JP2006352321A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of enhancing the reception sensitivity by reducing a noise component generated by down-conversion. <P>SOLUTION: The receiver includes: a reception antenna 101 for receiving a high frequency signal at a millimeter wave band including a main carrier signal component and a side band signal component; a signal input section 110 for inputting the received millimeter wave reception signal A; an input power adjustment section 120 for adjusting the power of the input signal; a 2-branch unit 102 for branching a signal C output from the input power adjustment section 120 into two paths; a main carrier signal power adjustment section 130 that adjusts the power of the main carrier signal; a side band signal power adjustment section 140 that adjusts the power of the side wave band signal; a 2-branch unit 103 that branches an output signal D of the section 130 into two, i.e. a control circuit 104 and a signal output section 150; the control circuit 104 that outputs a control signal for adjusting the power of the signal C to the input power adjustment section 120; and the signal output section 150 that outputs a signal F with a base band frequency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a receiving apparatus that receives, for example, a millimeter-wave band radio signal.

  2. Description of the Related Art In recent years, research and development have been actively conducted on optical / wireless fusion technology in which, for example, millimeter-wave band high-frequency signals are transmitted through optical fibers, and photoelectric conversion is performed at a relay point of the optical fiber transmission path for wireless transmission. This technique is very useful as a means for supplementing optical fiber transmission when, for example, an existing apartment house where it is difficult to pull in an optical fiber cable for joint reception of broadcast waves or when a river crosses an optical fiber installation route.

  Assuming that optical and wireless fusion technology is applied to the reception of broadcast wave signals for terrestrial digital broadcasting, after modulating the carrier light obtained from the same light source with the broadcast wave signal and the unmodulated signal in the millimeter wave band, A method has been proposed in which wavelength-division multiplexing is used for optical transmission, and a broadcast wave signal is obtained by frequency conversion to a millimeter wave band by photoelectric conversion at a relay point (for example, see Non-Patent Document 1).

  However, since the millimeter wave band signal has an extremely large transmission loss as compared with a radio signal used in general wireless transmission, for example, a wireless LAN (Local Area Network), a receiving apparatus that further improves the reception sensitivity of the millimeter wave band signal is provided. There is a need for a method to configure. The configuration of the receiving device differs depending on the type of the main carrier signal of the received radio signal, and the main carrier signal will be described in detail below.

  As an amplitude modulation method of a main carrier signal in wireless transmission, a double sideband modulation method, a single sideband modulation method, and a residual sideband modulation method are generally used. Among them, the single sideband modulation method is a desirable modulation method particularly for wireless transmission of wideband signals because the occupied bandwidth is ½ or less of the double sideband modulation method.

  The single sideband modulation method can be further classified into the following three modulation methods according to the transmission method of the main carrier signal. That is, the single sideband modulation method is classified into an all-carrier method that transmits the main carrier signal as it is, a suppressed carrier method that does not transmit the main carrier signal, and a reduced carrier method that transmits the main carrier signal with reduced power. This will be described in detail below.

  First, the local carrier signal does not require a local oscillation signal on the receiving side, and the received high-frequency signal can be converted to a baseband frequency signal (hereinafter referred to as “down-conversion”) by square detection of a non-linear element, for example. Therefore, it has an advantage that the receiving apparatus can be configured simply, and is generally called a self-heterodyne system. In addition, in the all-carrier system, a stable signal can be obtained because the main carrier signal and the frequency fluctuations and phase noise of the sidebands are canceled during the down-conversion.

  However, since the full carrier scheme needs to transmit a sufficiently large main carrier signal as compared with the sideband signal, the ratio of the power of the sideband signal to the total transmission power is limited. If the ratio of the sideband signal power is small, there is a problem that the reception sensitivity is lowered due to thermal noise generated in the receiving apparatus, and the receivable range is narrowed. As a receiving apparatus using this all-carrier wave system, for example, the one disclosed in Patent Document 1 is known.

  Next, since the suppressed carrier scheme does not transmit the main carrier signal, it is advantageous in terms of the receivable range as compared with the all carrier scheme under the condition that the total transmission power is constant. However, since separate local oscillation signals are used on the transmission side and the reception side, the influence of frequency fluctuation and phase noise remains on the signal of the down-conversion output of the reception device. In order to solve this problem, the transmitter transmits a pilot signal having the same spectrum as that of the local oscillation signal on the transmission side to the frequency near the sideband signal and transmits the multiplexed signal. Based on the above, there has been proposed a technique for controlling the local oscillation signal on the receiving side to reduce the influence of frequency fluctuation (see, for example, Patent Document 2). However, in a very high frequency region such as the millimeter wave band, it is not easy to completely suppress frequency fluctuations and phase noise, and a complicated processing circuit is required for the receiving device, which greatly increases manufacturing costs. There's a problem.

  In addition, a method has been proposed in which a sideband signal and a main carrier signal are separated in advance on the transmitting side, both are transmitted with two orthogonal polarized waves, and received with a linearly polarized antenna arranged orthogonally on the receiving side. (For example, refer nonpatent literature 2.). This method is advantageous in terms of frequency fluctuations and phase noise, like the all-carrier method. However, since the deterioration of the cross-polarization identification characteristics of the receiving antenna leads to the deterioration of the signal quality of the down-conversion output, cross-polarization identification is possible. There is a problem that a receiving antenna having excellent characteristics is required and the manufacturing cost increases.

  Next, the reduced carrier scheme is a method that compensates for the shortcomings of the all-carrier scheme and the suppressed carrier scheme. By reducing the power of the main carrier signal, the ratio of the sideband signal to the total transmission power can be increased as compared with the case of the full carrier system, and the reception sensitivity can be improved. In the reduced carrier scheme, a stable signal that is not affected by frequency fluctuations or phase noise can be obtained by using the transmitted main carrier signal for down conversion.

  As described above, in the amplitude modulation method of the main carrier signal in wireless transmission, the single sideband modulation method includes three types of modulation methods, an all-carrier method, a suppressed carrier method, and a reduced carrier method. It can be said that the use of the method is preferable for a receiving apparatus that receives a millimeter-wave band signal with extremely large transmission loss.

Kenji Suzuki, et al. “Millimeter-wave optical fiber transmission experiment of digital terrestrial broadcasting”, Technical Report of the Institute of Image Information and Television Engineers, Vol. 27, no. 45, PP. 1-6, BCT2003-13 (Jul. 2003) Yozo Soji, et al., "A Study on Millimeter-wave Communication System Using Self-Heterodyne Detection", 1999 IEICE Society Conference, PP. 370, B-5-135 (Sept. 1999) JP 2003-198259 A JP 2004-235758 A

  However, in the conventional receiver using the reduced carrier scheme, if the main carrier signal is made sufficiently lower than the sideband signal in order to improve the reception sensitivity, the noise component in the general self-heterodyne downconversion Occurs, and the signal quality is degraded.

  The present invention has been made to solve the conventional problems, and provides a receiving apparatus capable of reducing the noise component generated by down-conversion and improving the receiving sensitivity.

  The receiving apparatus of the present invention includes a radio signal receiving unit that receives a radio signal including a main carrier signal component and a sideband signal component, a main carrier signal extraction unit that extracts the main carrier signal component from the radio signal, And a sideband signal extracting means for extracting the sideband signal component from the radio signal.

  With this configuration, the receiving device of the present invention can separately adjust the powers of the main carrier signal component and the sideband signal component, so that the sideband signal component and the main carrier component are before the down conversion. And the noise component included in the main carrier component can be reduced, and the noise component generated by the down-conversion can be reduced to improve the reception sensitivity.

  Further, the receiving device of the present invention uses the frequency of the sideband signal component extracted by the sideband signal extraction unit based on the main carrier signal component extracted by the main carrier signal extraction unit as a baseband frequency. It has the structure provided with the frequency conversion means to convert into.

  With this configuration, the receiving apparatus of the present invention does not require a local oscillator that generates a local oscillation signal for performing down conversion, so that the manufacturing cost can be reduced as compared with the conventional one.

  Furthermore, the receiving apparatus of the present invention has a configuration including a noise component suppressing unit that suppresses the noise component, wherein the main carrier signal component extracted by the main carrier signal extracting unit includes a noise component. .

  With this configuration, since the noise component suppressing unit suppresses the noise component included in the main carrier signal component, the receiving apparatus of the present invention can perform down conversion using the main carrier signal component in which the noise component is suppressed. In addition, it is possible to improve the reception sensitivity by reducing the noise component generated by the down conversion.

  Furthermore, the receiving apparatus of the present invention has a configuration including intermediate frequency conversion means for converting the frequency of the radio signal to a frequency between the frequency of the radio signal and the baseband frequency.

  With this configuration, in the receiving apparatus of the present invention, the noise component suppressing unit can suppress the noise component included in the main carrier signal component in the frequency band smaller than the radio frequency, and thus suppress the noise component in the radio frequency band. Therefore, the structure of the noise component suppressing means can be simplified and the manufacturing cost can be reduced.

  Furthermore, the receiving apparatus of the present invention includes a main carrier signal power adjusting unit that adjusts the power of the main carrier signal component extracted by the main carrier signal extracting unit, and the side extracted by the sideband signal extracting unit. And a sideband signal power adjusting means for adjusting the power of the waveband signal component.

  With this configuration, the main carrier signal power adjusting unit and the sideband signal power adjusting unit separately adjust the power of the main carrier signal component and the sideband signal component, respectively. Before performing the transmission, the power ratio between the sideband signal component and the main carrier component can be made sufficiently large to reduce the noise component contained in the main carrier component, and the noise component generated by downconversion can be reduced and received. The sensitivity can be improved.

  Also, with this configuration, the receiving apparatus of the present invention can separately adjust the power of the main carrier signal component and the sideband signal component, so that the dynamic range of the received signal can be expanded.

  Furthermore, the receiving apparatus of the present invention has a configuration including main carrier signal power setting means for setting the power of the signal output from the main carrier signal power adjustment means within a predetermined range.

  With this configuration, the receiving device of the present invention can stabilize the power of the signal output from the main carrier signal power adjusting means even when receiving a high-frequency signal such as a millimeter wave whose power is difficult to stabilize. The sideband signal component can be down-converted using the main carrier signal component whose power is stabilized.

  Furthermore, the receiving apparatus of the present invention has a configuration provided with sideband signal power setting means for setting the power of the signal output from the sideband signal power adjustment means within a predetermined range.

  With this configuration, the receiving apparatus of the present invention can stabilize the power of the signal output from the sideband signal power adjusting means, so that the fluctuation of the power ratio between the sideband signal component and the main carrier signal component Can be kept within a predetermined range, and noise components generated by down-conversion can be reduced to improve reception sensitivity.

  The present invention can provide a receiving apparatus having an effect of reducing the noise component generated by down conversion and improving the receiving sensitivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An example in which the receiving apparatus of the present invention receives a millimeter-wave band high-frequency signal will be described.

(First embodiment)
First, the configuration of the receiving apparatus according to the first embodiment of the present invention will be described.

  As shown in FIG. 1, a receiving apparatus 100 according to the present embodiment includes a receiving antenna 101 that receives a millimeter-wave band high-frequency signal including a main carrier signal component and a sideband signal component, and a millimeter that is received by the receiving antenna 101. A signal input unit 110 that inputs the received wave signal A, an input power adjustment unit 120 that adjusts the power of the input signal, a two-branch unit 102 that branches the signal C output from the input power adjustment unit 120 into two paths, , A main carrier signal power adjusting unit 130 for adjusting the power of the main carrier signal, and a sideband signal power adjusting unit 140 for adjusting the power of the sideband signal. The receiving antenna 101 constitutes a radio signal receiving means of the present invention.

  The receiving apparatus 100 according to the present embodiment also includes a two-branch unit 103 that branches the signal D output from the main carrier signal power adjustment unit 130 into a control circuit 104 and a signal output unit 150, and a signal C A control circuit 104 that outputs a control signal for adjusting power to the input power adjustment unit 120, and signals D and E output from the main carrier signal power adjustment unit 130 and the sideband signal power adjustment unit 140, respectively, are input. And a signal output unit 150 that outputs a signal F having a baseband frequency.

  The signal input unit 110 includes a millimeter wave amplifier 111 that amplifies the millimeter wave reception signal A received by the receiving antenna 101, a band pass filter 112 that filters a signal in a predetermined frequency band, and a millimeter wave sine wave as a local oscillation signal. Millimeter-wave local oscillator 113 that generates signal B, millimeter-wave amplifier 114 that amplifies millimeter-wave sine wave signal B, millimeter-wave reception signal A that is filtered by bandpass filter 112, and millimeter-wave that is amplified by millimeter-wave amplifier 114 A mixer 115 that multiplies the sine wave signal B to generate signals of two different frequencies, and a low-pass filter 116 that filters a low-frequency signal among the signals generated by the mixer 115 are provided. The millimeter wave local oscillator 113 constitutes the intermediate frequency conversion means of the present invention.

  The input power adjustment unit 120 includes an amplifier 121 that amplifies the output signal of the low-pass filter 116 and a variable attenuator 122 having a feedback control function, and outputs the signal C to the two-branch unit 102. . Note that the variable attenuator 122 operates based on a control signal from the control circuit 104.

  The main carrier signal power adjustment unit 130 receives one of the signals branched by the two-branch unit 102, filters this signal, and extracts an unmodulated sine wave signal that is the main carrier signal; An amplifier 132 that amplifies the unmodulated sine wave signal extracted by the band pass filter 131, and a narrow band pass filter 133 that further suppresses noise components included in the unmodulated sine wave signal in a band narrower than the band of the band pass filter 131. And an amplifier 134 that amplifies the unmodulated sine wave signal extracted by the narrow band pass filter 133, and outputs the signal D to the two-branch unit 103.

  The main carrier signal power adjustment unit 130 constitutes a main carrier signal power adjustment unit of the present invention. Further, the band pass filter 131 constitutes a main carrier signal extraction means of the present invention. The narrow band pass filter 133 constitutes a noise component suppressing unit of the present invention.

  The control circuit 104 monitors the power level of the signal D output from the main carrier signal power adjustment unit 130 and controls the attenuation amount of the variable attenuator 122 so that the power level of the signal D is within a preset range. The control signal for output is output to the variable attenuator 122. The control circuit 104 and the variable attenuator 122 constitute main carrier signal power setting means of the present invention.

  The sideband signal power adjustment unit 140 receives the other signal branched by the two-branch unit 102, filters the signal, and extracts a sideband signal, and a bandpass filter 141. And an amplifier 142 that amplifies the extracted sideband signal, and outputs a signal E to the signal output unit 150.

  The sideband signal power adjustment unit 140 constitutes a sideband signal power adjustment unit of the present invention. The band pass filter 141 constitutes the sideband signal extraction means of the present invention.

  The signal output unit 150 multiplies the signal D and the signal E, generates a signal having two different frequencies, and a low-pass filter 152 that filters a low-frequency signal among the signals generated by the mixer 151. And an amplifier 153 that amplifies the signal filtered by the low-pass filter 152, downconverts the signal E using the signal D, and outputs a signal F in the baseband frequency band. . The power level of the signal D input to the mixer 151 is amplified by the amplifier 132 and the amplifier 134 to a power level at which the mixer 151 operates properly. The mixer 151 constitutes the frequency conversion means of the present invention.

  Next, the operation of receiving apparatus 100 of the present embodiment will be described.

First, a high frequency signal in the millimeter wave band is received by the receiving antenna 101, and the received millimeter wave received signal A is output to the signal input unit 110. Here, when the baseband frequency is expressed as f _sig and the frequency of the main carrier signal of the millimeter wave reception signal A received by the receiving antenna 101 is expressed as f _car , the frequency of the sideband signal included in the millimeter wave reception signal A Is represented as f _car + f _sig .

Next, the millimeter wave reception signal A input to the signal input unit 110 is amplified by the millimeter wave amplifier 111, and then the out-of-band signal is suppressed by the band pass filter 112. On the other hand, an unmodulated millimeter wave sine wave signal B having an oscillation frequency f _loc is output from the millimeter wave local oscillator 113 and amplified by the millimeter wave amplifier 114.

  Further, the millimeter wave reception signal A and the millimeter wave sine wave signal B are converted by the mixer 115 into signals of the frequency of the sum and difference. Then, only the low-frequency signal is filtered by the low-pass filter 116 and output to the input power adjusting unit 120.

Subsequently, the signal input to the input power adjustment unit 120 is adjusted to a predetermined value by the amplifier 121 and the variable attenuator 122 having a feedback control function, and is output to the two-branch unit 102. Here, when the signal outputted from the input power adjusting unit 120 and the signal C, signal C is an intermediate frequency _f car and unmodulated signal _{-f loc,} likewise intermediate frequency _f car _{+ f} sig _{-f loc} sideband signal It consists of.

  Next, the signal C is branched into two paths by the two-branch unit 102, and one is output to the main carrier signal power adjustment unit 130 and the other is output to the sideband signal power adjustment unit 140.

  One signal C branched by the two-branch unit 102 is processed in the main carrier signal power adjustment unit 130 as follows.

  First, only the unmodulated sine wave signal, which is the main carrier signal, is selected by the band pass filter 131 and amplified by the amplifier 132.

  Next, the out-of-band thermal noise component included in the unmodulated sine wave signal is further suppressed by the narrow band pass filter 133 and then amplified by the amplifier 134. The amplifier 132 and the amplifier 134 amplify the power level of the unmodulated sine wave signal to a power level at which the mixer 151 operates appropriately, and the signal D is output from the amplifier 134 to the bifurcater 103.

Here, the signal D is an unmodulated sine wave signal having a frequency f _car -f _loc . This unmodulated sine wave signal is used as a frequency conversion signal in the mixer 151 of the signal output unit 150 as will be described later. However, since the thermal noise component can be suppressed by using the narrow band pass filter 133, the present embodiment The receiving apparatus 100 according to the embodiment can prevent signal quality from being deteriorated due to a thermal noise component.

  Subsequently, a signal D including an unmodulated sine wave signal is branched into two paths by the two-branch unit 103, and one is output to the control circuit 104 and the other is output to the mixer 151.

  Next, the control circuit 104 monitors the power level of the signal D, and controls the amount of attenuation of the variable attenuator 122 so that the power level of the signal D is within a preset range.

The other signal C branched by the two-branch unit 102 is first filtered by the band-pass filter 141 in the sideband signal power adjustment unit 140, and a sideband signal is extracted from the signal C. The frequency of this sideband signal is f _car + f _sig −f _loc .

  Next, after the sideband signal is amplified by the amplifier 142, it is output to the mixer 151 as the signal E.

  Subsequently, the mixer 151 converts the signal D and the signal E into signals having the frequency of the sum and difference. Then, only the low-frequency side signal is filtered by the low-pass filter 152, then amplified by the amplifier 153, and the baseband frequency signal F is output.

In the above description, it is assumed that the millimeter wave local oscillator 113 oscillates ideally and the frequency f _loc of the output millimeter wave sine wave signal B is stable. However, the actual oscillator comprises a fluctuation frequency Delta] f _l according to influence of frequency variation and phase noise component. At this time, the oscillation frequency of the millimeter wave local oscillator 113 becomes _{f loc} + _{Δf l.} In receiving apparatus 100 according to the present embodiment, since f _loc + Δf ₁ is canceled in principle in mixer 151, signal F having a stable f _sig frequency is obtained without being affected by fluctuation frequency Δf _l. Can do. Further, when the frequency f _car of the main carrier signal has a fluctuation frequency Delta] f _c in the transmission side, it is offset by the mixer 151 in the same manner as described above.

  Therefore, receiving apparatus 100 according to the present embodiment can cancel all frequency fluctuations and phase noise components generated by an oscillator that generates a signal having a frequency in the millimeter wave band including the transmission apparatus. It is possible to obtain a high-quality signal having a stable frequency without being affected by the phase noise component or the like.

Furthermore, in receiving apparatus 100 according to the present embodiment, main carrier signal power adjustment section 130 and sideband signal power adjustment section 140 are separated, and are configured to independently adjust power. Even when the main carrier signal having the frequency f _car of the wave reception signal A is smaller than the sideband signal, downconversion can be performed without causing distortion in the mixer 151.

  Next, the influence of the power ratio between the sideband signal and the main carrier signal and the passband width of the narrow band pass filter 133 on the carrier to noise ratio (hereinafter referred to as “CNR”). The effectiveness of the narrow band pass filter 133 in the receiving apparatus 100 according to the present embodiment is shown.

In general, when the CNR of an input signal for a device having a noise figure F _i is CNR _IN and the CNR of the output signal is CNR _OUT , CNR _OUT is expressed by Expression (1).

Here, k is the Boltzmann constant, T is the absolute temperature, B _i is the signal bandwidth, and _PIN is the input signal power.

Next, the pass band width of the narrow band pass filter 133 is 2B _g , the power of the main carrier signal of the signal D is P _L , the CNR is CNR _L , and the noise power per 1 Hz near the main carrier signal is n _L. On the other hand, the power of the sideband signal of the signal E is P _S , the CNR is CNR _S , and the noise power per 1 Hz is n _S. However, the definition of the noise bandwidth of CNR _L and CNR _{S is} the sideband signal bandwidth B ₀ . At this time, if the CNR of the output signal frequency-converted by the mixer 151 is CNR _IF , the CNR _IF is expressed by Expression (2).

Since B _g is smaller than B ₀ , CNR _IF ⁻¹ can be approximated as shown in Equation (3).

In the main carrier signal power adjustment unit 130 and the sideband signal power adjustment unit 140 shown in FIG. 1, the input power is P _{in, L} and P _{in, S} , and the input CNR is CNR _{in, L} and CNR _{in, respectively. S,} the noise figure and _{F L} and _{F S.} Since CNR _L and CNR _S are output CNRs of the main carrier signal power adjustment unit 130 and the sideband signal power adjustment unit 140, respectively, they can be expressed as Equation (4) using Equation (1).

Here, when the power ratios P _{in, S} / P _{in, L} between the sideband signal component and the main carrier signal component included in the signal C are γ, the noise power of the sideband signal component and the main carrier signal component is Since they are the same, the following equation is obtained.

When F _S = F _L = F, Expression (6) is obtained.

In Expression (6), when the input power is sufficiently large and the second term in [] is ignored, calculation of γ vs. CNR _IF when a main carrier signal having a CNR _{in, L} of, for example, 30 dB is input to the receiving apparatus. The values are shown in FIG. 2 with 2B _g / B ₀ as a parameter.

As shown in FIG. 2, an area larger than the power of the power of the sideband signal is a main carrier signal, that is, if the reduction carrier scheme, the more narrow the filter width B _g of the narrow band pass filter 133, the output signal It can be seen that the CNR of can be improved.

  The frequency is converted by the millimeter wave local oscillator 113 because the frequency of the millimeter wave reception signal A received by the receiving antenna 101 is changed to a frequency between the frequency of the millimeter wave reception signal A and the baseband frequency of the signal F. This is because the narrow bandpass filter 133 having a narrow passband width can be easily manufactured by lowering the value.

  As described above, according to receiving apparatus 100 of the present embodiment, main carrier signal power adjustment section 130 and sideband signal power adjustment section 140 separately adjust the power of the main carrier signal and the sideband signal. Therefore, before down-conversion, the power ratio between the sideband signal and the main carrier signal can be increased sufficiently to reduce the noise component contained in the main carrier signal. Therefore, it is possible to improve the reception sensitivity by reducing the noise component generated by.

  Further, according to receiving apparatus 100 of the present embodiment, mixer 151 is configured to down-convert the sideband signal using the unmodulated sine wave signal that is the main carrier signal, so that the down-conversion is performed. A local oscillator for generating a local oscillation signal is not required, and the manufacturing cost can be reduced as compared with the conventional one.

  Furthermore, according to receiving apparatus 100 of the present embodiment, narrowband pass filter 133 is configured to suppress the noise component contained in the main carrier signal, and therefore down-converted using the main carrier signal in which the noise component is suppressed. Conversion can be performed, and noise components generated by down conversion can be reduced to improve reception sensitivity.

  Furthermore, according to receiving apparatus 100 of the present embodiment, millimeter wave local oscillator 113 generates an intermediate frequency signal for converting the frequency of the radio signal to a frequency between the frequency of the radio signal and the baseband frequency. Therefore, the structure of the narrow band pass filter 133 can be simplified and the manufacturing cost can be reduced as compared with the case of suppressing the noise component in the radio frequency band.

  Furthermore, according to the receiving apparatus 100 of the present embodiment, the millimeter wave local oscillator 113 is configured to generate the above-described intermediate frequency signal, and therefore has a narrower band than that which suppresses noise components in the radio frequency band. The noise bandwidth can be suppressed with high accuracy by narrowing the pass bandwidth of the pass filter 133, and the reception sensitivity can be improved by reducing the noise component generated by the down conversion.

  Furthermore, according to receiving apparatus 100 of the present embodiment, the power of the main carrier signal and the sideband signal can be adjusted separately, so that the dynamic range of the received signal can be expanded.

  Furthermore, according to receiving apparatus 100 of the present embodiment, control circuit 104 and variable attenuator 122 set the power of signal D output from main carrier signal power adjustment section 130 within a predetermined range by feedback control. Since it is configured, even when receiving a high-frequency signal such as a millimeter wave whose power is difficult to stabilize, the power of the signal D output from the main carrier signal power adjustment unit 130 can be stabilized, and the power is stable. The sideband signal can be down-converted using the converted main carrier signal.

  In the above-described embodiment, the configuration for receiving a millimeter-wave band high-frequency signal has been described as an example. However, the present invention is not limited to this, and a high-frequency signal whose frequency is likely to fluctuate is received. If it is a thing, the same effect is acquired.

  In the above-described embodiment, the main carrier signal power adjustment unit 130 has been described by taking as an example a configuration having two filters, the band pass filter 131 and the narrow band pass filter 133, but the present invention is not limited thereto. If the desired noise level can be obtained, the same effect can be obtained even if it is composed of one filter.

(Second Embodiment)
First, the configuration of the receiving apparatus according to the second embodiment of the present invention will be described.

  As shown in FIG. 3, the receiving apparatus 200 of the present embodiment includes a receiving antenna 201 that receives a millimeter-wave band high-frequency signal including a main carrier signal component and a sideband signal component, and a millimeter that is received by the receiving antenna 201. A signal input unit 210 that receives the received wave signal A, an input power adjustment unit 220 that adjusts the power of the input signal, and a two-branch unit 202 that branches the signal C output from the input power adjustment unit 220 into two paths. A main carrier signal power adjusting unit 230 that adjusts the power of the main carrier signal, and a sideband signal power adjusting unit 240 that adjusts the power of the sideband signal. The receiving antenna 201 constitutes a radio signal receiving means of the present invention.

  The receiving apparatus 200 according to the present embodiment also includes a two-branch unit 203 that branches the signal D output from the main carrier signal power adjustment unit 230 into a control circuit 204 and a signal output unit 250, and a signal C A control circuit 204 that outputs a control signal for adjusting power to the input power adjustment unit 220, and signals D and E output from the main carrier signal power adjustment unit 230 and the sideband signal power adjustment unit 240, respectively, are input. A signal output unit 250 that outputs a signal F of a baseband frequency, and a control circuit 206 that outputs a control signal for monitoring the power of the signal F and adjusting the power level of the signal E to the input power adjustment unit 240. I have.

  Note that the configuration of receiving apparatus 200 according to the present embodiment is obtained by changing a part of the configuration of receiving apparatus 100 according to the first embodiment of the present invention. Only the description of the configuration similar to that of the receiving apparatus 100 will be omitted.

  The sideband signal power adjustment unit 240 receives the signal branched by the bifurcater 202, filters the signal to extract a sideband signal, and filters the bandpass filter 241. And a variable attenuator 243 having a feedback control function, and an amplifier 244 that amplifies the signal attenuated by the variable attenuator 243, and the signal E is sent to the signal output unit 250. It is designed to output.

  The sideband signal power adjustment unit 240 constitutes sideband signal power adjustment means of the present invention. Further, the band pass filter 241 constitutes a sideband signal extracting means of the present invention.

  The control circuit 206 monitors the power level of the signal F output from the signal output unit 250 via the two-branch unit 205, and attenuates the variable attenuator 243 so that the power level of the signal F is within a preset range. A control signal for controlling the amount is output to the variable attenuator 243. In other words, the control circuit 206 controls the amount of attenuation of the variable attenuator 243 based on the power level of the signal F so that the power level of the signal E is within a preset range. The control circuit 206 and the variable attenuator 243 constitute sideband signal power setting means of the present invention.

  Therefore, even if the power ratio γ between the sideband signal component and the main carrier signal component included in the signal F increases for some reason, for example, the increase amount of the signal F is variable by the control circuit 206 and the variable attenuator 243. The attenuator 243 is negatively fed back and operates so as to suppress the occurrence of distortion in the mixer 251. The control circuit 206 and the variable attenuator 243 constitute sideband signal power setting means of the present invention.

  Next, the operation of receiving apparatus 200 according to the present embodiment will be described. Only operations different from those of the receiving apparatus 100 according to the first embodiment of the present invention will be described below.

  The signal F output by the signal output unit 250 is branched into two paths by the two-branch unit 205, one being output to the control circuit 206 and the other being output as the output signal of the receiving device 200.

  Next, the control circuit 206 monitors the power level of the signal F, and controls the amount of attenuation of the variable attenuator 243 so that the power level of the signal F falls within a preset range.

  Then, after the sideband signal is amplified by the amplifier 244, the signal E is output to the mixer 251.

  In the receiving apparatus 100 (see FIG. 1) according to the first embodiment of the present invention, the power ratio γ between the sideband signal component and the main carrier signal component in the millimeter wave received signal A is always constant. However, in the receiving apparatus 200 according to the present embodiment, the control circuit 206 is configured to control the attenuation amount of the variable attenuator 243 as described above. Even when the power ratio γ with the carrier signal component increases, for example, the increase in the signal F is negatively fed back to the variable attenuator 243, so that the occurrence of distortion in the mixer 251 can be suppressed.

  As described above, according to the receiving apparatus 200 of the present embodiment, the control circuit 206 monitors the power level of the signal F, and the variable attenuator 243 so that the power level of the signal F falls within a preset range. A control signal for controlling the amount of attenuation is output to the variable attenuator 243, and the variable attenuator 243 performs feedback control on the power of the signal E output from the sideband signal power adjustment unit 240 in accordance with the control signal. Because the configuration is set within a predetermined range, even when receiving high-frequency signals such as millimeter waves where it is difficult to stabilize power, fluctuations in the power ratio γ between the sideband signal component and the main carrier signal component are predetermined. It is possible to reduce the noise component generated by down-conversion and improve the reception sensitivity.

The block diagram of the receiver which concerns on the 1st Embodiment of this invention The figure which shows the characteristic of (gamma) versus CNR _IF at the time of changing the pass-band width of a narrow-band pass filter in the receiver which concerns on the 1st Embodiment of this invention. The block diagram of the receiver which concerns on the 2nd Embodiment of this invention

Explanation of symbols

100, 200 Receiving device 101, 201 Receiving antenna (radio signal receiving means)
102, 103, 202, 203, 205 Two-branch unit 104, 204 Control circuit (main carrier signal power setting means)
206 Control circuit (sideband signal power setting means)
110, 210 Signal input unit 111, 114 Millimeter wave amplifier 112 Band pass filter 131 Band pass filter (main carrier signal extraction means)
141, 241 Band-pass filter (sideband signal extraction means)
113 millimeter wave local oscillator (intermediate frequency conversion means)
115 Mixer 116, 152 Low-pass filter 120, 220 Input power adjustment unit 121, 132, 134, 142, 153, 242, 244 Amplifier 122 Variable attenuator (main carrier signal power setting means)
243 Variable attenuator (sideband signal power setting means)
130, 230 Main carrier signal power adjustment unit (main carrier signal power adjustment means)
133 Narrow band pass filter (noise component suppression means)
140, 240 Sideband signal power adjustment section (sideband signal power adjustment means)
150, 250 Signal output unit 151, 251 Mixer (frequency conversion means)

Claims (7)

Radio signal receiving means for receiving a radio signal including a main carrier signal component and a sideband signal component, main carrier signal extraction means for extracting the main carrier signal component from the radio signal, and the sideband from the radio signal A receiving apparatus comprising a sideband signal extracting means for extracting a signal component. Frequency conversion means for converting the frequency of the sideband signal component extracted by the sideband signal extraction means to a baseband frequency based on the main carrier signal component extracted by the main carrier signal extraction means The receiving apparatus according to claim 1. 3. The main carrier signal component extracted by the main carrier signal extraction unit includes a noise component, and noise component suppression unit that suppresses the noise component is provided. Receiver device. 4. The receiving apparatus according to claim 2, further comprising intermediate frequency conversion means for converting the frequency of the radio signal to a frequency between the frequency of the radio signal and the baseband frequency. A main carrier signal power adjusting unit for adjusting the power of the main carrier signal component extracted by the main carrier signal extracting unit, and a power of the sideband signal component extracted by the sideband signal extracting unit. 5. The receiving apparatus according to claim 1, further comprising a sideband signal power adjusting unit. 6. The receiving apparatus according to claim 5, further comprising main carrier signal power setting means for setting the power of the signal output from the main carrier signal power adjusting means within a predetermined range. The receiving apparatus according to claim 5 or 6, further comprising sideband signal power setting means for setting the power of the signal output from the sideband signal power adjustment means within a predetermined range. .

Images