JP2008028525A - Radio signal receiver unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio signal receiver unit which avoids the reception sensitivity suppression of a desired wave, due to a mutual modulation distortion generated by an unnecessary wave having larger receiving power than the desired wave. <P>SOLUTION: The radio signal receiver unit includes: a high frequency amplifier for amplifying a received radio frequency signal; an intermediate frequency amplifier for amplifying an intermediate frequency signal obtained by converting the radio frequency signal by means of a frequency conversion circuit; a first band pass filter for passing signals in a band including the frequency of the desired wave among the amplified intermediate frequency signals; a band rejection filter for selectively rejecting signals in the band including the frequency of the desired wave among the amplified intermediate frequency signals and for passing signals in other bands; a pseudo distortion addition means for adding a pseudo mutual modulation distortion by amplifying the intermediate frequency signal having passed the band rejection filter; a second band pass filter for passing signals in the band including the frequency of the desired wave among signals on which the pseudo mutual modulation distortion is added by the pseudo distortion addition means; and a subtractor for subtracting the output signal of the second band rejection filter from the output signal of the intermediate frequency amplifier, and for supplying the obtained signal to processing in a demodulator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio signal receiving apparatus provided in a terminal apparatus and a base station apparatus constituting a mobile communication system that provides a mobile phone service, a network connection service using a wireless LAN, and the like, and particularly used for individual services. The present invention relates to a technique for removing intermodulation distortion related to an unnecessary wave having a frequency other than a desired wave.

  If the intermodulation distortion component generated when an unwanted wave having a frequency different from this desired wave is input to the amplifier together with the desired wave, if it is transmitted as a radio signal as it is, it will not be possible to satisfy the requirements stipulated by the Radio Law. Various proposals have been made for a method of eliminating intermodulation distortion in a transmission apparatus, and the frequency of a radio signal transmitted from the transmission apparatus is strictly unified.

In addition, a technology to adjust the transmission power to the minimum necessary so that it does not become interference power for other lines using the same frequency band is also provided, and the influence of interference power on adjacent frequencies etc. is reduced. Yes.
Therefore, in the receiving apparatus, the received signal is processed on the assumption that the desired wave arrives dominantly.

However, in an environment where a plurality of business operators are confused and provide wireless communication services as in recent years, wireless signals of various frequencies are transmitted by the transmission devices for each wireless communication service. When the received radio frequency signal is amplified by the high frequency amplifier, intermodulation distortion may occur.
For example, as shown in FIG. 11, an unnecessary wave source (for example, base stations a and b) is more suitable than a transmitting apparatus (for example, base station O) that transmits a radio signal of a desired wave fo that the mobile communication terminal is to receive. In a near environment, the received power of the unwanted waves f _i1 and f _i2 arriving from these unwanted wave sources becomes much larger, and when input to the high frequency amplifier and amplified as it is, intermodulation distortion occurs, and the signal of the desired wave is generated. The sensitivity to is suppressed.

  In the conventional receiving apparatus, as shown in FIG. 12, a high-frequency filter (not shown) provided in front of the high-frequency amplifier 401 or a local oscillator 402, a multiplier 403, and a filter (for one-side waveband removal) 404 is used. A band-pass filter 407 provided after the intermediate frequency amplifier 405 provided for amplifying the generated intermediate frequency signal selectively demodulates the received signal related to the desired wave via the intermediate frequency amplifier 406 through the demodulator 408. By using this process, it is attempted to remove intermodulation distortion together with unnecessary waves other than the desired wave.

Further, since the intermodulation distortion occurs when the amplifier is saturated, for example, by controlling the gain of the high-frequency amplifier 401 in accordance with the received signal power, the saturation of the high-frequency amplifier 401 is prevented and the intermodulation is prevented. A technique for suppressing the occurrence of distortion has also been proposed (see Patent Document 1).
Further, it is well known that the occurrence of intermodulation distortion can be suppressed by adopting an extremely high linearity amplifier as the high-frequency amplifier 401.

On the other hand, in systems that transmit and receive radio signals between fixed stations, such as terrestrial microwave communication, a signal related to unnecessary waves is extracted by directing a separate parabolic antenna to the unnecessary wave source, and the extracted interference signals are received signals. By subtracting from the offset, unnecessary waves are removed.
JP-A-10-126301

  By the way, as shown in FIG. 12, in the method of removing the intermodulation distortion component by the band-pass filter 407, it is very difficult to remove the intermodulation distortion component that appears in the vicinity of the desired wave. This is because a band-pass filter must pass a signal in a frequency band near the desired wave to some extent in order to efficiently pass the signal of the desired wave. When the reception power of the unnecessary wave is larger than that of the desired wave, an intermodulation distortion component having a magnitude that cannot be ignored appears in the vicinity of the desired wave, and the reception sensitivity for the desired wave is lowered.

  In addition, in recent years, the frequency allocation to each business operator is becoming denser as in recent years, and it is very difficult to select only a received signal having a desired frequency with a high-frequency filter. This is because, in such a narrow-band high-frequency filter, the allowable propagation distance is reduced due to an increase in in-band passing loss, or the installation location is limited or portable due to a structural increase in size. This is because sex is impaired.

  On the other hand, even if the gain of the high-frequency amplifier is controlled in accordance with the received power of the desired wave by applying the technique of Patent Document 1, if an unnecessary wave that far exceeds the received power of the desired wave arrives, it cannot be ignored. It is considered that an intermodulation distortion component having a magnitude is generated. Conversely, if the gain control of the high-frequency amplifier is performed in accordance with the received power of the unwanted wave, the received signal of the desired wave cannot be sufficiently amplified.

Of course, if an ideal linear high-frequency amplifier is used, the occurrence of intermodulation distortion can be avoided, but it has a wide dynamic range, low power consumption, and low cost required for a high-frequency amplifier constituting a receiver of a mobile communication system. However, a high-frequency amplifier having both high linearity has not been realized yet.
Also, in the mobile communication system, the desired wave signal source and the unnecessary wave source as viewed from the receiving device provided in the mobile communication terminal move from moment to moment, so the above-described unnecessary wave removal technology in terrestrial microwave communication is applied as it is. It is difficult to do.

  An object of the present invention is to provide a radio signal receiving apparatus capable of avoiding suppression of reception sensitivity of a desired wave due to intermodulation distortion caused by an unnecessary wave having a reception power larger than that of the desired wave.

A first radio signal receiving apparatus according to the present invention includes a high frequency amplifier, a frequency conversion circuit, an intermediate frequency amplifier, a first band pass filter, a band rejection filter, a pseudo distortion adding means, a second band, It consists of a pass filter and a subtractor.
The principle of the first radio signal receiving apparatus according to the present invention is as follows.
The high frequency amplifier amplifies the received radio frequency signal. The frequency conversion circuit converts a radio frequency signal into an appropriate intermediate frequency signal. The intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the frequency conversion circuit. The first band pass filter passes a signal in a band including a frequency of a desired wave among the intermediate frequency signals output from the intermediate frequency amplifier. The band rejection filter selectively blocks signals in the band including the frequency of the desired wave from the intermediate frequency signal output from the intermediate frequency amplifier, and passes signals in other bands. The pseudo distortion adding means adds pseudo intermodulation distortion by amplifying the intermediate frequency signal that has passed through the band rejection filter. The second band-pass filter passes a signal in a band including a frequency of a desired wave among the signals to which the pseudo intermodulation distortion is added by the pseudo distortion adding unit. The subtracter subtracts the output signal of the second bandpass filter from the output signal of the intermediate frequency amplifier, and uses the obtained signal for processing of the demodulator.

The operation of the first radio signal receiving apparatus configured as described above is as follows.
The radio frequency reception signal amplified by the high frequency amplifier is converted into an intermediate frequency signal by the frequency conversion circuit, amplified by the intermediate frequency amplifier, and then divided into two systems, one of which is hereinafter referred to as the main system. The signal is passed to the first band pass filter, and the other (hereinafter referred to as sub system) signal is passed to the pseudo distortion adding means via the band rejection filter. In the band rejection filter, the signal of the band corresponding to the desired wave is removed from the signal of the sub system and the signal corresponding to the unnecessary wave is passed. Therefore, the intermediate frequency signal that has passed through the band rejection filter is added to the pseudo distortion adding means. By amplifying at, pseudo intermodulation distortion corresponding to the intermodulation distortion appearing in the frequency band corresponding to the desired wave when a radio frequency signal including unwanted waves is amplified by the high frequency amplifier can be added. In this way, by passing the intermediate frequency signal to which the pseudo intermodulation distortion is added through the second band pass filter, the intermodulation distortion component appearing in the band corresponding to the desired wave is extracted, and this is described above. By subtracting from the main system signal that has passed through the first bandpass filter, the intermodulation distortion component included in the frequency band including the desired wave of the main system signal is canceled, and the reception sensitivity relating to the signal of the desired wave Suppression can be avoided.

A second radio signal receiving apparatus according to the present invention includes a first-stage high-frequency amplifier, compensation signal generating means, a subtractor, a second-stage high-frequency amplifier, a first frequency conversion circuit, an intermediate frequency amplifier, The compensation signal generation means includes a band rejection filter, a second frequency conversion circuit, and a pseudo distortion generation means.
The principle of the second radio signal receiving apparatus according to the present invention is as follows.

  The first stage high frequency amplifier amplifies the received radio frequency signal. The compensation signal generating means generates a compensation signal for compensating for the intermodulation distortion generated in the first stage high frequency amplifier. The subtracter subtracts the compensation signal from the output signal of the first stage high frequency amplifier. The second stage high frequency amplifier amplifies the radio frequency signal output from the subtractor. The first frequency conversion circuit converts the output signal of the second-stage high-frequency amplifier into a signal having an appropriate intermediate frequency. The intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the frequency conversion circuit. The band pass filter passes the signal in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and supplies the signal to the demodulator. In the compensation signal generating means, the band rejection filter selectively blocks signals in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and passes signals in other bands. The second frequency conversion circuit generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting the intermediate frequency signal that has passed through the band rejection filter. The pseudo distortion generating means generates the compensation signal including pseudo intermodulation distortion by amplifying the radio frequency signal obtained by the second frequency conversion circuit, and inputs it to the subtractor.

The operation of the second radio signal receiving apparatus configured as described above is as follows.
The radio frequency reception signal amplified by the first stage high frequency amplifier is subtracted by the subtractor from the compensation signal generated by the compensation signal generation means, and then converted to an intermediate frequency signal by the frequency conversion circuit. After being amplified by the frequency amplifier, it is divided into two systems. One of these two intermediate frequency signals (hereinafter referred to as the main system) is subjected to a demodulator process via the first band-pass filter, and the other (hereinafter referred to as the sub system) is used to generate a compensation signal. The compensation signal is generated by the means.

  In this compensation signal generation means, the signal of the above-mentioned sub system passes through the band rejection filter, so that the signal in the band corresponding to the desired wave is removed and becomes a signal including only the frequency component corresponding to the unnecessary wave. . The intermediate frequency signal that has passed through the band rejection filter is returned to a radio frequency signal by the second frequency conversion circuit, and is amplified by the pseudo distortion adding means, thereby amplifying the radio frequency signal including unnecessary waves by the high frequency amplifier. In this case, a compensation signal including pseudo intermodulation distortion corresponding to the intermodulation distortion appearing in the frequency band corresponding to the desired wave can be generated. In this way, the compensation signal is generated based on the intermodulation distortion component included in the frequency band including the desired wave of the main system signal that precedes the time required for the compensation signal generation processing by the compensation signal generation means described above. The compensation signal is input to the subtracter and subtracted from the output signal of the first-stage high-frequency amplifier described above, whereby the intermodulation related to the unnecessary wave appears in the output signal of the first-stage high-frequency amplifier. It is possible to cancel distortion components and avoid reception sensitivity suppression related to a desired wave signal.

  In the second radio signal receiving apparatus described above, a state where the intermodulation distortion is canceled by the compensation signal and a state where the intermodulation distortion appears in the output of the band pass filter alternately appear. This is because the unnecessary signal and the intermodulation distortion component related to the unnecessary wave appear in the compensation signal generated by referring to the state where the intermodulation distortion related to the unnecessary wave is canceled together with the unnecessary wave by the compensation signal. Therefore, the unnecessary wave included in the radio frequency signal output from the first-stage high-frequency amplifier at the timing when the compensation signal is input to the subtractor and the intermodulation distortion related to the unnecessary wave remain without being canceled, The compensation signal obtained by referring to the state where the unnecessary wave and the intermodulation distortion remain in this way is included in the radio frequency signal output from the first-stage high-frequency amplifier at the timing when it is input to the subtractor. This is because the unwanted wave and the intermodulation distortion related to the unwanted wave are canceled out.

  A third radio signal receiving apparatus according to the present invention includes a distributor, a main system first stage high frequency amplifier, a compensation signal generation means, a delay circuit, a subtractor, a main system next stage high frequency amplifier, and a main system frequency converter. Circuit, a main intermediate frequency amplifier, and a band-pass filter. The compensation signal generation means includes a sub first-stage high-frequency amplifier, a sub-system second-stage high-frequency amplifier, a first frequency conversion circuit, and a sub-system intermediate. A frequency amplifier, a band rejection filter, a second frequency conversion circuit, and pseudo-distortion generation means are configured.

The principle of the third radio signal receiving apparatus according to the present invention is as follows.
The distributor branches the received radio frequency signal into two systems, a main system and a sub system. The main system first stage high frequency amplifier amplifies the radio frequency signal of the main system. The compensation signal generating means generates a compensation signal for compensating for the intermodulation distortion generated in the main system first stage high frequency amplifier. The delay circuit is disposed between the distributor and the main system first-stage high-frequency amplifier, and applies a delay corresponding to the time required for the compensation signal generation processing by the compensation signal generation means to the main system radio frequency signal. The subtracter subtracts the compensation signal from the output signal of the main system first stage high frequency amplifier. The main system next stage high frequency amplifier amplifies the radio frequency signal output from the subtractor. The main system frequency conversion circuit converts the output signal of the main system next-stage high-frequency amplifier into a signal having an appropriate intermediate frequency. The main system intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the main system frequency conversion circuit. The band pass filter passes the signal in the band including the frequency of the desired wave among the intermediate frequency signals output from the main system intermediate frequency amplifier, and supplies the signal to the demodulator. In the compensation signal generation means, the sub-system first-stage high-frequency amplifier amplifies the sub-system radio frequency signal. The sub-system next-stage high-frequency amplifier amplifies the radio frequency signal output from the sub-system first-stage high-frequency amplifier. The first frequency conversion circuit converts the output signal of the sub-system next-stage high-frequency amplifier into a signal having an appropriate intermediate frequency. The sub system intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the first frequency conversion circuit. The band rejection filter selectively blocks a signal in a band including the frequency of the desired wave from the intermediate frequency signal output from the sub system intermediate frequency amplifier, and passes a signal in another band. The second frequency conversion circuit generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting the intermediate frequency signal that has passed through the band rejection filter. The pseudo distortion generating means generates the compensation signal including pseudo intermodulation distortion by amplifying the radio frequency signal obtained by the second frequency conversion circuit, and inputs it to the subtractor.

The operation of the third radio signal receiving apparatus configured as described above is as follows.
Prior to the main system signal being input to the subtractor after being amplified by the main system first stage high frequency amplifier, the sub system radio frequency signal is input to the compensation signal generating means. After the amplification by the high-frequency amplifier and the sub-system next-stage high-frequency amplifier, the frequency conversion by the first frequency conversion circuit, and the amplification by the sub-system intermediate frequency amplifier, the unwanted wave component and the intermodulation distortion related to the unnecessary wave by the band rejection filter Ingredients are removed. When the signal extracted in this way is converted back to a radio frequency signal by the second frequency conversion circuit and amplified by the pseudo distortion adding means, the radio frequency signal including unnecessary waves is amplified by the high frequency amplifier. A compensation signal including pseudo intermodulation distortion corresponding to the intermodulation distortion appearing in the frequency band corresponding to the desired wave can be generated.

  The compensation signal obtained in this way is input to the subtracter, and is subtracted from the output signal of the main system first stage high frequency amplifier delayed by the time required for the compensation signal generation processing described above by the delay circuit. Along with the unwanted wave appearing in the amplifier output signal, the intermodulation distortion component related to this unwanted wave is canceled, and the unwanted wave and the radio frequency signal that does not contain the intermodulation distortion component appearing in the desired frequency band due to the unwanted wave are mainly used The input intermediate frequency signal input to the system frequency conversion circuit can be used for the demodulator process via the main system intermediate frequency amplifier and bandpass filter, thus avoiding reception sensitivity suppression for the desired signal. can do.

A fourth radio signal receiving apparatus according to the present invention includes a compensation signal generating means, a synthesizer, a high frequency amplifier, a first frequency conversion circuit, an intermediate frequency amplifier, and a band pass filter, and a compensation signal. The generation means includes a band rejection filter, a second frequency conversion circuit, and an inverting input means.
The principle of the fourth radio signal receiving apparatus according to the present invention is as follows.

The synthesizer synthesizes the received radio frequency signal and the compensation signal generated by the compensation signal generation means. The high frequency amplifier amplifies a radio frequency signal output from the combiner.
The first frequency conversion circuit that converts the output signal of the high-frequency amplifier into a signal having an appropriate intermediate frequency, and the intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the frequency conversion circuit. The band pass filter passes the signal in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and supplies the signal to the demodulator. In the compensation signal generating means, the band rejection filter selectively blocks signals in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and passes signals in other bands. The second frequency conversion circuit generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting the intermediate frequency signal that has passed through the band rejection filter. The inverting input unit generates the compensation signal as a signal obtained by inverting the phase of the radio frequency signal based on the radio frequency signal obtained by the second frequency conversion circuit, and inputs the compensation signal to the synthesizer.

The operation of the fourth radio signal receiving apparatus configured as described above is as follows.
The radio frequency received signal is subjected to amplification processing by a high frequency amplifier via a synthesizer, further converted to an intermediate frequency signal by a frequency conversion circuit, amplified by the intermediate frequency amplifier, and then divided into two systems. One of these two intermediate frequency signals (hereinafter referred to as the main system) is subjected to a demodulator process via the first band-pass filter, and the other (hereinafter referred to as the sub system) is used to generate a compensation signal. The compensation signal is generated by the means.

  In this compensation signal generation means, the signal of the above-mentioned sub system passes through the band rejection filter, so that the signal in the band corresponding to the desired wave is removed and becomes a signal including only the frequency component corresponding to the unnecessary wave. . The intermediate frequency signal that has passed through the band rejection filter is converted back to a radio frequency signal by the second frequency conversion circuit, and this is subjected to processing of the inverting input means, thereby causing an unnecessary wave component that causes intermodulation distortion in the high frequency amplifier. A radio frequency compensation signal with the phase inverted can be obtained.

  In this way, compensation is performed based on a signal in a frequency band other than the frequency band including the desired wave of the sub-system signal corresponding to the main system signal preceding the main system signal by the time required for the compensation signal generation processing by the compensation signal generation means described above. By generating a signal and synthesizing this compensation signal with the received signal to cancel out the unwanted wave component, it is possible to prevent the intermodulation distortion component related to the unwanted wave from being generated in the high frequency amplifier and to receive the signal related to the desired wave signal. Sensitivity suppression can be avoided.

  In the fourth radio signal receiving apparatus described above, the state where the unwanted wave component is canceled by the compensation signal and the state where the intermodulation distortion appears in the output of the bandpass filter alternately appear. This is because an unnecessary wave component does not appear in the compensation signal generated by referring to the state in which the unnecessary wave is canceled by the above-described compensation signal, and is input to the high-frequency amplifier at the timing when the compensation signal is synthesized. Intermodulation distortion occurs because unnecessary waves remain in the radio frequency signal without being canceled, and the compensation signal obtained by referring to the state where the unnecessary waves and the intermodulation distortion remain is synthesized This is because, since unnecessary waves are removed, intermodulation distortion does not occur in the high-frequency amplifier.

  A fifth radio signal receiving apparatus according to the present invention includes a distributor, a compensation signal generating means, a combiner, a delay circuit, a high frequency amplifier, a main system frequency converter circuit, a main system intermediate is an amplifier, And a sub-pass high-frequency amplifier, a first frequency conversion circuit, a sub-system intermediate frequency amplifier, a band rejection filter, a second frequency conversion circuit, and an inverting input. Means.

The principle of the fifth radio signal receiving apparatus according to the present invention is as follows.
The distributor branches the received radio frequency signal into two systems, a main system and a sub system. The synthesizer synthesizes the main system radio frequency signal and the compensation signal generated by the compensation signal generation means. The delay circuit is arranged between the distributor and the combiner, and gives a delay corresponding to the time required for the compensation signal generation processing by the compensation signal generation means to the main radio frequency signal. The high frequency amplifier amplifies a radio frequency signal output from the combiner. The main system frequency conversion circuit converts the output signal of the high-frequency amplifier into a signal having an appropriate intermediate frequency. The main system intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the main system frequency conversion circuit. The band pass filter passes the signal in the band including the frequency of the desired wave among the intermediate frequency signals output from the main system intermediate frequency amplifier, and supplies the signal to the demodulator. In the compensation signal generating means, the sub system high frequency amplifier amplifies the sub system radio frequency signal. The first frequency conversion circuit converts the output signal of the sub-system high-frequency amplifier into a signal having an appropriate intermediate frequency. The sub system intermediate frequency amplifier amplifies the intermediate frequency signal obtained by the first frequency conversion circuit. The band rejection filter selectively blocks a signal in a band including the frequency of the desired wave from the intermediate frequency signal output from the sub system intermediate frequency amplifier, and passes a signal in another band. The second frequency conversion circuit generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting the intermediate frequency signal that has passed through the band rejection filter. The inverting input unit generates the compensation signal as a signal obtained by inverting the phase of the radio frequency signal based on the radio frequency signal obtained by the second frequency conversion circuit, and inputs the compensation signal to the synthesizer.

The operation of the fifth radio signal receiving apparatus configured as described above is as follows.
Prior to the main system signal being input to the synthesizer, the sub system radio frequency signal is input to the compensation signal generating means. In this compensation signal generating means, amplification by the sub system high frequency amplifier and the first frequency conversion circuit are performed. After the frequency conversion by the above and the amplification by the sub system intermediate frequency amplifier, the unnecessary wave component and the intermodulation distortion component related to the unnecessary wave are taken out by the band rejection filter. The signal extracted in this way is converted back to a radio frequency signal by the second frequency conversion circuit, and is subjected to processing of unnecessary wave extraction means, thereby generating a compensation signal including an unnecessary wave component whose phase is inverted. Can do.

  The compensation signal obtained in this way is input to the synthesizer and synthesized with the main radio frequency signal delayed by the time required for the above-mentioned compensation signal generation processing by the delay circuit, thereby allowing the main radio frequency amplifier to It is possible to remove unnecessary waves from the input radio frequency signal and prevent the occurrence of intermodulation distortion due to the influence of unnecessary waves. Accordingly, since a radio frequency signal containing neither an unnecessary wave nor an intermodulation distortion component can be input to the main frequency conversion circuit, similarly, an intermediate frequency signal containing neither an unnecessary wave nor an intermodulation distortion component is converted to the main system intermediate frequency. It can be used for processing of the demodulator via the amplifier and the bandpass filter, and reception sensitivity suppression regarding the signal of the desired wave can be reliably avoided.

As described above, in the first radio signal receiving apparatus, the intermodulation distortion generated in a pseudo manner with respect to the intermediate frequency signal is subtracted, so that an unnecessary wave having a received power larger than that of the desired wave is brought close to the desired wave. Since the appearing intermodulation distortion component is removed, it is possible to avoid suppression of reception sensitivity of a desired wave with a relatively small circuit scale.
On the other hand, in the second and third radio signal receiving apparatuses, by generating a compensation signal using a high-frequency amplifier, a pseudo distortion component that is very close to the intermodulation distortion component included in the radio frequency signal to be compensated is generated. The intermodulation distortion component that appears in the vicinity of the desired wave due to an unnecessary wave having a received power larger than that of the desired wave can be removed using the compensation signal that is included.

Further, in the fourth and fifth radio signal receiving apparatuses, the generation of the intermodulation distortion itself can be prevented by removing the unnecessary wave component by the compensation signal prior to the input of the radio frequency signal to the high frequency amplifier. it can.
In particular, in the third and fifth radio signal receiving apparatuses, a delay circuit is arranged in the main system, and the timing at which the intermediate frequency signal of the sub system used for generating the compensation signal is referred to and the generated compensation signal By matching the timing with which the radio frequency signal of the main system is compensated, the intermodulation distortion component or unnecessary wave component that appears in the vicinity of the desired wave is extremely high even for a fast signal with a short sampling period applied in the demodulator. It can be removed with accuracy.

  In addition, in this way, it has become possible to avoid suppression of reception sensitivity of a desired wave due to an intermodulation distortion component that appears in the vicinity of the desired wave due to an unnecessary wave having a higher reception power than the desired wave. Even in an environment where mobile communication services using close frequency bands are provided, it is possible to reliably receive radio signals of desired waves used in individual services, so that serviceability for users of mobile communication systems Can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 shows a first embodiment of a radio signal receiving apparatus according to the present invention.
Note that among the components shown in FIG. 1, the same components as those shown in FIG. 12 are denoted by the reference numerals shown in FIG. 12, and description thereof is omitted.

  In the radio signal receiving apparatus shown in FIG. 1, a radio frequency (RF) received signal is amplified by a high frequency first-stage low noise amplifier 201 corresponding to the high frequency amplifier 401 shown in FIG. Is converted into an intermediate frequency signal. After the intermediate frequency signal thus obtained is amplified by the intermediate frequency amplifier 405, the signal of the main system used for the desired wave extraction process similar to the conventional one and the sub signal used for the compensation signal generation process described later are used. It is divided into system signals.

  In the process of passing through the band rejection filter 202 shown in FIG. 1, the sub-system signal described above is subjected to amplification processing by the intermediate frequency amplifier 203 after the components of the pass band of the band pass filter 407 are removed. The The intermediate frequency signal amplified by the intermediate frequency amplifier 203 is inverted and input to the adder 207 via the band pass filter 204 and the variable attenuator 205 which are equivalent to the band pass filter 407 described above. Synthesized with the signal.

Hereinafter, an operation for compensating for intermodulation distortion generated in the amplification process by the high-frequency first-stage low-noise amplifier 201 using the compensation signal generated based on the sub-system signal shown in FIG. 1 will be described.
FIG. 2 is a diagram illustrating an operation for compensating for intermodulation distortion.
As shown in FIG. 2 (a), when the unwanted waves f _i1 and f _i2 having received power larger than the received power of the desired wave fo are received together with the desired wave fo, the RF received signal is shown in FIG. When the signal is amplified by the high-frequency first-stage low-noise amplifier 201, due to the influence of these unnecessary waves f _i1 and f _i2 , intermodulation distortion components are generated in a wide frequency band indicated by shading in FIG. appear.

A part of such intermodulation distortion component passes through a band-pass filter 407 provided in an intermediate frequency band corresponding to a desired wave as shown in FIG. The container 207 is reached.
On the other hand, the pseudo-distortion generated in the process of being amplified by the intermediate frequency amplifier 203 shown in FIG. 1 is applied to the signal that has passed through the band rejection filter 202 shown in FIG. 1 (see FIG. 2D). Components are superimposed (see FIG. 2 (e)).

  When the intermediate frequency signal including the pseudo distortion component generated in this way passes through the band pass filter 204 shown in FIG. 1, the intermodulation remaining in the main system signal shown in FIG. A compensation signal including a frequency component corresponding to the distortion component is obtained (see FIG. 2 (f)), and the amplitude of the compensation signal is appropriately adjusted by the variable attenuator 205 and inverted and input to the adder 207. Only the modulation distortion component can be canceled out selectively.

As a result, as shown in FIG. 2A, it is possible to avoid reception sensitivity suppression related to a desired wave and obtain a good demodulation result even in a reception environment in which unnecessary waves arrive predominantly. In particular, since the compensation signal is generated by the intermediate frequency circuit, the circuit scale can be suppressed, and a low-cost and small-sized radio signal receiving apparatus can be realized.
In the configuration shown in FIG. 1, the error detection unit 206 detects an error in the demodulator 408 and adjusts the attenuation rate of the variable attenuator 205 according to the detection result, thereby generating the error by the intermediate frequency amplifier 203. Differences between the simulated intermodulation distortion and the intermodulation distortion generated in the high-frequency first-stage low-noise amplifier 201 and the transmittance in the two band-pass filters 204 are corrected.
(Second Embodiment)
FIG. 3 shows a second embodiment of the radio signal receiving apparatus according to the present invention. FIG. 4 is a diagram illustrating an operation for compensating for intermodulation distortion.

3 that are the same as those shown in FIG. 1 and FIG. 12 are denoted by the same reference numerals as those shown in FIG. 1 and FIG.
In the radio signal receiving apparatus shown in FIG. 3, the sub-system signal is input to the multiplier 213 via the band rejection filter 202 and the variable attenuator 205, multiplied by the output signal of the local oscillator 402, and again the radio frequency. Return to the signal. After that, the radio frequency signal from which the one-side waveband is removed by the filter 214 is amplified by the high frequency amplifier 215, inverted and input to the adder 211, and synthesized with the output signal of the high frequency first stage low noise amplifier 201. .

  In the radio signal receiving apparatus configured as described above, the state where the output of the high-frequency first-stage low noise amplifier 201 appears as it is as the output of the adder 211 (hereinafter referred to as state 0), as indicated by the white arrow in FIG. Then (see FIGS. 4 (a) and 4 (b)), as shown in FIG. 4 (d), the signal of the sub system including the unwanted wave and the intermodulation distortion component is amplified by the high frequency amplifier 215 as described above. As a result, a compensation signal in which intermodulation distortion appears in the band corresponding to the desired wave is obtained (see FIG. 4E).

  Then, the compensation signal is inverted and input to the adder 211 and synthesized with the output of the high-frequency first-stage low-noise amplifier 201, so that the band corresponding to the unnecessary wave and the desired wave is shown in FIG. A transition is made to a state where a signal from which the intermodulation distortion component has been removed (hereinafter referred to as state 1) is obtained (see FIGS. 4A and 4B). In such a state 1, as shown in FIG. 4 (c ′), the unwanted wave and the intermodulation distortion component associated therewith can be removed from the intermediate frequency signal of the main system. Can be avoided.

On the other hand, in the intermediate frequency signal of the sub system at this time, only the intermodulation distortion component that appeared in the compensation signal obtained in the previous state 0 corresponding to the band other than the band corresponding to the desired wave appears. The components corresponding to the unnecessary waves f _i1 and f _i2 do not appear (see FIG. 4 (d ′)). Accordingly, the components corresponding to the unnecessary waves f _i1 and f _i2 do not appear in the compensation signal generated based on the signal of such a sub system (see FIG. 4 (e ′)), so the output of the adder 211 The signal is almost the same as the output signal of the high-frequency first-stage low noise amplifier 201, and shifts to the state 0 again.

In this state 0, as shown in FIG. 4C, the intermodulation distortion component that has passed through the band-pass filter 407 remains, and sensitivity suppression related to the desired wave occurs. On the other hand, based on the sub-system intermediate frequency signal obtained in this state 0, as described above, a compensation signal is generated in consideration of the unwanted wave and the intermodulation distortion component associated therewith.
As described above, the radio signal receiving apparatus shown in FIG. 3 has a state 1 in which the influence of the unnecessary wave is canceled by the synthesis with the compensation signal, and a state 0 for generating the compensation signal in consideration of the influence of the unnecessary wave. For example, by appropriately adjusting the time required for the generation process of the compensation signal so that the cycle in which the state 0 and the state 1 are repeated and the sampling cycle in the demodulator 408 satisfy an appropriate relationship. Thus, it is possible to prevent the sensitivity suppression generated in the state 0 from affecting the processing of the demodulator 408.

In addition, since the radio signal receiving apparatus shown in FIG. 3 uses the high-frequency amplifier 215 having characteristics approximate to those of the high-frequency first-stage low-noise amplifier 201 for generating the compensation signal, A compensation signal including a component very close to the modulation distortion can be obtained. Thereby, in the state 1, the unnecessary wave and the intermodulation distortion component can be almost completely removed, and the sensitivity suppression regarding the desired wave can be surely eliminated.
(Third embodiment)
FIG. 5 shows a third embodiment of a radio signal receiving apparatus according to the present invention. FIG. 6 is a diagram illustrating an operation for compensating for intermodulation distortion.

7 that are the same as those shown in FIGS. 1, 3, and 12 are denoted by the same reference numerals as those shown in FIGS. 1, 3, and 12, and description thereof is omitted. To do.
In the radio signal receiving apparatus shown in FIG. 5, the RF reception signal is divided into a main system signal used for reception processing from the high-frequency first-stage low noise amplifier 201 to the demodulator 408 via the delay line 217 by the distributor 216, and The signal is distributed to the sub-system signal used for processing by the compensation signal generation unit 210.

  In the compensation signal generation unit 210 shown in FIG. 5, the signal of the sub system is amplified by the high frequency first stage low noise amplifier 218 and the high frequency amplifier 219 (see FIG. 6B ′), and then the multiplier 220 and the local oscillator 402. After being frequency-converted by, the one-side waveband is removed by passing through the filter 221, and is input to the band rejection filter 202 via the intermediate frequency amplifier 222. The signal that has passed through the bandstop filter 202 (see FIG. 6C) is input to the multiplier 213 via the variable attenuator 205, returned to the radio frequency again, and then further amplified by the high frequency amplifier 215. Then, it is inverted and input to the adder 211 as a compensation signal as shown in FIG.

In the radio signal receiving apparatus shown in FIG. 5, the main system signal (see FIGS. 6A and 6B) amplified by the high-frequency first-stage low-noise amplifier 201 after being delayed by the delay line 217, and the above-mentioned And the compensated signal are combined. Therefore, by appropriately adjusting the delay time by the delay line 217, the output signal of the high-frequency first-stage low noise amplifier 201 and the compensation signal generated based on the radio frequency signal received at the corresponding timing are synthesized and controlled. it can be canceled to unnecessary waves f _i1, f _i2 and intermodulation distortion component generated in a band corresponding to the desired wave along with this incoming. As a result, as shown in FIG. 6 (e), a synthesized signal in which the intermodulation distortion component does not appear in the band corresponding to the desired wave can be obtained, so that this synthesized signal is passed through the band-pass filter 407. As a result, as shown in FIG. 6 (f), a signal including only the desired wave component can be provided to the processing of the demodulator 408, and sensitivity suppression regarding the desired wave can be reliably avoided.

(Fourth embodiment)
FIG. 7 shows a fourth embodiment of a radio signal receiving apparatus according to the present invention. FIG. 8 is a diagram illustrating an operation for compensating for intermodulation distortion.
7 that are the same as those shown in FIGS. 1, 3, and 12 are denoted by the same reference numerals as those shown in FIGS. 1, 3, and 12, and description thereof is omitted. To do.

In the radio signal receiving apparatus shown in FIG. 7, the compensation signal generated based on the output signal of the high frequency amplifier 215, that is, the intermediate frequency signal of the sub system that has passed through the band rejection filter 202, Is inverted and input to an adder 211 provided in the preceding stage, and synthesized with an RF reception signal.
Therefore, in the radio signal receiving apparatus shown in FIG. 7, as in the radio signal receiving apparatus shown in FIG. 3, the state 0 in which the intermodulation distortion component due to unnecessary waves remains in the output of the bandpass filter 407 and the mutual signal The state 1 in which the modulation distortion component does not appear at the output of the band pass filter 407 is repeated alternately.

  In the radio signal receiving apparatus shown in FIG. 7, as shown in FIGS. 8A to 8F, in the state 0, an unnecessary wave component included in the RF received signal and an intermodulation distortion component associated therewith are included. A compensation signal is obtained, and this compensation signal is combined with the RF reception signal, and unnecessary wave components are removed prior to amplification (see FIG. 8 (b ′)). In response to this, the operation of the wireless signal receiving apparatus shifts to the state 1, and as shown in FIGS. 8 (c ′) to (d ′), the unnecessary wave is dominantly received regardless of the reception environment. The generation of the intermodulation distortion itself can be suppressed, and the signal including only the desired wave can be used for the processing of the demodulator 408.

  In the radio signal receiving apparatus shown in FIG. 7 as well, as in the second embodiment described above, for example, the cycle in which state 0 and state 1 are repeated and the sampling cycle in demodulator 408 have an appropriate relationship. By appropriately adjusting the time required for the generation process of the compensation signal so as to satisfy, it is possible to prevent the sensitivity suppression occurring in the state 0 from affecting the processing of the demodulator 408.

(Fifth embodiment)
FIG. 9 shows a fifth embodiment of a radio signal receiving apparatus according to the present invention. FIG. 10 is a diagram illustrating an operation for compensating for intermodulation distortion.
9 that are the same as those shown in FIGS. 1, 5, and 12 are denoted by the same reference numerals as those shown in FIGS. 1, 5, and 12, and description thereof is omitted. To do.

In the radio signal receiving apparatus shown in FIG. 9, the compensation signal generated by the compensation signal generation unit 210 is inverted and input to the adder 211 provided in the previous stage of the high frequency first stage low noise amplifier 201.
In this case, as shown in FIGS. 10A to 10D, the compensation signal generated based on the radio frequency signal of the sub system and the reception signal of the main system delayed by the delay line 217 are obtained. After the synthesis and removal of unnecessary wave components, they are subjected to amplification processing by the high-frequency first stage low noise amplifier 201, so that the occurrence of intermodulation distortion itself can be suppressed.

As described above, the radio signal receiving apparatus according to the present invention compensates for the intermodulation distortion component caused by an unnecessary wave having a received power larger than that of a desired wave, so that a general-purpose element that is commercially available at a low price can be used. By using this, it is possible to realize avoidance of reception sensitivity suppression of desired waves due to intermodulation distortion.
This makes it possible to provide a wireless signal receiving device that can reliably receive a desired wave at a low price even in an environment in which a large number of operators are confused and provide mobile communication services. This is extremely useful in the field of manufacturing mobile communication terminals for using mobile communication systems such as mobile phone services.

  In addition, in an environment where access points for network services using a wireless LAN are installed unplanned, and also on a user's personal computer connected to such an access point using a wireless LAN When a service that enables connection to a network service through ad hoc connection is used, a situation in which sensitivity suppression for a desired wave is likely to occur. is there.

It is a figure which shows 1st Embodiment of the radio signal receiver concerning this invention. It is a figure explaining the operation | movement which compensates intermodulation distortion. It is a figure which shows 2nd Embodiment of the radio signal receiving apparatus concerning this invention. It is a figure explaining the operation | movement which compensates intermodulation distortion. It is a figure which shows 3rd Embodiment of the radio signal receiving apparatus concerning this invention. It is a figure explaining the operation | movement which compensates intermodulation distortion. It is a figure which shows 4th Embodiment of the radio signal receiving apparatus concerning this invention. It is a figure explaining the operation | movement which compensates intermodulation distortion. It is a figure which shows 5th Embodiment of the radio signal receiving apparatus concerning this invention. It is a figure explaining the operation | movement which compensates intermodulation distortion. It is a figure explaining the environment where intermodulation distortion generate | occur | produces. It is a figure which shows the structural example of the conventional radio signal receiver.

Explanation of symbols

201, 218 High frequency first stage low noise amplifier 202 Band stop filter 203, 405 Intermediate frequency amplifier 204 Band pass filter 205 Variable attenuator 206 Error detection unit 207, 211 Adder 210 Compensation signal generation unit 212, 215, 219, 401 High frequency Amplifier 213, 220, 403 Multiplier 214, 221, 404 Filter 216 Divider 217 Delay line 218 High frequency first stage low noise amplifier 402 Local oscillator 407 Band pass filter 408 Demodulator

Claims (5)

A high frequency amplifier for amplifying the received radio frequency signal;
A frequency conversion circuit for converting the radio frequency signal into an appropriate intermediate frequency signal;
An intermediate frequency amplifier for amplifying the intermediate frequency signal obtained by the frequency conversion circuit;
A first band pass filter that passes a signal in a band including a frequency of a desired wave among the intermediate frequency signals output from the intermediate frequency amplifier;
A band rejection filter that selectively blocks signals in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and passes signals in other bands;
A pseudo distortion adding means for adding pseudo intermodulation distortion by amplifying the intermediate frequency signal that has passed through the band rejection filter;
A second band-pass filter for passing a signal in a band including a frequency of a desired wave among signals to which pseudo intermodulation distortion is added by the pseudo-distortion adding means;
A radio signal receiving apparatus comprising: a subtractor that subtracts the output signal of the second bandpass filter from the output signal of the intermediate frequency amplifier and uses the obtained signal for processing of a demodulator. A first stage high frequency amplifier for amplifying the received radio frequency signal;
Compensation signal generating means for generating a compensation signal for compensating for intermodulation distortion generated in the first-stage high-frequency amplifier;
A subtractor for subtracting the compensation signal from the output signal of the first stage high frequency amplifier;
A second stage high frequency amplifier for amplifying a radio frequency signal output from the subtractor;
A first frequency conversion circuit for converting an output signal of the second-stage high-frequency amplifier into a signal having an appropriate intermediate frequency;
An intermediate frequency amplifier for amplifying the intermediate frequency signal obtained by the frequency conversion circuit;
A band-pass filter that passes a signal in a band including a frequency of a desired wave among the intermediate-frequency signals output from the intermediate-frequency amplifier, and is provided for processing of a demodulator;
The compensation signal generating means includes
A band rejection filter that selectively blocks signals in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and passes signals in other bands;
A second frequency conversion circuit that generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting an intermediate frequency signal that has passed through the band rejection filter;
Pseudo-distortion generating means for amplifying the radio frequency signal obtained by the second frequency conversion circuit to generate the compensation signal including pseudo intermodulation distortion and inputting the compensation signal to the subtractor. A wireless signal receiving device. A distributor for branching the received radio frequency signal into two systems, a main system and a sub system;
A main-system first-stage high-frequency amplifier that amplifies the main-system radio frequency signal;
Compensation signal generating means for generating a compensation signal for compensating intermodulation distortion generated in the main system first stage high frequency amplifier;
A delay circuit disposed between the distributor and the main system first-stage high-frequency amplifier, and giving a delay corresponding to a time required for the compensation signal generation processing by the compensation signal generation means to the radio frequency signal of the main system;
A subtractor for subtracting the compensation signal from the output signal of the main system first-stage high-frequency amplifier;
A main system next-stage high-frequency amplifier that amplifies a radio frequency signal output from the subtractor;
A main system frequency conversion circuit for converting an output signal of the main system next-stage high-frequency amplifier into a signal having an appropriate intermediate frequency;
A main intermediate frequency amplifier that amplifies the intermediate frequency signal obtained by the main frequency conversion circuit;
A band-pass filter that passes a signal in a band including a frequency of a desired wave among intermediate-frequency signals output from the main-system intermediate-frequency amplifier, and is used for processing of a demodulator;
The compensation signal generating means includes
A sub-system first-stage high-frequency amplifier for amplifying the sub-system radio frequency signal;
A sub-system second-stage high-frequency amplifier that amplifies a radio frequency signal output from the sub-system first-stage high-frequency amplifier;
A first frequency conversion circuit for converting an output signal of the sub-system next-stage high-frequency amplifier into a signal having an appropriate intermediate frequency;
A sub-system intermediate frequency amplifier for amplifying the intermediate frequency signal obtained by the first frequency conversion circuit;
A band rejection filter that selectively blocks signals in a band including the frequency of the desired wave among intermediate frequency signals output from the sub-system intermediate frequency amplifier, and passes signals in other bands;
A second frequency conversion circuit that generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting an intermediate frequency signal that has passed through the band rejection filter;
Pseudo-distortion generating means for amplifying the radio frequency signal obtained by the second frequency conversion circuit to generate the compensation signal including pseudo intermodulation distortion and inputting the compensation signal to the subtractor. A wireless signal receiving device. A combiner that combines the received radio frequency signal and the compensation signal generated by the compensation signal generating means;
A high frequency amplifier for amplifying a radio frequency signal output from the combiner;
A first frequency conversion circuit for converting an output signal of the high-frequency amplifier into a signal having an appropriate intermediate frequency;
An intermediate frequency amplifier for amplifying the intermediate frequency signal obtained by the frequency conversion circuit;
A band-pass filter that passes a signal in a band including a frequency of a desired wave among the intermediate-frequency signals output from the intermediate-frequency amplifier, and is provided for processing of a demodulator;
The compensation signal generating means includes
A band rejection filter that selectively blocks signals in the band including the frequency of the desired wave among the intermediate frequency signals output from the intermediate frequency amplifier, and passes signals in other bands;
A second frequency conversion circuit that generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting an intermediate frequency signal that has passed through the band rejection filter;
Inverting input means for generating the compensation signal as a signal obtained by inverting the phase of the radio frequency signal based on the radio frequency signal obtained by the second frequency conversion circuit and inputting the compensation signal to the combiner; A radio signal receiving apparatus characterized by the above. A distributor for branching the received radio frequency signal into two systems, a main system and a sub system;
A synthesizer for synthesizing the main system radio frequency signal and the compensation signal generated by the compensation signal generating means;
A delay circuit disposed between the distributor and the combiner, and providing a delay corresponding to a time required for a compensation signal generation process by the compensation signal generation means to the main radio frequency signal;
A high frequency amplifier for amplifying a radio frequency signal output from the combiner;
A main frequency conversion circuit for converting an output signal of the high-frequency amplifier into a signal having an appropriate intermediate frequency;
A main intermediate frequency amplifier that amplifies the intermediate frequency signal obtained by the main frequency conversion circuit;
A band-pass filter that passes a signal in a band including a frequency of a desired wave among intermediate-frequency signals output from the main-system intermediate-frequency amplifier, and is used for processing of a demodulator;
The compensation signal generating means includes
A sub-system high-frequency amplifier for amplifying the sub-system radio frequency signal;
A first frequency conversion circuit for converting an output signal of the sub-system high-frequency amplifier into a signal having an appropriate intermediate frequency;
A sub-system intermediate frequency amplifier for amplifying the intermediate frequency signal obtained by the first frequency conversion circuit;
A band rejection filter that selectively blocks signals in a band including the frequency of the desired wave among intermediate frequency signals output from the sub-system intermediate frequency amplifier, and passes signals in other bands;
A second frequency conversion circuit that generates a radio frequency signal in a frequency band corresponding to the received radio frequency signal by frequency converting an intermediate frequency signal that has passed through the band rejection filter;
Inverting input means for generating the compensation signal as a signal obtained by inverting the phase of the radio frequency signal based on the radio frequency signal obtained by the second frequency conversion circuit and inputting the compensation signal to the combiner; A radio signal receiving apparatus characterized by the above.

Images