JP2007081708A - Wireless device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless device capable of reducing power consumption by controlling the current value of VCO, according to the C/N characteristics required by local signals. <P>SOLUTION: The wireless device comprises a LNA2 that amplifies reception signals supplied from an antenna, first VCO7, local amplifier 5 supplied by output of the first VCO, demodulator 3 that mixes the output of LNA with the local signal outputted from the local amplifier, GCA10 that amplifies the output signal of the demodulator, LPF4 that removes signals, corresponding to the interference waves from the output signal of GCA, a first detection circuit 11 for detecting output signal level of GCA, a second detection circuit 12 for detecting output signal level of LPF, a comparator 13 for comparing the detection output levels of first and second detection circuits with each other, and a control circuit for controlling the current value of VCO, according to the output of the comparator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radio apparatus capable of controlling a current of a VCO (voltage controlled oscillator) for supplying a local signal according to necessary C / N characteristics.

FIG. 7 shows the configuration of a conventional radio apparatus. A signal received by the antenna 1 is amplified by a LAN (low noise amplifier) 2 and then mixed with a local signal supplied via a local amplifier 5 by a mixer circuit 3 to be frequency-converted. The frequency-converted signal is amplified by a GCA (variable gain amplifier) 10 and then output as a baseband signal via the baseband LPF 4. The local signal is generated by a VCO (Voltage Controlled Oscillator) 7 and a PLL 6 and supplied to the mixer circuit 3 via the local amplifier 5. The current of the VCO 7 is controlled by the current control circuit 8 that has received the system mode switching signal 9. (For example, see Patent Document 1)
JP-A-10-79682

  In the configuration as in the above conventional example, when the system is switched, for example, GSM, UMTS, etc., the C / N characteristics of the local signal required in each system can be changed by changing the current. It is. However, even when the received signal level changes during reception and the C / N characteristic required for the local signal changes, a current that provides the highest C / N characteristic required within the received signal level continues to flow. There was a problem that it was necessary.

  An object of the present invention is to provide a wireless device that can reduce current consumption by controlling the current value of a VCO according to the C / N characteristic required for a local signal.

  In order to solve this problem, a radio apparatus according to a first configuration of the present invention includes an LNA (low noise amplifier) that amplifies a received signal supplied from an antenna, a first VCO (voltage controlled oscillator), and the first A first local amplifier to which the output of one VCO is supplied; a demodulator that demodulates the received signal based on an output of the LNA and a local signal output by the first local amplifier; and an output signal of the demodulator A first GCA (variable gain amplifier) to be amplified, an LPF (low pass filter) that removes a signal corresponding to an interference wave from the output signal of the first GCA, and an output signal level of the first GCA are detected. A first detection circuit that performs detection, a second detection circuit that detects an output signal level of the first LPF, a comparator that compares detection output levels of the first and second detection circuits, and the comparator Out of And a control circuit for controlling the current value of the first VCO in accordance with the.

  A radio apparatus having a second configuration according to the present invention includes an LNA that amplifies a reception signal supplied from an antenna, a first VCO, a first local amplifier to which an output of the first VCO is supplied, A demodulator that demodulates the received signal based on an output of the LNA and a local signal output from the first local amplifier, a first GCA that amplifies the output signal of the demodulator, and an output signal of the first GCA An LPF that removes a signal corresponding to an interference wave and a control circuit that controls the current value of the first VCO according to the level of the gain control signal of the receiving device are provided.

  According to the present invention, the C / N which requires the current value of the VCO based on the output of the received signal comparing the level of the desired wave signal and the interference wave signal or the level of the desired wave signal represented by the gain control signal. The current consumption of the wireless device can be reduced by optimal control according to the level.

  In the radio apparatus of the first configuration of the present invention, the LPF is configured by an attenuation variable LPF, and the control circuit controls the attenuation characteristic of the attenuation variable LPF according to the output of the comparator. be able to.

  In the radio apparatus according to the second configuration of the present invention, the LPF includes a plurality of cascaded LPFs, and includes an LPF changeover switch that selects and outputs one of the outputs of the plurality of LPFs. The circuit may be configured to control the LPF changeover switch and adjust the number of stages of the LPF according to the level of the gain control signal.

  The gain control signal may be an RSSI signal or a transmission power control signal from a base station in a W-CDMA radio system.

  In the radio apparatus according to the first or second configuration of the present invention, the control circuit controls the current value of the first local amplifier according to the output of the comparator or the level of the gain control signal. be able to.

  A second local amplifier to which the output of the first VCO is supplied; and a modulator that generates a transmission signal by mixing a baseband signal and a local signal output from the second local amplifier. Furthermore, it can be set as the structure provided.

  Further, the transmission signal is mixed by mixing the second VCO, the second local amplifier to which the output of the second VCO is supplied, the baseband signal and the local signal output from the second local amplifier. And a modulator that generates the control circuit, wherein the control circuit controls the current of the second VCO in accordance with the output of the comparator or the level of the gain control signal.

  The control circuit may be configured to control the current values of the first and second local amplifiers according to the output of the comparator or the level of the gain control signal.

  In addition, a frequency divider is provided to which the output of the first VCO is supplied, and the transmission frequency of the first VCO is N times the reception frequency, and is divided by 1 / N times by the frequency divider. A local signal is supplied to the local amplifier, and the control circuit controls the current of the frequency divider according to the output of the comparator or the level of the gain control signal.

  The control circuit controls at least one of the first and second VCOs, the first and second local amplifiers, and the first LPF for each transmission / reception slot in the TDMA radio system. It can be configured.

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

(Embodiment 1)
A radio apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of the receiving apparatus, and FIG. 2 shows the relationship between the received signal and the signal frequency spectrum after frequency conversion.

  The antenna 1 is connected to the LNA 2, and the received signal is amplified by the LNA 2 and input to the demodulator 3. The demodulator 3 demodulates the received signal by mixing the amplified received signal with the local signal supplied via the local amplifier 5. The output of the demodulator 3 is amplified by the GCA 10 and unnecessary signals are removed by the baseband LPF 4 to output a baseband signal.

  The output of the GCA 10 is detected by the detection circuit 11, and the baseband signal is detected by the detection circuit 12. The detection output of the detection circuit 11 and the detection output of the detection circuit 12 are compared by the comparator 13, and the output is input to the current control circuit 8. The output of the current control circuit 8 is supplied to the local amplifier 5 and the VCO 7 to control the current.

  Here, the frequency relationship of the received signal will be described with reference to FIG. A desired signal 108 and an interference wave 103 having a frequency f2 are input from the antenna 1. Frequency conversion is performed by the demodulator 3 to obtain a baseband signal 105 and an interference wave converted signal 109. The interference wave conversion signal 109 is removed by the baseband LPF 4.

  The frequency configurations of the baseband signal 105 and the interference wave conversion signal 109 are as follows. That is, the center frequency f0 part of the local signal 101 and the frequency f1 part 102 of the desired signal are mixed to obtain the frequency f1 part converted signal spectrum 106 of the frequency (f1-f0). Similarly, the interfering wave mixing noise 104 having the noise frequency f2 of the local signal 101 and the interfering wave 103 having the frequency f3 are mixed to obtain the frequency f3 converted signal spectrum 107 having the frequency (f3-f2).

  As described above, since the converted signal of the desired wave signal 108 and the interference wave signal 103 is mixed in the baseband signal 105, when the power level of the desired wave signal 108 becomes lower than the interference wave signal 103, the frequency f3 The influence of the converted signal spectrum 107 is increased, and accurate demodulation cannot be performed.

  When the power level of the desired wave signal 108 is high, or when the power level of the interfering wave signal 103 is low, the C / N characteristics of the local signal 101 may be relatively poor. On the other hand, when the power level of the desired wave signal 108 is low or when the power level of the interfering wave signal 103 is high, the C / N characteristic of the local signal 101 needs to be relatively improved.

  For example, assuming that the power levels of the frequencies f0, f1, f2, and f3 are 0 dBm, −80 dBm, −50 dBm, −30 dBm, and the gain by mixing is 0 dB, the frequency f1 converted signal spectrum 106 is −80 dBm, and the frequency f3 converted signal The spectrum 107 is −80 dBm. When the frequency level of the desired signal f1 is increased from -80 dBm to -50 dBm, if the gain by mixing is 0 dB, the frequency f1 converted signal spectrum 106 is -50 dBm, and the frequency f3 converted signal spectrum 107 is the same -50 dBm. The frequency f2 signal level is −20 dBm.

  The output obtained by detecting the output of the GCA 10 including the interference wave signal in the detection circuit 11 and the output obtained by detecting the baseband signal in the detection circuit 12 are compared in the comparator 13 and proportional to the difference voltage between the detection circuit 11 and the detection circuit 12. By outputting this voltage, a level ratio between the power level of the interference wave signal 103 and the power level of the desired wave signal 108 can be obtained.

  Based on the level ratio between the power level of the disturbing wave signal 103 and the power level of the desired wave signal 108, the current control circuit 8 converts the optimum C / N characteristic of the local signal and controls the current of the local amplifiers 5 and VCO7. As a result, the current can be reduced.

  According to the above configuration, even when the reception level changes and the necessary C / N characteristic of the local signal changes, a local signal with an optimum C / N characteristic can be obtained, and wireless power with reduced unnecessary current consumption can be obtained. You can get the device.

(Embodiment 2)
FIG. 3 shows the configuration of the radio apparatus according to Embodiment 2 of the present invention. The same elements as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description will not be repeated. The relationship between the received signal and the signal frequency spectrum after frequency conversion is as shown in FIG.

  In the present embodiment, unnecessary signals are removed from the output signals of the GCA 10 by the baseband LPFs 4, 21, 22 connected in cascade. Then, the baseband LPF changeover switch 23 outputs one of the baseband LPFs 4, 21, and 22 as a baseband signal. As a result, the filter characteristic of the required attenuation is selected and the baseband signal is adjusted. A reception gain control signal supplied by an element not shown is supplied to the control circuit 20, and the control circuit 20 controls the current of the local amplifier 5 and the VCO 7 and the baseband LPF changeover switch 23. Is called.

  Since the power level of the desired wave signal is obtained by the gain control signal, the control circuit 20 can convert the optimum C / N characteristic of the local signal according to the power level of the desired wave signal. Based on this, the current of the local amplifier 5 and VCO 7 is controlled to reduce the current. In addition, when the power level of the desired wave signal is high, the S / N characteristic is good, so that the attenuation of the filter can be reduced. Therefore, the baseband LPF switch 23 switches the paths of the baseband LPFs 4, 21, and 22 to reduce current.

  According to the above configuration, even when the reception level changes and the necessary C / N characteristic of the local signal changes, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained. it can. Even when the required attenuation characteristics of the baseband LPF change, unnecessary current consumption can be reduced by switching the path of the required baseband LPF.

  Although the signal input to the control circuit 20 is a gain control signal, an RSSI signal or a Tx output level control signal from a base station can be used in a W-CDMA system.

(Embodiment 3)
FIG. 4 shows the configuration of the radio apparatus according to Embodiment 3 of the present invention. The same elements as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description will not be repeated. The relationship between the received signal and the signal frequency spectrum after frequency conversion is as shown in FIG.

  In the present embodiment, the VCO 7 oscillates by multiplying the reception frequency, and a signal frequency-divided to the reception frequency by the frequency divider 25 is supplied to the local amplifier 5. The output signal of the GCA 10 is output as a baseband signal after unnecessary signals are removed by the attenuation variable baseband LPF 24. The output of the comparator 13 is input to the control circuit 25, and the control circuit 25 controls the current of the local amplifier 5, the frequency divider 25, the VCO 7, and the attenuation characteristics of the attenuation variable baseband LPF 24.

  Based on the result of comparing the power level of the interference wave signal 103 and the power level of the desired wave signal 108 (see FIG. 2) by the comparator 13, the control circuit 20 converts the optimum C / N characteristic of the local signal, and the local amplifier 5, the current is reduced by controlling the current of the frequency divider 25 and the VCO 7. Further, when the power level of the desired wave signal 108 is high, the S / N characteristic is good, so that the attenuation amount of the filter can be reduced, and the attenuation amount of the attenuation variable baseband LPF 24 is optimized to reduce the current.

  According to the above configuration, even when the reception level changes and the necessary C / N characteristic of the local signal changes, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained. it can. Further, even when the necessary attenuation characteristics of the baseband LPF change, it is possible to obtain a wireless device with reduced unnecessary current consumption by optimizing the necessary attenuation amount of the baseband LPF.

(Embodiment 4)
FIG. 5 shows the configuration of the radio apparatus according to Embodiment 4 of the present invention. The same elements as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description will not be repeated. The relationship between the received signal and the signal frequency spectrum after frequency conversion is as shown in FIG.

  In the present embodiment, the antenna 1 is connected to the antenna switch 14, the reception signal is sent from the antenna 1 to the LNA 2, and the transmission signal is sent from the variable amplifier 19 to the antenna 1. The transmission signal is generated by a baseband input inputted to the modulator 18 and a local signal injected from the VCO 7 via the local amplifier 15 and sent to a variable amplifier 19 composed of a PA and a driver amplifier. 14 to the antenna 1.

  The operation of the wireless communication apparatus having the above circuit configuration will be described below. For example, in a TDMA wireless system, a received signal received by the antenna 1 is sent to the LAN 2 by the antenna switch 14 and a baseband signal is output and a comparator as in the first embodiment shown in FIG. Based on the output of 13, the current control circuit 8 controls the current of the local amplifier 5 and the VCO 7. That is, based on the power level of the interference wave signal 103 and the power level of the desired wave signal 108, the current control circuit 8 converts the optimum C / N characteristic of the local signal and controls the current of the local amplifier 5 and the VCO 7. As a result, the current can be reduced.

  In order to obtain the necessary noise characteristics of the transmission signal, a high C / N characteristic is required for the local signal when the output level of the transmission signal is high, and the C / N characteristic may be low when the output level of the transmission signal is low. . Therefore, similarly to reception, the current control circuit 8 converts the optimum C / N characteristic of the local signal and controls the current of the local amplifier 15 and the VCO 7 to reduce the current.

  According to the above configuration, even when the reception level changes and the necessary C / N characteristic of the local signal changes, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained. it can. Further, even when the necessary transmission level changes and the C / N characteristics necessary for the local signal change, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained.

(Embodiment 5)
FIG. 6 shows the configuration of the radio apparatus according to the fifth embodiment of the present invention. Elements similar to those in the second embodiment shown in FIG. 3 and the fourth embodiment shown in FIG. 5 are denoted by the same reference numerals, and description thereof will not be repeated. The relationship between the received signal and the signal frequency spectrum after frequency conversion is as shown in FIG.

  In the present embodiment, the antenna 1 is connected to the duplexer 26, the received signal is sent from the antenna 1 to the LNA 2, and the transmission signal is sent from the variable amplifier 19 to the antenna 1. A local amplifier 15, a PLL 16 and a VCO 17 for supplying a local signal used for generating a transmission signal are provided separately from the reception side.

  A gain control signal is input to the control circuit 20, and the control circuit 20 controls the currents of the reception-side local amplifiers 5 and VCO 7 and the transmission-side local amplifier 15 and VCO 17.

  Since the power level of the desired wave signal 108 can be obtained by the gain control signal, the control circuit 20 converts the optimum C / N characteristic of the local signal and controls the current of the local amplifier 5 and the VCO 7 to reduce the current. It is done.

  Further, in order to obtain the necessary noise characteristics of the transmission signal, a high C / N characteristic is required as a local signal when the output level of the transmission signal is high, and the C / N characteristic is low when the output level of the transmission signal is low. Also good.

  A high gain required in the receiving device means a high output level required in the transmitting device. Therefore, since the necessary transmission output level can be obtained by the gain control signal, the control circuit 20 converts the optimum C / N characteristic of the local signal and controls the current of the local amplifier 15 and the VCO 17 to reduce the current. Figured.

  According to the above configuration, even when the reception level changes and the necessary C / N characteristic of the local signal changes, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained. it can. Further, even when the necessary transmission level changes and the C / N characteristics necessary for the local signal change, an optimal C / N can be obtained, and a wireless device with reduced unnecessary current consumption can be obtained.

  Although the signal input to the control circuit 20 is a gain control signal, an RSSI signal or a Tx output level control signal from a base station can be used in a W-CDMA system.

  The radio apparatus of the present invention can optimally control the current value of the VCO according to the transmission / reception level, and is effective in reducing the current of the local circuit and the baseband LPF.

1 is a block diagram showing a radio apparatus according to Embodiment 1 of the present invention. Frequency spectrum diagram showing relationship between received signal and signal frequency spectrum after frequency conversion in each embodiment of the present invention FIG. 2 is a block diagram showing a radio apparatus according to Embodiment 2 of the present invention. FIG. 9 is a block diagram showing a radio apparatus according to Embodiment 3 of the present invention. FIG. 9 is a block diagram showing a radio apparatus according to the fourth embodiment of the present invention. FIG. 9 is a block diagram showing a radio apparatus according to the fifth embodiment of the present invention. Block diagram showing a conventional radio apparatus

Explanation of symbols

1 Antenna 2 LNA
3 Demodulator 4, 21, 22 Baseband LPF
5,15 Local amplifier 6,16 PLL
7,17 VCO
8 Current control circuit 9 System mode switching signal 10 GCA
DESCRIPTION OF SYMBOLS 11, 12 Detection circuit 13 Comparator 14 Antenna switch 18 Modulator 19 Variable amplifier 20 Control circuit 23 Baseband LPF changeover switch 24 Attenuation variable baseband LPF
25 Frequency divider 26 Duplexer 101 Local signal 102 Frequency f1 part 103 Interference wave 104 Interference wave mixing noise 105 Baseband signal 106 Frequency f1 part conversion signal spectrum 107 Frequency f3 conversion signal spectrum 108 Desired signal 109 Interference wave conversion signal

Claims (11)

LNA (low noise amplifier) that amplifies the received signal supplied from the antenna;
A first VCO (voltage controlled oscillator);
A first local amplifier to which the output of the first VCO is supplied;
A demodulator that demodulates the received signal by mixing the output of the LNA and the local signal output by the first local amplifier;
A first GCA (variable gain amplifier) for amplifying the output signal of the demodulator;
An LPF (low pass filter) for removing a signal corresponding to an interference wave from the output signal of the first GCA;
A first detection circuit for detecting an output signal level of the first GCA;
A second detection circuit for detecting an output signal level of the first LPF;
A comparator for comparing detection output levels of the first and second detection circuits;
And a control circuit that controls a current value of the first VCO according to an output of the comparator.   The radio apparatus according to claim 1, wherein the LPF is configured by an attenuation variable LPF, and the control circuit controls an attenuation characteristic of the attenuation variable LPF according to an output of the comparator. An LNA for amplifying a received signal supplied from an antenna;
A first VCO;
A first local amplifier to which the output of the first VCO is supplied;
A demodulator that demodulates the received signal by mixing the output of the LNA and the local signal output by the first local amplifier;
A first GCA for amplifying the output signal of the demodulator;
An LPF for removing a signal corresponding to an interference wave from the output signal of the first GCA;
A radio apparatus comprising: a control circuit that controls a current value of the first VCO according to a level of a gain control signal of the receiving apparatus. The LPF is composed of a plurality of cascaded LPFs,
An LPF changeover switch that selects and outputs one of the outputs of the plurality of LPFs;
The radio apparatus according to claim 3, wherein the control circuit adjusts the number of stages of the LPF by controlling the LPF changeover switch according to a level of the gain control signal.   The radio apparatus according to claim 3 or 4, wherein the gain control signal is an RSSI signal or a transmission power control signal from a base station in a W-CDMA radio system.   The radio apparatus according to claim 1, wherein the control circuit controls a current value of the first local amplifier according to an output of the comparator or a level of the gain control signal. A second local amplifier to which the output of the first VCO is supplied;
The radio apparatus according to claim 1, further comprising a modulator that generates a transmission signal based on a baseband signal and a local signal output from the second local amplifier. A second VCO;
A second local amplifier to which the output of the second VCO is supplied;
A modulator that generates a transmission signal based on a baseband signal and a local signal output from the second local amplifier;
The radio apparatus according to claim 1, wherein the control circuit controls a current of the second VCO according to an output of the comparator or a level of the gain control signal.   The radio apparatus according to claim 7 or 8, wherein the control circuit controls a current value of the first and second local amplifiers according to an output of the comparator or a level of the gain control signal. A frequency divider to which the output of the first VCO is supplied;
The transmission frequency of the first VCO is N times the reception frequency;
A signal divided by 1 / N times by the frequency divider is supplied to the local amplifier as a local signal,
The radio apparatus according to claim 1, wherein the control circuit controls a current of the frequency divider according to an output of the comparator or a level of the gain control signal.   The control circuit performs control on at least one of the first and second VCOs, the first and second local amplifiers, and the first LPF for each transmission / reception slot in a TDMA radio system. The wireless device according to any one of 1 to 10.

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