate the demodulation unit 8.

  When the radio signal demodulated by the demodulator 8 is the first type radio signal transmitted from another radio communication device, the controller 12 connects the common terminal 10c of the antenna switching unit 10 to the transmitter 9 side. The switching terminal 10b is switched and connected, and the common terminal 11c of the transmission / reception switching unit 11 is switched and connected to the switching terminal 11b on the transmission unit 9 side. Further, the control unit 12 switches and connects the common terminal 23 c of the first switching unit 23 to the switching terminal 23 b connected to the input terminal of the PLL unit 22, and also connects the common terminal 24 c of the second switching unit 24 to the PLL unit 22. Is switched to the switching terminal 24b connected to the output terminal. Furthermore, the control unit 12 turns on the switch SW1, connects the power supply terminal of the voltage controlled oscillator 30 to the system power supply Vcc, and operates the PLL unit 22.

  Then, the control unit 12 encodes a transmission frame including a signal indicating that the first type radio signal to be transmitted to another radio communication device is transmitted, and the local oscillation signal power is generated by the PLL unit 22 of the local oscillator 1. Is modulated by the frame to generate a signal for wireless transmission, amplified by the transmission unit 9, and then output to the antenna 2 via the antenna switching unit 10. As a result, the second type radio signal is transmitted from the antenna 2.

  When the wireless communication device receives intermittently, the power consumption can be reduced by operating the first frequency converter (multiplier 21) as the frequency converter of the local oscillator 1. On the other hand, when the wireless communication device transmits the first or second type of radio signal, the second frequency conversion unit (PLL unit 22) is selected as the frequency conversion unit of the local oscillator 1 as described above. Since it operates as a modulation circuit, it is possible to cover frequencies (radio frequencies) that cannot be handled by the multiplier 21. As a result, it is possible to secure a variable frequency range while reducing power consumption in the local oscillator 1. That is, in the above-described wireless communication system, when the frequency at which the wireless transceiver of each wireless communication device Xj operates in a receivable state is compared with the frequency at which it operates in a transmittable state, the frequency at which it operates in a receivable state is better. Since it is considered to be overwhelmingly high, it is possible to reduce power consumption by selecting the multiplier 21 in a receivable state as described above. On the other hand, by selecting the PLL unit 22 in the transmittable state, a local oscillation frequency selection range (variable range) is secured, and transmission at a desired radio frequency is possible.

  As described above, it is desirable that the frequency (radio frequency) of the radio wave used by the radio communication device can be appropriately selected from a plurality of radio frequencies (frequency channels) according to the environment of the installation location. In order to change the frequency channel, it is necessary to change the local oscillation frequency fy of the local oscillator 1 according to the frequency channel. As described above, the PLL unit 22 can easily change the local oscillation frequency fy by adjusting the frequency division numbers j and k. However, the local oscillation frequency fy is changed by adjusting the multiplication number of the multiplication unit 21. This is not as easy as adjusting the frequency division numbers j and k of the PLL unit 22.

  Therefore, the reference oscillation unit 20 according to the present embodiment is provided with a variable capacitance unit (not shown) configured by a switched capacitor or a varicap diode, and the control unit 12 changes the capacitance of the variable capacitance unit so that the reference oscillation unit 20 is changed. The 20 reference oscillation frequencies fx can be selected from a plurality of frequencies fx1, fx2, fx3,..., And the local oscillation frequency fy can be easily changed while the multiplication number of the multiplication unit 21 is fixed. Therefore, even when the frequency channel of the radio frequency can be changed, the multiplier 21 can be used as the frequency converter of the local oscillator 1 in the receivable state, and the PLL unit 22 is used in the receivable state. Since this is not necessary, the power consumption of the wireless transceiver (local oscillator 1) can be reduced.

  By the way, when the power supply to the local oscillator 1 is collectively turned on / off when the wireless transmitter / receiver is activated at the intermittent reception interval and intermittently received as described above, the power supply terminal of the voltage controlled oscillator 30 of the PLL unit 22 Each time, a charging current flows through the bypass capacitor C1 connected to, and wasteful power is consumed. However, in the present embodiment, the connection between the bypass capacitor C1 and the system power supply Vcc is opened and closed by the opening / closing unit (switch SW1), and the control unit 12 is used only when the PLL unit 22 is used as the frequency conversion unit of the local oscillator 1. Closes (turns on) the switch SW1. For this reason, when the PLL part 22 is unnecessary, it is possible to prevent the bypass capacitor C1 from being charged and discharged and wasteful power consumption.

  As shown in FIG. 2, another switch SW2 is added between the power supply terminal of the voltage controlled oscillator 30 and the bypass capacitor C1, and the switch is provided between the power supply terminal of the voltage controlled oscillator 30 and the system power supply Vcc. The two switches SW1 and SW2 may be turned on / off together with SW1.

  Further, when the switch SW1 (or switch SW2) is closed and the bypass capacitor C1 is connected to the system power supply Vcc, an inrush current (charge current) flows, and the voltage of the system power supply Vcc temporarily decreases. Therefore, as shown in FIG. 3, a current limiting resistor R is connected between the bypass capacitor C1 and the system power source Vcc, and the inrush current is limited by the current limiting resistor R to reduce a temporary decrease in the voltage of the system power source Vcc. It is desirable to do.

  However, in a steady state after the inrush current stops flowing, useless power is consumed by the current limiting resistor R and the voltage applied to the power supply voltage of the voltage controlled oscillator 30 is reduced. As shown, it is desirable to provide a short circuit (switch SW3) that short-circuits the system power supply Vcc and the power supply terminal of the voltage controlled oscillator 30. In this case, the controller 12 closes the switch SW1 while the switch SW3 is open, and then limits the inrush current with the current limiting resistor R (see FIG. 4A), and then opens the switch SW1 to open the current limiting resistor. R is separated in a circuit manner (see FIG. 4B). As a result, since no steady-state current flows through the current limiting resistor R, wasteful power consumption and voltage drop can be avoided. However, the switch SW1 may remain closed.

  By the way, the condition for switching the frequency converter in the local oscillator 1 from the multiplier 21 to the PLL unit 22 is not limited to the above-described reception and transmission. As described above, the multiplying unit 21 uses a non-linearity or generates a local oscillation signal by multiplying the reference oscillation frequency by an integer using a delay locked loop circuit. Therefore, compared to the local oscillation signal output from the PLL unit 22, the local oscillation signal output from the multiplication unit 21 includes an unnecessary frequency component that is an integral multiple of the reference oscillation frequency in addition to the desired local oscillation frequency. Many are included. Therefore, when the multiplication unit 21 is used as the frequency conversion unit of the local oscillator 1, it is highly likely that a radio wave (interference wave) having a frequency different from that of the radio wave (radio signal) that the user wants to receive is received. (Specifically, it is easily affected by an interference wave including a frequency component of an integer multiple of the reference oscillation frequency ± intermediate frequency). On the other hand, the PLL unit 22 has an advantage that it is less susceptible to the interference wave than the multiplier unit 21 because unnecessary frequency components included in the oscillation frequency after frequency conversion are relatively small. However, when a battery is used as a power source as in the above-described wireless communication device, if a PLL circuit is used as the frequency converter of the local oscillator, the battery life is shortened compared to when a multiplier circuit is used.

  Therefore, the control unit 12 switches the first switching unit 23 to the second input state and the second switching only when the reception signal (IF signal) output from the mixer 5 is not normally demodulated by the demodulation unit 8. The unit 24 may be switched to the second output state. Specifically, when the RSSI signal is equal to or greater than the threshold value and the demodulator 8 cannot synchronize the received signal (IF signal), the radio signal can be normally received due to the influence of the interference wave. Therefore, the control unit 12 may switch the frequency conversion unit in the local oscillator 1 from the multiplication unit 21 to the PLL unit 22 by switching control of the first and second switching units 23 and 24. In this way, it is possible to make the battery less susceptible to interference waves while extending the battery life.

  Here, when switching from the multiplication unit 21 to the PLL unit 22 during reception, the time until the circuit operation of the PLL unit 22 becomes stable cannot be received normally. On the other hand, if the intensity of the interference wave in the use environment of the wireless transceiver (installation environment of the wireless communication device) is high, the frequency conversion unit of the local oscillator 1 is frequently switched from the multiplication unit 21 to the PLL unit 22. If the intensity of the disturbing wave is low, it can be considered that the signal can be normally received even if the multiplier 21 is used in the frequency converter of the local oscillator 1.

  Therefore, the control unit 12 performs the above-described switching control on the first and second switching units 23 and 24 for a predetermined period from the start of use of the wireless transceiver (the start of operation of the wireless communication system by the wireless communication device group). After the predetermined period has passed, the state of the first and second switching units 23 and 24 may be fixed to the state at the elapse of the predetermined period. In addition, the control unit 12 switches from the multiplier unit 21 to the PLL unit 22 during reception, and checks whether or not reception is possible by switching from the PLL unit 22 to the multiplier unit 21 after a certain time (for example, several hours) has elapsed. If reception is possible, the multiplier 21 is used. In this case, after the number of times the control unit 12 switches the first switching unit 23 to the second input state and switches the second switching unit 24 to the second output state exceeds a predetermined number, the intermittent reception is performed. At the start, the first switching unit 23 may be switched to the second input state and the second switching unit 24 may be switched to the second output state. In this way, when used in an environment where the influence of the interference wave is small, the life of the battery can be extended by using only the multiplier 21 for the frequency converter of the local oscillator 1. On the other hand, when used in an environment where the influence of the interference wave is great, the radio signal can be received normally and quickly by using only the PLL unit 22 as the frequency conversion unit of the local oscillator 1.

  By the way, it is generally considered that the influence of jamming waves is greater in the daytime than in the nighttime. Therefore, a clock that counts the time is provided in the control unit 12, and when the time measured by the clock is in the daytime time period, the first switching unit 23 is switched to the second input state and the first switching unit 23 is switched to the second input state. The second switching unit 24 is switched to the second output state, and when the time is a night time zone, the first switching unit 23 is switched to the first input state and the second switching unit 24 is switched to the first output state. You may switch to the state. In this way, when used in a time zone (nighttime) in which the influence of the interference wave is small, it is possible to extend the life of the battery by using only the frequency multiplier 21 for the frequency converter of the local oscillator 1. . On the other hand, when used in a time zone (daytime) when the influence of the interference wave is large, the radio signal can be received normally and quickly by using only the PLL unit 22 as the frequency conversion unit of the local oscillator 1.

  Further, the reference oscillation unit 20 is configured to selectively switch and output a plurality of types of reference oscillation signals having different reference oscillation frequencies fx1, fx2,... And the first frequency conversion unit is multiplied by each other. It consists of multiple multiplier circuits with different numbers. When the control unit 12 switches the first switching unit 23 to the first input state and the second switching unit 24 switches to the first output state, the received signal is not demodulated normally. The combination of the reference oscillation frequency fxi (i = 1, 2,...) Of the reference oscillation signal and the multiplication number of the multiplication circuit may be sequentially changed without changing the frequency fy.

  For example, when the local oscillation frequency fy is desired to be 420 MHz, the reference oscillation frequency fx1 = 52.5 MHz multiplied by 8 and the reference oscillation frequency fx2 = 70 MHz multiplied by 6 may be used in combination. In the former case, it is easily affected by an interference wave of an integer multiple of ± 52.5 MHz ± intermediate frequency, whereas in the latter case, it is easily affected by an interference wave of an integer multiple of ± 70 MHz ± intermediate frequency. In other words, since the frequencies of the disturbing waves that are easily affected by each other are different, the influence of the disturbing waves is reduced by selecting a combination of the reference oscillation frequency and the multiplication number that is not easily affected by the existing disturbing wave frequencies. It becomes possible to do.

  Thus, there are cases where the received signal can be received normally by changing the combination of the reference oscillation frequency fxi of the reference oscillation signal and the multiplication number of the multiplication circuit without changing the local oscillation frequency fy. However, when the received signal is not demodulated normally in all combinations, the control unit 12 switches the first switching unit 23 to the second input state and switches the second switching unit 24 to the second output state. The PLL unit 22 may be selected.

  By the way, the wireless transceiver according to the present invention can be applied not only to the wireless communication system using the wireless communication device group described above but also to the wireless transmitter Y1 and the wireless receiver Y2 of the wireless remote control system. As this wireless transmitter Y1, in addition to having at least the transmission function of the above-described wireless transmitter / receiver of the present embodiment, an operation input presence / absence detection sensor, a pressure sensor, etc. It includes an object detection sensor YS that can be detected by a contact type using a passive detection sensor using heat, light, or vibration. The wireless receiver Y2 has at least the reception function of the wireless transmitter / receiver described above, and between the wireless transmitter Y1 and the equipment that is responsible for environmental adjustment of a specific location such as an air conditioner, lighting equipment, and equipment power supply. It also includes equipment control means YC that performs remote communication with a low risk of interference with the wireless communication. Signal transmission between the equipment control means YC and the equipment may be wired transmission or wireless transmission. As a result, the wireless transmitter that has detected that an object such as a human body or an obstacle is nearby is detected by the object detection sensor YS, and the wireless transmitter / receiver operates the wireless signal Sig3 indicating the event detected by the object detection sensor YS. The wireless receiver Y2 that is transmitted to the wireless receiver Y2 and receives the wireless signal Sig3 can receive the equipment control algorithm (equipment control algorithm YC provided in advance to the equipment control means YC only by turning on / off the equipment such as air conditioners and lighting equipment). And the operation operation mode of the equipment to be driven is determined from the equipment equipment group such as air conditioning equipment, lighting equipment and equipment power supply according to the contents of the received radio signal Sig3. The remote control of the equipment is executed according to the determination result. At this time, the radio receiver Y2 sends an answer-back signal Sig4 (which may be a so-called ACK signal) to the radio transmitter Y1 indicating that the radio signal Sig3 has been successfully received or has been interpreted. You may leave from. In this case, both the wireless transmitter Y1 and the wireless receiver Y2 need to have both a wireless transmission function and a wireless reception function. As described above, the wireless transmitter / receiver has different wireless frequencies for transmission and reception. In view of the high convenience in handling, it can be said that this form is desirable as a form to which the above-described wireless transceiver is applied.

DESCRIPTION OF SYMBOLS 1 Local oscillator 5 Mixer 9 Transmission part 11 Transmission / reception switching part 12 Control part (switching control part)
20 Reference oscillator 21 Multiplier (first frequency converter)
22 PLL section (second frequency conversion section)
23 1st switching part 24 2nd switching part

Claims (14)

A local oscillator that oscillates at a predetermined local oscillation frequency, a mixer that mixes the local oscillation signal of the local oscillation frequency output from the output terminal of the local oscillator and the radio signal received by the antenna, and modulates the local oscillation signal Then, a modulation circuit that generates a radio signal, a reception state in which the output terminal of the local oscillator is connected to the mixer, and a transmission state in which the output terminal is connected to the antenna without passing through the mixer are selected. A transmission / reception switching unit that automatically switches,
The local oscillator includes a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and a reference oscillation signal of the reference oscillation frequency output from an output terminal of the reference oscillation unit as the local oscillation signal. A first input state that converts the first and second frequency conversion units to be converted, and an output end of the reference oscillation unit to an input end of the first frequency conversion unit, and an output of the reference oscillation unit A first switching unit that selectively switches the input terminal to a second input state connected to the input terminal of the second frequency converter; and an output terminal of the local oscillator that outputs the first frequency converter. The first output state connected to the terminal and the second output state connecting the output terminal of the local oscillator to the output terminal of the second frequency converter are linked to the switching operation of the first switching unit. A second switching unit that switches alternatively.
The second frequency conversion unit includes a phase-locked loop circuit having a voltage controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency conversion unit is configured by the phase-locked loop circuit. Ri also Do not from the power consumption of less frequency multiplier circuit,
The local oscillator includes a bypass capacitor that AC-grounds a power supply terminal of the voltage controlled oscillator connected to an external power supply, an open / close unit that opens and closes a connection between the bypass capacitor and the external power supply or the power supply terminal, A current limiting resistor for limiting an inrush current flowing from the external power source to the bypass capacitor; and a short-circuit portion connected in parallel with the current limiting resistor, wherein the first switching portion is the second switching portion. The bypass capacitor and the external power supply or the power supply terminal are connected only when the input state is switched and the second switching unit is switched to the second output state. closing unit is shorted and said external power source and the power supply terminal after connecting the said bypass capacitor external power supply or the power supply terminal Radio transceiver characterized and. A local oscillator that oscillates at a predetermined local oscillation frequency, a mixer that mixes the local oscillation signal of the local oscillation frequency output from the output terminal of the local oscillator and the radio signal received by the antenna, and modulates the local oscillation signal Then, a modulation circuit that generates a radio signal, a reception state in which the output terminal of the local oscillator is connected to the mixer, and a transmission state in which the output terminal is connected to the antenna without passing through the mixer are selected. A transmission / reception switching unit that automatically switches,
The local oscillator includes a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and a reference oscillation signal of the reference oscillation frequency output from an output terminal of the reference oscillation unit as the local oscillation signal. A first input state that converts the first and second frequency conversion units to be converted, and an output end of the reference oscillation unit to an input end of the first frequency conversion unit, and an output of the reference oscillation unit A first switching unit that selectively switches the input terminal to a second input state connected to the input terminal of the second frequency converter; and an output terminal of the local oscillator that outputs the first frequency converter. The first output state connected to the terminal and the second output state connecting the output terminal of the local oscillator to the output terminal of the second frequency converter are linked to the switching operation of the first switching unit. A second switching unit that switches alternatively.
The second frequency conversion unit includes a phase-locked loop circuit having a voltage controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency conversion unit is configured by the phase-locked loop circuit. Consists of a frequency multiplier with low power consumption,
Further, the local oscillator selects and outputs a local oscillation signal having a reception local oscillation frequency different from the radio frequency of the radio signal and a local oscillation signal having a transmission local oscillation frequency equal to the radio frequency. The local oscillation signal having a relatively higher frequency selected from the local oscillation signal for reception and the local oscillation signal for transmission is converted and output to the first frequency conversion unit, radio transceiver you characterized by frequency converting the output of the local oscillator signal relatively lower in the second frequency converter. A local oscillator that oscillates at a predetermined local oscillation frequency, a mixer that mixes the local oscillation signal of the local oscillation frequency output from the output terminal of the local oscillator and the radio signal received by the antenna, and modulates the local oscillation signal Then, a modulation circuit that generates a radio signal, a reception state in which the output terminal of the local oscillator is connected to the mixer, and a transmission state in which the output terminal is connected to the antenna without passing through the mixer are selected. A transmission / reception switching unit that automatically switches,
The local oscillator includes a reference oscillation unit that oscillates at a predetermined reference oscillation frequency lower than the local oscillation frequency, and a reference oscillation signal of the reference oscillation frequency output from an output terminal of the reference oscillation unit as the local oscillation signal. A first input state that converts the first and second frequency conversion units to be converted, and an output end of the reference oscillation unit to an input end of the first frequency conversion unit, and an output of the reference oscillation unit A first switching unit that selectively switches the input terminal to a second input state connected to the input terminal of the second frequency converter; and an output terminal of the local oscillator that outputs the first frequency converter. The first output state connected to the terminal and the second output state connecting the output terminal of the local oscillator to the output terminal of the second frequency converter are linked to the switching operation of the first switching unit. A second switching unit that switches alternatively.
The second frequency conversion unit includes a phase-locked loop circuit having a voltage controlled oscillator, a phase comparator, a frequency divider, a loop filter, and a charge pump, and the first frequency conversion unit is configured by the phase-locked loop circuit. Consists of a frequency multiplier with low power consumption,
A switching control unit for controlling the first switching unit and the second switching unit, and the switching control unit is configured to switch the first switching unit when the transmission / reception switching unit is switched to a receivable state. Is switched to the first input state and the first switching is performed only when the received signal output from the mixer is not normally demodulated in the state in which the second switching unit is switched to the first output state. radio transceiver you characterized by switching the second switching unit to the second output state switches the part to said second input state. The reference oscillation unit, a radio transceiver according to any one of claims 1 to 3, characterized in that outputs alternatively switching said reference oscillation signal of a plurality of types of reference oscillation frequencies are different from each other. The local oscillator includes a bypass capacitor that AC-grounds a power supply terminal of the voltage controlled oscillator connected to an external power supply, and an open / close unit that opens and closes a connection between the bypass capacitor and the external power supply or the power supply terminal. The open / close unit is connected to the bypass capacitor only when the first switching unit is switched to the second input state and the second switching unit is switched to the second output state. 4. The wireless transceiver according to claim 2, wherein the external power supply or the power supply terminal is connected . The radio transceiver according to claim 5 , wherein the local oscillator includes a current limiting resistor that limits an inrush current flowing from the external power source to the bypass capacitor . The local oscillator includes a short-circuit unit connected in parallel with the current limiting resistor, and the short-circuit unit includes the external power source and the power source after the open / close unit connects the bypass capacitor and the external power source or the power source terminal. 7. The wireless transceiver according to claim 6, wherein the power terminal is short-circuited . The local oscillator selects and outputs a local oscillation signal having a reception local oscillation frequency different from the radio frequency of the radio signal and a local oscillation signal having a transmission local oscillation frequency equal to the radio frequency. Then, the local oscillation signal having a higher frequency selected from the local oscillation signal for reception and the local oscillation signal for transmission is converted and output to the first frequency conversion unit, and the frequency is radio transceiver of claim 1 or 3, wherein the converting outputs a local oscillation signal of a relatively lower in the second frequency converter. A switching control unit for controlling the first switching unit and the second switching unit, and the switching control unit is configured to switch the first switching unit when the transmission / reception switching unit is switched to a receivable state. Is switched to the first input state and the first switching is performed only when the received signal output from the mixer is not normally demodulated in the state in which the second switching unit is switched to the first output state. 3. The radio transceiver according to claim 1 , wherein the first switching unit is switched to the second input state and the second switching unit is switched to the second output state . 4. The switching control unit, after a predetermined time period has passed in the receivable state, claim 3, characterized in that to fix the state of the first and second switching unit to the state at the elapsed point of the predetermined period or 9. The wireless transceiver according to 9 . When the transmission / reception switching unit is switched to a receivable state, the local oscillator performs an intermittent operation that repeats an operation period and a pause period at a predetermined cycle, and the switching control unit performs the first operation at the start of the operation period. The radio according to any one of claims 3, 9, and 10, wherein one switching unit is switched to the first input state and the second switching unit is switched to the first output state. Transceiver. The switching control unit switches the first switching unit to the second input state and the number of times of switching the second switching unit to the second output state exceeds a predetermined number of times. 12. The wireless transceiver according to claim 11 , wherein the first switching unit is switched to the second input state and the second switching unit is switched to the second output state at the start of the operation . The reference oscillating unit selectively switches and outputs a plurality of types of the reference oscillation signals having different reference oscillation frequencies.
The first frequency converter has a plurality of multiplication circuits having different multiplication numbers from each other,
The switching control unit is configured so that a reception signal output from the mixer is normal when the first switching unit is switched to the first input state and the second switching unit is switched to the first output state. If the received signal is not demodulated normally in all combinations while sequentially changing the combination of the reference oscillation frequency of the reference oscillation signal and the multiplication number of the multiplication circuit without changing the local oscillation frequency The first switching unit is switched to the second input state, and the second switching unit is switched to the second output state. The radio transceiver described. The switching control unit includes a clock that measures time, and when the time counted by the clock is a daytime time zone, the first switching unit is switched to the second input state and the second input state is switched to the second input state. The switching unit is switched to the second output state, and when the time is a night time zone, the first switching unit is switched to the first input state and the second switching unit is switched to the first output state. The wireless transmitter / receiver according to claim 3, wherein the wireless transmitter / receiver is switched to the output state.

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