JP2007312178A - Receiver and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver and a receiving method capable of obtaining sufficient characteristics with respect to the reduction of power consumption while appropriately suppressing an image signal. <P>SOLUTION: A received signal is frequency-converted into an intermediate frequency signal in a frequency conversion circuit 130, the image signal included in the intermediate frequency signal is rejected by an image rejection circuit 150, however, operation modes are switched by partially stopping a circuit in the image rejection circuit 150, etc. according to a level of the image signal detected by an image signal level detection circuit 160 and power consumption equivalent to this stop is saved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a receiving apparatus and a receiving method for performing signal processing including frequency conversion processing for generating an intermediate frequency signal by down-converting a received signal of a carrier wave, and in particular, receiving that exhibits excellent characteristics with respect to power consumption suppression. The present invention relates to an apparatus and a receiving method.

For example, in a communication apparatus including a frequency conversion processing function unit such as a superheterodyne reception apparatus, there is always a general request for reducing power consumption. There is something strong. Conventionally, proposals have been made to reduce power consumption in response to the above-described requirements in a receiving apparatus to which an image rejection mixer is applied as a mixer that forms the core of the frequency conversion processing function unit.

For example, there is a proposal to reduce power consumption by applying a grid circuit including an inductor and a resistor instead of a circuit using a known CR grid. In this proposal, a local signal distributed to two systems having a phase difference is input to an image rejection mixer, and the 2
By mixing the local signal of the system and each high-frequency signal having a phase difference, two systems of intermediate frequency current signals having a phase difference of 90 degrees are obtained, and this phase difference is converted into a grid of inductors and resistors. It is generated by applying phase shift means that is a circuit, and both intermediate frequency current signals having the phase difference are added by an adding means to obtain an output in which an image is suppressed (see, for example, Patent Document 1).
JP 2001-284968 A

However, in the technique as proposed in Patent Document 1, in order to handle two systems of signals having a phase difference of 90 degrees, both signal processing systems related to these two systems are always operating, From the viewpoint of power suppression, sufficient characteristics are not necessarily obtained.
The present invention has been made in view of the situation described above, and provides a receiving apparatus and a receiving method capable of obtaining sufficient characteristics for reducing power consumption while appropriately suppressing image signals. It is intended to provide.

In order to solve the above-described problems, the present application proposes the following techniques.
(1) A reception apparatus including a frequency conversion circuit that converts a received signal into a signal having a frequency lower than that of the received signal, and removes an image signal included in the signal that has been frequency converted by the frequency conversion circuit. And an image signal level detection circuit for detecting the level of the image signal, and the image removal circuit is configured to operate in an operation mode corresponding to the detection output of the image signal level detection circuit. A receiving apparatus.

In the receiver of (1) above, the received signal is frequency-converted to a signal having a frequency lower than that of the received signal by the frequency converting circuit, and the image signal included in this signal is removed by the image removing circuit. Depending on the level of the image signal detected by the detection circuit, the operation mode of image signal removal in the image removal circuit is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

(2) The image removal circuit has two systems set so that the signal phases are orthogonal between one system and the other system, and a complex filter corresponding to the two systems is provided. And an image signal is removed by the complex filter.
In the receiver of (2) above, the signal processing system having two systems in which the phase of the signal is set to be orthogonal between one system and the other system, particularly with respect to the operation of the receiver of (1). After that, the image signal is removed.

(3) The image removal circuit has two systems, and a phase shifter is inserted in one of the two systems, and is inserted into a system in which the phase shifter is inserted. The receiver according to (1), which is configured to remove the image signal by adding the outputs from the non-system.
In the receiver of the above (3), regarding the operation of the receiver of (1), in particular, signal processing by two systems in which a phase shifter is inserted is performed, and the phase shifter is inserted. The image signals are removed by adding the outputs of the existing system and the non-interpolated system.

(4) The receiving apparatus according to (3), wherein the two systems of the image removal circuit include a band-pass filter of a predetermined frequency inserted in each system.
In the receiver of the above (4), regarding the operation of the receiver of (3), in particular, the signals of the two systems of the image removal circuit are filtered by the band filters of the predetermined frequency of each system, and the band well suited to the specifications. It is attached to processing as a signal.

(5) At least one of the systems is provided with two carrier signal transmission systems in which phase shifters are inserted so as to guide the received signal to the frequency conversion circuit, and the image removal circuit includes the two carriers. (2) The receiving apparatus according to (1), comprising two systems corresponding to the signal transmission system, and configured to remove the image signal by adding the outputs of the two systems.
In the receiving device of (5) above, with respect to the operation of the receiving device of (1), in particular, the received signal is transferred to the frequency conversion circuit by two carrier signal transmission systems in which one of the systems is inserted with a phase shifter. Then, the outputs of the two systems are added through a signal processing system having two systems corresponding to these two carrier signal transmission systems, and the image signal is removed.

(6) The receiving apparatus according to (5), wherein a band filter of a predetermined frequency is inserted in each of the two systems of the image removal circuit.
In the receiver of the above (6), regarding the operation of the receiver of (5), in particular, the signals of the two systems of the image removal circuit are filtered by the band filters of the predetermined frequencies of the respective systems, and the band that is well adapted to the specifications. It is attached to processing as a signal.

(7) The image removal circuit is configured to switch the operation mode so as to cut off the supply of the operation power to one of the two systems according to the detection output of the image signal level detection circuit. The receiving apparatus according to any one of (2) to (6), wherein:
In the receiving device according to (7) above, with respect to the operation of the receiving device according to any one of (2) to (6), in particular, the detection output of the image signal level detection circuit, for example, the level of the image signal is a predetermined value. When the value is lower, the operation mode is switched so as to partially cut off the supply of the operation power to the image removal circuit, so that power consumption can be reduced in accordance with the stoppage of power supply.

(8) The image removal circuit cuts off the supply of operating power to one of the two systems in accordance with the detection output of the image signal level detection circuit and removes the one system from the other system. The receiving apparatus according to any one of (2) to (6), wherein the operation mode is switched so as to be insulated.
In the receiver of (8) above, with respect to the operation of the receiver according to any one of (2) to (6), in particular, a value indicating that the detection output of the image signal level detection circuit is below a predetermined value. In some cases, the operation mode is switched so as to partially cut off the supply of the operating power to the image removal circuit, so that the power consumption can be reduced in accordance with the stoppage of the power supply. Since the disconnected circuit portion is insulated from the active circuit portion, there is no possibility of unnecessary interference with respect to signal processing.

(9) A reception method for performing signal processing including processing for frequency conversion of a received signal into an intermediate frequency signal having a frequency lower than that of the received signal, and an image removal circuit for removing an image signal included in the intermediate frequency signal The receiving method is characterized in that the operation mode is changed according to the detection output of the level of the image signal.
In the reception method of (9) above, if the operation mode is changed such as partially stopping the operation of the image removal circuit when the level of the image signal falls below a predetermined value, the power consumption corresponding to the stop can be reduced. Figured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings to be referred to below, for the sake of convenience, the main part that is the subject of the description is exaggerated as appropriate, and other than the main part is appropriately simplified or omitted.

FIG. 1 is a block diagram showing a configuration of a receiving apparatus according to the first embodiment of the present invention.
In FIG. 1, a received signal supplied as a carrier signal received by an antenna (not shown) or a carrier signal distributed by wire is branched into two systems, a first system 111 and a second system 112. Are input to the mixer unit 110.
The mixer unit 110 is provided with a first mixing circuit 113 corresponding to the first system 111 and a second mixing circuit 114 corresponding to the second system. The mixing circuits 113 and 114 include a local oscillator 120. Is supplied with a local oscillation signal.

That is, one output signal system 121 emitted from the local oscillator 120 is directly supplied to the first mixing circuit 113, and the other output signal system 122 is passed through the 90 ° phase shifter 123.
This is supplied to the second mixing circuit 114. As a result, in the first mixing circuit 113 and the second mixing circuit 114, the received signals of the first system 111 and the second system 112 are respectively converted into intermediate frequency signals having lower frequencies.

That is, the mixer unit 110 and the local oscillator 120 constitute a frequency conversion circuit 130 that converts the received signal into an intermediate frequency signal having a frequency lower than that of the received signal. The output of the frequency conversion circuit 130 (mixer unit 110) passes through the intermediate frequency complex filter 140 that functions to remove the image signal included in the intermediate frequency signal and functions as a bandpass filter, and the first system 141 and the second system The signals are output as two signals of the system 142.
As described above, the input signal is handled in the form of being divided into two systems. In one example, the system from the input signal of the first system 111 to the output signal of the first system 141 is an I signal system. The system from the input signal of the second system 112 to the output signal of the second system 142 is a system of Q signals.

In this embodiment, as described above, the intermediate frequency signal processing system has two systems set so that the signal phases are orthogonal between one system and the other system, and An intermediate frequency complex filter 140 corresponding to two systems is provided, and an image signal is removed by the complex filter. Accordingly, the intermediate frequency complex filter 140 and the mixer unit 130 as an image removal function unit are provided. It can be seen that the image signal removal circuit 150 is configured as shown by being surrounded by a one-dot chain line.

In the embodiment of FIG. 1, a detection point P1 for detecting the level of the image signal is set in the second system 142 of the output signal, and the image signal level detection for detecting the level of the image signal from the detection point P1. A circuit 160 is provided. The image signal removal circuit 150
The image signal included in the intermediate frequency signal is removed in an operation mode corresponding to the detection output of the image signal level detection circuit 160. Processing for detecting the level of the image signal, switching of the operation mode of the image signal removal circuit 150, and the like will be described in more detail later with reference to the drawings.
In the above example, the detection point P1 for detecting the level of the image signal is set to the second system 142 of the output signal. Instead, the detection point P1 is set to the first system 141 of the output signal.
May be set, and these can be appropriately selected according to the circumstances at the time of design.

In the first embodiment of FIG. 1, the received signal is frequency converted into an intermediate frequency signal by the frequency conversion circuit 130, and the image signal included in the intermediate frequency signal is converted into an image removal circuit 150.
However, depending on the level of the image signal detected by the image signal level detection circuit 160, the operation mode of image signal removal in the image removal circuit 150 is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

FIG. 2 is a block diagram showing a configuration of a receiving apparatus according to the second embodiment of the present invention.
In FIG. 2, a received signal supplied as a carrier signal received by an antenna (not shown) or a carrier signal distributed by wire is branched into two systems, a first system 211 and a second system 212. Are input to the mixer unit 210.
The mixer unit 210 is provided with a first mixing circuit 213 corresponding to the first system 211 and a second mixing circuit 214 corresponding to the second system 212, and these mixing circuits 213 and 2 are provided.
14 is supplied with a local oscillation signal emitted from the local oscillator 220.

In the second embodiment shown in FIG. 2, one output signal system 221 emitted from the local oscillator 220 is directly supplied to the first mixing circuit 213, and the other output signal system 222 is 90 °. It is supplied to the second mixing circuit 214 via the phase shifter 223. As a result, in the first mixing circuit 213 and the second mixing circuit 214, the received signals of the first system 211 and the second system 212 are frequency-converted into intermediate frequency signals having lower frequencies, respectively.

That is, the mixer unit 210 and the local oscillator 220 constitute a frequency conversion circuit 230 that converts the received signal into an intermediate frequency signal having a frequency lower than that of the received signal. The two output signals of the frequency conversion circuit 230, that is, the output signals of the first output signal system 231 and the second output signal system 232 are supplied to the addition circuit 240 and added, and the output signal from which the image has been removed. Is configured to get.

In the embodiment of FIG. 2, the first output signal system 231 emitted from the first mixing circuit 213 of the frequency conversion circuit 230 (its mixer section 210) is directly supplied to one input terminal of the adder circuit 240. On the other hand, the second output signal system 232 emitted from the second mixing circuit 214
Is supplied to the other input terminal of the adder circuit 240 via the 90 ° phase shifter 233. As a result, an output signal from which the image signal has been removed is obtained in the output signal system 241 of the adder circuit 240.

In the second embodiment, the intermediate frequency signal processing system has two systems, and the 2
A phase shifter (90 ° phase shifter 2) is connected to any one of the two systems (second output signal system 232 in the illustrated example).
33) is inserted, and the outputs of the system in which the phase shifter is inserted and the system in which the phase shifter is not inserted are added by the adder circuit 240, and the image signal is removed, so that the image signal is removed. It can be seen that the image signal removal circuit 250 as shown in FIG.

In the embodiment of FIG. 2, the output signal system 241 is provided with a detection point P2 for detecting the level of the image signal, and an image signal level detection circuit 260 for detecting the level of the image signal from the detection point P2 is provided. It has been. The above-described image removal circuit 250 removes the image signal included in the intermediate frequency signal in an operation mode corresponding to the detection output of the image signal level detection circuit 260. A phenomenological description of the processing for detecting the level of the image signal will be given later with reference to the drawings common to the other embodiments.

In the second embodiment of FIG. 2, the received signal is frequency converted into an intermediate frequency signal by the frequency conversion circuit 230, and the image signal included in the intermediate frequency signal is converted into the image removal circuit 250.
However, depending on the level of the image signal detected by the image signal level detection circuit 260, the operation mode of the image signal removal in the image removal circuit 250 is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

FIG. 3 is a block diagram showing a configuration of a receiving apparatus according to the third embodiment of the present invention.
In FIG. 3, a received signal supplied as a carrier signal received by an antenna (not shown) or as a carrier signal distributed by wire is branched into two systems, a first system 311 and a second system 312. Are input to the mixer unit 310.
The mixer unit 310 is provided with a first mixing circuit 313 corresponding to the first system 311 and a second mixing circuit 314 corresponding to the second system 312, and these mixing circuits 313 and 3 are provided.
14 is supplied with a local oscillation signal emitted from the local oscillator 320.

In the third embodiment shown in FIG. 3, one output signal system 321 emitted from the local oscillator 320 is directly supplied to the first mixing circuit 313, and the other output signal system 322 is 90 °. It is supplied to the second mixing circuit 314 via the phase shifter 323. As a result, in the first mixing circuit 313 and the second mixing circuit 314, the received signals of the first system 311 and the second system 312 are frequency-converted into intermediate frequency signals having lower frequencies, respectively.

That is, the mixer unit 310 and the local oscillator 320 constitute a frequency conversion circuit 330 that converts the received signal into an intermediate frequency signal having a frequency lower than that of the received signal. The two output signals of the frequency conversion circuit 330, that is, the output signals of the first output signal system 331 and the second output signal system 332 are supplied to the addition circuit 340 and added, and the output signal from which the image has been removed. Is configured to get.

In the embodiment of FIG. 3, the first output signal system 331 emitted from the first mixing circuit 313 of the frequency conversion circuit 330 (its mixer unit 310) has a first intermediate frequency filter (in the drawing,
(Noted as IF filter) 333 and supplied to one input terminal of the adding circuit 340,
A second output signal system 332 emitted from the second mixing circuit 314 passes through a second intermediate frequency filter (denoted as IF filter in the figure) 334, and further via a 90 ° phase shifter 336. 340 is supplied to the other input terminal. As a result, the output signal system 3 of the adder circuit 340
In 41, an output signal from which the image signal has been removed is obtained. In this embodiment, in particular, the first
The output signal system 331 includes a first intermediate frequency filter 333 and a second output signal system 332.
Since the second intermediate frequency filter 334 is inserted in each, only the desired signal can be obtained.

In the third embodiment, the intermediate frequency signal processing system has two systems, and the 2
Two systems (in the example shown, the first output signal system 331 and the second output signal system 332)
In addition, an intermediate frequency filter (in the illustrated example, the first intermediate frequency filter 333 and the second intermediate frequency filter 334) are inserted, and any one of the systems (in the illustrated example, the second output signal system). 332) is provided with a phase shifter (90 ° phase shifter 336), and the output of the system in which the phase shifter is inserted and the system in which the phase shifter is not inserted is added by an adder circuit 340. It can be seen that the image signal removal circuit 350 as shown by the one-dot chain line is configured to remove the signal.

In the embodiment of FIG. 3, a detection point P3 for detecting the level of the image signal is set in the output signal system 341, and an image signal level detection circuit 360 for detecting the level of the image signal from the detection point P3 is provided. It has been. The image removal circuit 350 described above removes the image signal included in the intermediate frequency signal in an operation mode corresponding to the detection output of the image signal level detection circuit 360. A phenomenological description of the processing for detecting the level of the image signal will be given later with reference to the drawings common to the other embodiments.

In the third embodiment of FIG. 3, the received signal is frequency converted into an intermediate frequency signal by the frequency conversion circuit 330, and the image signal included in the intermediate frequency signal is converted into an image removal circuit 350.
However, depending on the level of the image signal detected by the image signal level detection circuit 360, the operation mode of image signal removal in the image removal circuit 350 is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

FIG. 4 is a block diagram showing a configuration of a receiving apparatus according to the fourth embodiment of the present invention.
In FIG. 4, a received signal supplied as a carrier signal received by an antenna (not shown) or a carrier signal distributed by wire is branched into two systems, a first system 411 and a second system 412. The first system 411 is directly connected, and the second system 412 is a 90 ° phase shifter 416.
Are input to the mixer section 410 via the.
The mixer unit 410 is provided with a first mixing circuit 413 corresponding to the first system 411 and a second mixing circuit 414 corresponding to the second system 412, and these mixing circuits 413 and 4 are provided.
14 is supplied with a local oscillation signal emitted from the local oscillator 420.

In the fourth embodiment shown in FIG. 4, one output signal system 421 emitted from the local oscillator 420 is directly supplied to the first mixing circuit 413, and the other output signal system 422 is 90 °. It is supplied to the second mixing circuit 414 via the phase shifter 423. As a result, in the first mixing circuit 413 and the second mixing circuit 414, the received signals of the first system 411 and the second system 412 are frequency-converted into intermediate frequency signals having lower frequencies, respectively.

That is, the mixer unit 410 and the local oscillator 420 constitute a frequency conversion circuit 430 that converts the frequency of the received signal into an intermediate frequency signal having a frequency lower than that of the received signal. The two output signals of the frequency conversion circuit 430, that is, the output signals of the first output signal system 431 and the second output signal system 432, are supplied to the addition circuit 440 and added, and the output signal from which the image is removed Is configured to get.

In the fourth embodiment, a carrier signal transmission path that guides a received signal to the frequency conversion circuit 430 is provided with a phase shifter (at least one of the second systems 412 in the illustrated embodiment).
In the illustrated embodiment, it is configured as having two carrier signal transmission systems in which a 90 ° phase shifter 416) is inserted, and the outputs of the two systems are added by an adder circuit 440. An image signal removal circuit 450 as shown by the alternate long and short dash line so as to remove the signal.
Can be seen as being composed.

In the embodiment of FIG. 4, a detection point P4 for detecting the level of the image signal is set in the output signal system 441, and an image signal level detection circuit 460 for detecting the level of the image signal from the detection point P4 is provided. It has been. The image removal circuit 450 described above removes the image signal included in the intermediate frequency signal in an operation mode corresponding to the detection output of the image signal level detection circuit 460. A phenomenological description of the processing for detecting the level of the image signal will be given later with reference to the drawings common to the other embodiments.

In the fourth embodiment shown in FIG. 4, the received signal is frequency converted into an intermediate frequency signal by the frequency conversion circuit 430, and the image signal included in the intermediate frequency signal is converted into an image removal circuit 450.
However, depending on the level of the image signal detected by the image signal level detection circuit 460, the operation mode of image signal removal in the image removal circuit 450 is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

FIG. 5 is a block diagram showing a configuration of a receiving apparatus according to the fifth embodiment of the present invention.
In FIG. 5, a received signal supplied as a carrier signal received by an antenna (not shown) or a carrier signal distributed by wire is branched into two systems, a first system 511 and a second system 512. The first system 511 is directly connected, and the second system 512 is a 90 ° phase shifter 516.
Are input to the mixer unit 510.
The mixer unit 510 is provided with a first mixing circuit 513 corresponding to the first system 511 and a second mixing circuit 514 corresponding to the second system 512, and these mixing circuits 513 and 5 are provided.
14 is supplied with a local oscillation signal generated from the local oscillator 520.

In the fifth embodiment shown in FIG. 5, one output signal system 521 emitted from the local oscillator 520 is directly supplied to the first mixing circuit 513, and the other output signal system 522 is 90 °. It is supplied to the second mixing circuit 514 via the phase shifter 523. As a result, in the first mixing circuit 513 and the second mixing circuit 514, the received signals of the first system 511 and the second system 512 are frequency-converted into intermediate frequency signals having lower frequencies, respectively.

That is, the mixer unit 510 and the local oscillator 520 constitute a frequency conversion circuit 530 that converts the frequency of the received signal into an intermediate frequency signal having a frequency lower than that of the received signal. The two output signals of the frequency conversion circuit 530, that is, the output signals of the first output signal system 531 and the second output signal system 532, are respectively supplied to the addition circuit 540 and added to remove the image. Configured to obtain an output signal.

In the embodiment of FIG. 5, the first output signal system 531 emitted from the first mixing circuit 513 of the frequency conversion circuit 530 (its mixer unit 510) has a first intermediate frequency filter (in the drawing,
(Noted as IF filter) 533 and supplied to one input terminal of the adder circuit 540,
The second output signal system 532 emitted from the second mixing circuit 514 is supplied to the other input terminal of the adder circuit 540 through a second intermediate frequency filter (denoted as IF filter in the figure) 534.

As a result, an output signal from which the image signal has been removed is obtained in the output signal system 541 of the adder circuit 540. Particularly in this embodiment, the first output signal system 531 is provided with a first intermediate frequency filter 533 and the second output signal system 532 is provided with a second intermediate frequency filter 534. Only the desired signal can be obtained. In the fifth embodiment, at least one of the carrier signal transmission paths that guide the received signal to the frequency conversion circuit 530 (the second system 512 in the illustrated embodiment) has a phase shifter (not illustrated). In this embodiment, the 90 ° phase shifter 51
6) is configured to have two carrier signal transmission systems interpolated, and each output of the two systems is added by an adder circuit 540 and is surrounded by an alternate long and short dash line. It can be seen that the image signal removal circuit 550 as shown in FIG.

In the embodiment of FIG. 5, a detection point P5 for detecting the level of the image signal is set in the output signal system 541, and an image signal level detection circuit 560 for detecting the level of the image signal from the detection point P5 is provided. It has been. The image removal circuit 550 described above removes the image signal included in the intermediate frequency signal in an operation mode corresponding to the detection output of the image signal level detection circuit 560. A phenomenological description of the processing for detecting the level of the image signal will be given later with reference to the drawings common to the other embodiments.

In the fifth embodiment of FIG. 5, the received signal is frequency-converted to an intermediate frequency signal by the frequency conversion circuit 530, and the image signal included in the intermediate frequency signal is converted to the image removal circuit 550.
However, depending on the level of the image signal detected by the image signal level detection circuit 560, the operation mode of image signal removal in the image removal circuit 550 is switched. If the operation mode is switched such as partially stopping the operation of the image removal circuit when the level of the image signal is lower than the predetermined value, the power consumption corresponding to the stop can be reduced.

FIG. 6 is a block diagram illustrating a configuration example of an image signal level detection circuit applied to the first to fifth embodiments of FIGS. 1 to 5.
In FIG. 6, the detection points P1 to P5 in the first to fifth embodiments are typically shown as Pn. The signal input from the detection point Pn of the image signal included in the intermediate frequency signal is first converted into a DC voltage having a fixed relationship with the image signal that is the detected signal by the integration circuit 601, and the voltage comparison circuit in the next stage. Reference voltage source 6 at 602
Compared with the reference voltage value supplied from 03, for example, a binary signal that becomes 1 when the DC voltage value output from the integrating circuit 601 is equal to or higher than the reference voltage value, and becomes 0 when the DC voltage value is less than the reference voltage value. Converted. Based on the output of the image signal level detection circuit in the form of a binary signal, control for power saving as described later with reference to the drawings is executed.

FIG. 7 is a diagram for explaining the phenomenon related to the process of extracting the image signal for detecting the level of the image signal in the first embodiment of FIG.
The (a) part of FIG. 7 represents the effect | action of the normal image suppression by the intermediate frequency complex filter 140 of FIG. In normal image suppression, it functions as a band filter (denoted as IF Filter in the figure) of an intermediate frequency to be a desired signal, and a desired intermediate frequency signal (
The desired IF signal in the figure is extracted.

On the other hand, part (b) of FIG. 7 represents a case where the intermediate frequency complex filter 140 is made to function for image signal extraction. In the extraction of the image signal, it functions as an intermediate frequency band filter corresponding to the image signal (indicated as IF Filter in the figure), and extracts the intermediate frequency image signal (indicated in the lower part of the figure) to be extracted. To do.
As described above, an example of the circuit operation for switching the function of the intermediate frequency complex filter will be described later with reference to FIGS.

FIG. 8 is a diagram for explaining the phenomenon related to the process of extracting the image signal for detecting the level of the image signal in the first to fifth embodiments of FIGS. 1 to 5.
Normally, when an intermediate frequency band filter (indicated by IF Filter in the figure) is used for extracting a desired signal, the input carrier signal (RF in the figure) is related to the relationship shown in the upper left and middle left of the figure. Signal) and the local oscillator signal (designated LO in the figure) are located on the frequency axis, and as shown in the upper right frame of the figure, an intermediate frequency bandpass filter (designated in the figure) The desired intermediate frequency signal (denoted as a desired IF signal in the figure) is extracted with IF Filter.

On the other hand, when extracting the image signal, the frequency of the input carrier signal (denoted as RF signal in the figure) and the local oscillator signal (denoted as LO in the figure) is related to the frequency shown in the lower left part of the figure. The signal frequency of the local oscillator is changed so that the relationship is located on the axis. Then, as shown in the lower right frame of the figure, an intermediate frequency signal of the image (denoted as an image signal in the figure) is extracted by an intermediate frequency bandpass filter (denoted as IF filter in the figure).
The change of the signal frequency of the local oscillator as described above is performed in each of the local oscillators 120, 220, 320, 420, and 52 in the first embodiment of FIG. 1 to the fifth embodiment of FIG.
This corresponds to changing the oscillation frequency of zero.

FIG. 9 is a circuit diagram illustrating a configuration example of the mixer unit 110 in the embodiment of FIG. still,
In FIG. 9, for the sake of convenience of explanation, the first system 1 from the input signal of the first system 111 in FIG.
The system reaching the output signal 41 is an I signal system, and the second input signal from the second system 112 is the second one.
It is assumed that the system reaching the output signal of the system 142 is a system of Q signals.
In the figure, the circuit portion occupying the left half is a mixer circuit relating to the I signal system, and resistors R11, R
12, transistors Tr11, Tr12, Tr13, Tr14, Tr15, Tr16, Tr17, and
The connection is configured as shown, including the constant current source 91 and the like.

In the figure, the circuit portion occupying the right half is a mixer circuit related to the Q signal system, and the resistance R
21 and R22, transistors Tr21, Tr22, Tr23, Tr24, Tr25, Tr26, Tr27, and a constant current source 92, etc., are connected as shown in the figure. In particular, this mixer is powered from the operating power supply Vcc. Switching element 901 between the power source Vcc and the resistor R21
Similarly, a switching element 902 is inserted between the power source Vcc and the resistor R22.

A carrier wave input signal (RF) is supplied between the terminal 911 and the ground. The local oscillation frequency signal of the I signal system is supplied between a terminal 912 (LO_I +) and a terminal 913 (LO_I−). The intermediate frequency signal of the I signal system is output from between terminal 915 and terminal 916 (IF_I). Further, the local oscillation frequency signal of the Q signal system is supplied between a terminal 922 (LO_Q +) and a terminal 923 (LO_Q−). The intermediate frequency signal of the Q signal system is output from between terminal 925 and terminal 926 (IF_Q).

In the mixer section of FIG. 9, when the detection output of the image signal level detection circuit 160 described with reference to FIGS. 1 and 6 is “0”, that is, the level of the image signal is less than a predetermined value,
The control signal CSm corresponding to the detection output is supplied to the switching elements 901 and 902, the switch is turned off, the power supply from the power source Vcc is cut off, and the operation of the image removal circuit is partially stopped (that is, the Q signal It is possible to reduce the power consumption corresponding to this stoppage by deactivating the system circuit).

On the other hand, when the detection output of the image signal level detection circuit 160 is “1”, that is, when the level of the image signal is equal to or higher than a predetermined value, the control signal CSm corresponding to the detection output is supplied to the switching elements 901 and 902. Turn on the switch to supply power from the power source Vcc and operate the entire image removal circuit (that is, operate both the I signal system and the Q signal system) to effectively suppress the image signal. To be able to.
In addition to the power supply stopping method described with reference to FIG. 9, a method such as turning off only Tr25, Tr27, and the constant current source 92 may be used.

FIG. 10 is a circuit diagram illustrating an example of the circuit configuration of the intermediate frequency complex filter 140 in the embodiment of FIG. 1, and FIG. 11 is a circuit diagram illustrating a circuit of one system configuring the circuit of FIG. .

The circuit of FIG. 11 is a circuit that is an element constituting the circuit of FIG. 10 by providing two of them and connecting them as will be described later (so-called cross-coupling between the two circuits with a resistor). The circuit in FIG. 11 belongs to the I signal system from the input signal of the first system 111 to the output signal of the first system 141 in FIG.
In FIG. 11, a terminal 1101 and a terminal 110 to which an input signal of the I signal system is applied.
2 is connected to the inverting input terminal and the non-inverting input terminal of the differential amplifier 11 through the corresponding resistors R11 and R12. The non-inverting output terminal of the differential amplifier 11 is connected to the inverting input terminal of the differential amplifier 11 through a parallel circuit of a capacitor C11 and a resistor R21. On the other hand, the inverting output terminal of the differential amplifier 11 is connected to the non-inverting input terminal of the differential amplifier 11 through a parallel circuit of a capacitor C12 and a resistor R22.

The non-inverting output terminal of the differential amplifier 11 is connected to the inverting input terminal of the differential amplifier 12 through the resistor R41, and the inverting output terminal of the differential amplifier 11 is connected to the non-inverting input terminal of the differential amplifier 12 through the resistor R42. It is connected to the. The non-inverting output terminal of the differential amplifier 12 is connected to the non-inverting input terminal of the differential amplifier 12 through the capacitor C21, and the inverting output terminal of the differential amplifier 12 is connected to the capacitor C22.
To the non-inverting input terminal of the differential amplifier 12.

Further, the inverting input terminal of the differential amplifier 11 is connected to the inverting output terminal of the differential amplifier 12 through the resistor R31, and the non-inverting input terminal of the differential amplifier 11 is connected to the non-inverting output terminal of the differential amplifier 12 through the resistor R32. Has been. The non-inverting output terminal and the inverting output terminal of the differential amplifier 12 are the output terminals 1.
105, 1106. The output between the output terminals 1105 and 1106 becomes an output as a low-pass filter. On the other hand, the non-inverting output terminal and the inverting output terminal of the differential amplifier 11 are connected to the output terminals 1103 and 1104, and between these output terminals 1103 and 1104. Becomes an output as a bandpass filter.

The circuit in FIG. 10 is configured by connecting two circuits having the same configuration as the circuit in FIG. As shown, the non-inverting output terminal of the differential amplifier 11 is connected to the inverting input terminal of the differential amplifier 211 via the switching element SW1 and the resistor R51, and the inverting output terminal of the differential amplifier 11 is connected to the switching element SW2 and the resistor R52. To the non-inverting input terminal of the differential amplifier 211.
The inverting input terminal of the differential amplifier 11 is connected to the inverting output terminal of the differential amplifier 211 via the switching element SW4 and the resistor R62, and the non-inverting input terminal of the differential amplifier 11 is connected via the switching element SW3 and the resistor R61. The differential amplifier 211 is connected to the non-inverting output terminal.

Similarly, the non-inverting output terminal of the differential amplifier 12 is connected to the inverting input terminal of the differential amplifier 212 via the switching element SW5 and the resistor R71, and the inverting output terminal of the differential amplifier 12 is connected to the switching element SW6 and the resistor R72. To the non-inverting input terminal of the differential amplifier 212.
The inverting input terminal of the differential amplifier 12 is connected to the inverting output terminal of the differential amplifier 212 via the switching element SW8 and the resistor R82, and the non-inverting input terminal of the differential amplifier 12 is connected via the switching element SW7 and the resistor R81. And connected to the non-inverting output terminal of the differential amplifier 212.

A circuit unit configured to include a portion in which the differential amplifier 11 and the differential amplifier 12 described above with reference to FIG. 11 are cascade-connected through resistors R41 and R42 is a filter function unit corresponding to the I signal system. There are a differential amplifier 211 and a differential amplifier 212 having the same configuration as the resistor R241.
, R 242 is a filter function unit corresponding to the Q signal system. The filter function unit corresponding to the Q signal system is the differential amplifier 211.
The terminals 2101 and 2102 corresponding to the inverting input terminal and the non-inverting input terminal are input terminals, and the terminals 2105 and 2106 corresponding to the non-inverting output terminal and the inverting output terminal of the differential amplifier 212 are output terminals. .

In order for the intermediate frequency filter 140 of FIG. 11 having the above configuration to function for the image signal extraction described with reference to FIG. 7, the phase difference (I The phase of the Q signal relative to the signal) is delayed from 90 ° to -90 ° (90 ° advance)
It is necessary to switch so that the input to the terminal 1101 and the terminal 1102 to which the input signal of the above-described I signal system is applied is switched so as to be inverted between both terminals by, for example, a switch. Can be done.

In the circuit of FIG. 10, the image signal level detection circuit 1 described with reference to FIGS.
When the detection output of 60 is “0”, that is, when the level of the image signal is less than a predetermined value, Q
The supply of the operating power supply (not shown) to the signal system is cut off, and the control signal CSf corresponding to the detected output is supplied to each of the switching elements SW1, SW2, SW3, SW4, SW5, SW6, SW
7 and SW8 are switched off to isolate the filter function unit corresponding to the Q signal system from the filter function unit corresponding to the I signal system.

In this way, the state in which the Q signal system is deactivated and insulated from the I signal system can be said to be a state in which only the circuit having the configuration of FIG. 11 operates.
When the detection output of the image signal level detection circuit 160 is, for example, a value indicating that the level of the image signal is lower than a predetermined value (a reference voltage value supplied from the reference voltage source 603 in FIG. 6), the image removal circuit 160 Since the operation mode is switched so as to partially cut off the supply of the operating power, the power consumption can be surely reduced in accordance with this stoppage, and the circuit section where the supply of the operating power is cut off is also in operation. Since it is insulated from the circuit section, there is no possibility of unnecessary interference or so-called wraparound with respect to signal processing.

As can be easily understood from the above description, the above-described invention is a reception method for performing signal processing including processing for frequency conversion of a received signal into an intermediate frequency signal having a frequency lower than that of the received signal, It can be thought of as a reception method characterized by changing the operation form of the image removal circuit for removing the image signal contained in the intermediate frequency signal according to the detection output of the level of the image signal.

According to the method of the present invention, if the operation mode is changed such as partially stopping the operation of the image removal circuit when the level of the detected image signal falls below a predetermined value, the power consumption corresponding to the stop can be reduced. Is planned.

It is a block diagram showing the structure of the receiver which concerns on the 1st Embodiment of this invention. It is a block diagram showing the structure of the receiver which concerns on the 2nd Embodiment of this invention. It is a block diagram showing the structure of the receiver which concerns on the 3rd Embodiment of this invention. It is a block diagram showing the structure of the receiver which concerns on the 4th Embodiment of this invention. It is a block diagram showing the structure of the receiver which concerns on the 5th Embodiment of this invention. FIG. 6 is a block diagram illustrating a configuration example of an image signal level detection circuit applied to the first to fifth embodiments of FIGS. 1 to 5. It is a figure for the phenomenon explanation regarding the process which extracts the image signal for detecting the level of the image signal in 1st Embodiment of FIG. FIG. 6 is a diagram for explaining phenomena related to a process of extracting an image signal for detecting the level of the image signal in the second to fifth embodiments of FIGS. 2 to 5; FIG. 2 is a circuit diagram illustrating a configuration example of a mixer unit in the embodiment of FIG. 1. FIG. 2 is a circuit diagram illustrating an example of a circuit configuration of an intermediate frequency complex filter in the embodiment of FIG. 1. It is a circuit diagram showing the circuit of one system which comprises the circuit of FIG.

Explanation of symbols

110, 210, 310, 410, 510 ... mixer section 120, 220, 320, 42
0, 520: Local oscillator 130, 230, 330, 430, 530 ... Frequency conversion circuit
140: Intermediate frequency complex filter 150, 250, 350, 450, 550 ... Image signal removal circuit 160, 260, 360, 460, 560 ... Image signal level detection circuit

Claims (9)

A reception apparatus including a frequency conversion circuit that converts a frequency of a received signal into a signal having a frequency lower than that of the received signal, and removing an image signal included in the signal frequency-converted by the frequency conversion circuit A circuit and an image signal level detection circuit for detecting the level of the image signal, and the image removal circuit is configured to operate in an operation mode corresponding to a detection output of the image signal level detection circuit. A receiving apparatus. The image removal circuit has two systems set so that signal phases are orthogonal between one system and the other system, and includes a complex filter corresponding to the two systems, The receiving apparatus according to claim 1, wherein the receiving apparatus is configured to remove an image signal by a complex filter. The image removal circuit has two systems, and a phase shifter is inserted in one of the two systems, and a system in which the phase shifter is inserted and a system in which the phase shifter is not inserted The receiving apparatus according to claim 1, wherein each of the outputs is added to remove an image signal. The receiving apparatus according to claim 3, wherein the two systems of the image removal circuit include a band-pass filter having a predetermined frequency inserted in each system. At least one of the systems is provided with two carrier signal transmission systems in which a phase shifter is inserted so as to guide the received signal to the frequency conversion circuit, and the image removal circuit includes the two carrier signal transmission systems. 2. The receiving apparatus according to claim 1, wherein two receiving systems are provided, and the outputs of the two systems are added to remove an image signal. 6. The receiving apparatus according to claim 5, wherein in the two systems of the image removal circuit, a band-pass filter having a predetermined frequency is inserted in each system. The image removal circuit is configured to output the 2 in accordance with a detection output of the image signal level detection circuit.
The receiving device according to any one of claims 2 to 6, wherein the receiving device is configured to switch the operation mode so as to cut off the supply of the operating power to any one of the two systems. . The image removal circuit is configured to output the 2 in accordance with a detection output of the image signal level detection circuit.
3. The system according to claim 2, wherein the operation mode is switched so as to cut off the supply of the operation power to any one of the two systems and to insulate the one system from the other system. The receiving apparatus as described in any one of -6. A reception method for performing signal processing including processing for converting a received signal into a signal having a frequency lower than that of the received signal, the image signal included in the signal processed by the signal processing including the frequency conversion processing The receiving method is characterized in that the mode of operation of the image removal circuit for removing image is changed according to the detection output of the level of the image signal.

Images