JP2003124823A - System and method for removing interfering wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a receiving circuit into an LSI (large-scale integration) and small-sized by relaxing the filter property of a receiving circuit in an interfering wave removal operation in which sampling is performed while my a phase shift of an interfering wave signal is changed to lower an interfering wave signal level and thereby to keep a desired signal level. SOLUTION: A system for removing an interfering wave has an interfering wave removal part 20 constituted of a phase shifter 21 which varies only the phase shift of the interfering wave signal to a receive signal, a sampling circuit 22 which samples the receive signal, a sampling circuit 23 which samples the phase-shifted interfering wave signal at a zero-crossing point, an adder 24 which performs composition so that the sampling signal is continuous, and a control part 11, and is equipped with a means using the control part 11 for controlling the voltage gain of a receiving circuit and the operation of the interfering wave removal part on the basis of a carrier wave level, a demodulated signal level and a demodulated data error rate as a criterion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver interference wave canceling circuit system and method constituting a wireless communication device.

[0002]

2. Description of the Related Art As a conventional interfering wave removing circuit system, there is a super-heterodyne receiving circuit system in which a narrow bandpass filter (BPF) can be easily formed and receiving sensitivity can be improved. It is removed by utilizing the filter characteristics in the lowered intermediate frequency band. As a conventional example, Japanese Patent Laid-Open No. 8-340268
A conventional example described in "receiver" will be described as an example.

The interference wave removing operation of the conventional radio receiver will be described below. FIG. 11 shows a conventional single converter.
1 illustrates a configuration of a John system receiver circuit.

In FIG. 11, 1 is an antenna, 2 is a bandpass filter (BPF) for selecting a received signal, 3 is a low noise amplifier for amplifying the received signal, and 4 is a mixture for converting the received signal into an intermediate frequency (IF). 5, 5 is a local oscillator used for frequency conversion, 6 is an intermediate frequency filter that removes interference waves and limits the band, 7 is a variable gain amplifier whose gain is variable with a control signal, and 8 is I, Q data from the intermediate frequency signal. A demodulator for generating a data signal, 9 is a level detector for detecting a signal level from I and Q data signals, and 10 is a filter for extracting a control voltage from the output of the level detector 9.

The operation of the receiving circuit configured as described above will be described below. First, antenna 1
After passing through the BPF 2, the received signal from is amplified by the low noise amplifier 3 and input to the mixer 4. In the mixer 4, the received signal is converted into an intermediate frequency signal by the signal of the predetermined frequency supplied from the local oscillator 5. The intermediate frequency signal passes through the intermediate frequency filter 6 and then the variable gain amplifier 7
Entered in. In addition, the variable gain amplifier 7 in the intermediate frequency band
The signal passed through is demodulated in the demodulator 8 into I and Q data signals.

Next, the I and Q data signals are input to the level detector 9 and subjected to operations such as the sum of squares to obtain a detection signal corresponding to the received electric field strength. The detection signal has a high-frequency unnecessary component removed by the filter 10, becomes a control voltage for controlling the gain of the variable gain amplifier 7, and is controlled so that the input level to the demodulator 8 becomes constant.

[0007]

However, in the above configuration, the interfering wave becomes higher than the reception level of the desired wave due to various conditions such as the near-far problem of the radio and the radio wave propagation, and the out-of-band of the intermediate frequency filter for band limiting. If the amount of attenuation is insufficient, the reception / demodulation operation will be hindered. That is, an interference wave outside the reception band can be removed by the top BPF, but an adjacent channel interference wave within the band can be interfered even with the output of the intermediate frequency filter unless the out-of-band attenuation of the intermediate frequency filter is sufficient. The level of the wave becomes higher than the level of the desired wave, the intermediate frequency level detector operates due to the interfering wave, and the level of the desired wave becomes low, which interferes with the demodulation operation.

Therefore, in order to avoid such a situation,
An intermediate frequency filter that removes interference waves such as adjacent channel interference waves must have a steep out-of-band attenuation, and as a result, the intermediate frequency filter becomes expensive and the intermediate frequency is generally Since the frequency is low and the shape of the intermediate frequency filter is large, the size of the receiving circuit is reduced, and the LSI (Large-Scale Integral)
realization becomes difficult.

As a means for ensuring the amount of out-of-band attenuation, a double super heterodyne system has been adopted in which a receiving circuit suppresses an interfering wave by a two-stage intermediate frequency filter. With this configuration, the interference wave can be sufficiently removed, but the circuit becomes complicated, and there is a problem that the power consumption increases as the circuit scale increases.

When the interfering wave signal level is extremely large and is adjacent to the desired signal, even if the receiving circuit is of the double super heterodyne system, the nonlinearity of the high frequency circuit, especially the dynamic range of the mixer If is not sufficient, an interfering component is generated in the band due to the intermodulation and the demodulation characteristic is deteriorated. To solve this problem, regardless of the single or double super heterodyne system, it is essential to expand the dynamic range of the mixer, resulting in an increase in current consumption.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an interfering wave removing system which can be downsized. Moreover, it aims at providing an inexpensive interference wave removal system. Another object of the present invention is to provide a high performance interference wave elimination method.

[0012]

SUMMARY OF THE INVENTION An interference wave removing system according to the present invention receives a received signal, generates a plurality of signals having different phases from the input received signal, samples each of the plurality of signals, and It is characterized by comprising an interference wave removing section for generating a combined signal obtained by combining the sampled signals of.

The interference wave removing method is further characterized by further comprising a filter for inputting the combined signal from the interference wave removing section, removing unnecessary components from the combined signal, and outputting the result.

The interference wave removing method further uses the degree of shifting the phase of the received signal, the timing of sampling, or the sampling width to reduce a specific frequency component from the received signal. It is characterized by comprising a control unit for controlling the interference wave removing unit.

The control unit controls the characteristics of the filter in correspondence with the interference wave removing unit.

The control unit controls sampling timing based on one of the zero-cross point of the received signal and a point with the zero-cross point as a reference, and the signals sampled from each of the plurality of signals are continuous. Thus, the phase of the received signal and the sampling width are controlled.

The interference wave removing section inputs the received signal,
The first sampling circuit for sampling the input received signal, the received signal is input, the phase shifter that shifts the phase of the received signal, and the signal whose phase shifter shifts the phase is input, and the input signal is input. A second sampling circuit for sampling, and an adder for inputting signals from the first sampling circuit and the second sampling circuit and for synthesizing a plurality of input signals to generate a synthetic signal. Characterize.

The interfering wave removing method further includes a switch for switching and outputting the received signal and the combined signal output from the interfering wave removing section, and the control section based on the quality of the received signal. Then, the switch is changed over.

The interfering wave removing method is provided in a receiving device which receives a signal and converts the signal into an intermediate frequency band signal, and the interfering wave removing section inputs the converted intermediate frequency band signal. It is characterized by doing.

The interfering wave removing method is provided in a receiving device for receiving the received signal and converting the receiving signal into a signal of a different frequency band, and the interfering wave removing method includes at least two interfering wave removing sections. One interfering wave removing section is characterized in that the signal before conversion is input as a received signal, and the other interfering wave removing section inputs the converted signal as a received signal.

The above-mentioned interfering wave removing system further comprises a variable gain amplifier for adjusting the signal level, and the above interfering wave removing system comprises a plurality of combinations of the interfering wave removing section, the filter and the variable gain amplifier. It is characterized in that the plurality of combinations are arranged in series.

The above-mentioned interference wave removing method is characterized in that it comprises a plurality of interference wave removing sections, and the plurality of interference wave removing sections are arranged in parallel.

According to the method for removing an interference wave according to the present invention, a received signal is input, a plurality of signals having different phases are generated from the input received signal, each of the plurality of signals is sampled, and the plurality of sampled signals are combined. It is characterized in that the generated combined signal is generated and the generated combined signal is output.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. A first embodiment of the present invention will be described with reference to the drawings. Figure 1
FIG. 3 is a diagram showing an example of a configuration of a receiving circuit (receiving device) including an interference wave removing method according to the first embodiment of the present invention.

In FIG. 1, 1 is an antenna and 2 is a high frequency band pass filter (high frequency BP) for removing unnecessary components.
F), 3 is a low noise amplifier, 4 is a mixer, 5 is a control unit 11
A local oscillator whose oscillation frequency can be set on the basis of a signal from (described later), 6 is an intermediate frequency BPF, 7 is a variable gain amplifier, 8 is an intermediate frequency input signal, carrier signal level, I, Q baseband signal and I , A demodulator having a demodulation circuit for generating a Q base signal level and the like, and a control unit 11 having a control circuit for controlling the local oscillator 5, the demodulator 8, the interference wave removing unit 20, and the variable filter 30. 20
Is an interference wave removing unit (interference wave circuit), which is composed of a phase shifter 21 having a 90 ° phase shift circuit, sampling circuits 22 and 23, and an adder 24. Reference numeral 30 is a variable filter that changes the characteristics in accordance with the sampling setting of the interference wave removing unit 20, and removes unnecessary components of the output signal of the interference wave removing unit 20. In this embodiment, an example will be described in which an interference wave removing unit 20, a variable filter 30, and a control unit 11 realize an interference wave removing method (interference wave removing system).

The operation of the receiving circuit configured as described above is the same as that of the conventional example, and therefore its explanation is omitted, and the operation of the interfering wave removing section 20 which is the center of this patent will be described with reference to FIGS. 4 will be used for explanation. In FIG. 2, a thin line is an interference signal included in the received signal, and a thick line is a desired signal included in the received signal, that is, a signal to be extracted.
In this embodiment, it is assumed that the interference signal is a signal whose phase changes by 90 ° when passing through the phase shifter 21.

First, the received signal generated by the antenna 1 is
The high frequency BPF 2 removes an interference wave and limits the band, and the low noise amplifier 3 amplifies the signal. The output of the low noise amplifier 3 is added to the interfering wave remover 20. In the case where a strong level interfering wave signal is present in the received signal with respect to the desired signal, the demodulator 8 is supplied with a sufficient input signal level by the standard gain of the variable gain amplifier 7, The error rate of the specified information in the preamble area at the beginning of the format deteriorates. Based on the relative relationship between the signal level and the error rate, the control unit 11 determines that the interfering wave signal is larger than the desired signal and operates the interfering wave removing unit 20. In order to simplify the explanation of the interference wave removing operation, the interference wave removing unit 20 of FIG. 1 has a two-stage interference wave level reducing circuit in which the phase shifter 21 is only 90 °.

The demodulator 8 uses the carrier signal as decision information.
Level, desired signal level obtained from demodulated I and Q signals
(√ (I² + Q² )) ((√ (I² + Q² )) Is (I
² + Q ² ) Means the square root of. same as below. ), Preah
If there is a BER in the amble section and the interference wave signal strength is large,
Carrier wave signal level is high, desired signal level (√ (I² + Q
² )) Is small relative to the noise level, BE of the preamble part
R is in a lowered state. The signal at this time is, for example, as shown in FIG.
As shown in (A), you want a high-level interfering signal.
The signal has a superimposed waveform. The part indicated by X is a sump
This is the output signal of the ring circuit 21. Also, in FIG.
Represents the signal that has passed through the phase shifter 21. Control
The control unit 11 includes a sampling circuit 22 of the interference wave removing unit 20.
Set the sampling timing and width to. Value to set
Is a 90 ° phase shift with respect to the expected jammer signal frequency.
Signal that has passed through the phase shifter 21 (waveform in FIG. 2B)
Of sampling circuit 23 for sampling
Signal (portion indicated by Y in FIG. 2B) and sampling
The sampling signal of the circuit 21 (the portion indicated by X in FIG. 2A)
Minutes) will be set continuously. Sampling pulse
Is the zero-cross pulse obtained by detecting the zero-cross point
When the sampling circuit autonomously generates
It may be.

The output signal of the sampling circuit 21 and the output signal of the sampling circuit 23 are combined by the adder 24,
For example, it becomes a continuous signal as shown by the waveform in FIG. FIG. 2C shows an example of the output signal of the adder 24. The output signal of the adder 24 has unnecessary harmonics and low frequency components removed by the filter 30. As shown in the waveform of FIG. 2D, an output signal is obtained in which the interference wave signal level is lowered and the desired signal level is maintained. FIG. 2D shows an example of the output signal of the filter 30. The filter 30 allows the characteristics to be changed by the control unit 11 based on the frequency relationship between the interference wave signal and the desired signal.
Since the received signal after the filter 30 is handled in the same way as the conventional example, the description is omitted. Here, “continuous” means that there is no missing period in the signal waveform (envelope waveform). FIG. 2C is a diagram in which FIGS. 2A and 2B are taken out by the sampling pulses X and Y, respectively, and combined. If adjacent pulses of the sampling pulses X and Y are adjacent to each other at zero in time, basically, the waveform is not cut. However, the original waveform can be reproduced from the sampling theorem even if it is cut off in a short period.

As described above, according to the present invention, when the interfering wave signal level is extremely higher than the desired signal and the error rate is deteriorated, the phase of the interfering wave signal is changed with respect to the desired signal and the zero cross point is set. At the same time as sampling for a fixed period at the center, the phase and sampling width are set or controlled so that each sampling signal of the phase-changed signal is continuous, so it is possible to reduce the interfering wave signal level in the combined signal. Is. As shown in Figures 1 and 2,
In the case of 2-sampling in which the phase is changed by 90 °, the interfering wave signal level is about 1 / from the Fourier series expansion of the repeated sampling waveform near the zero cross point of the interfering wave signal.
Reduced to 8. In the first embodiment, the case of 2-sampling in which the 90 ° phase is changed is described. However, since 0 ° and 90 ° signals can be combined to generate a signal of an arbitrary phase,
In the case of 5 samplings in which the phase is changed by °, ± 45 °, ± 90 °, it is possible to further reduce the level. In this way, if the number of samplings is large, the sampling width becomes short, the interference wave signal level in the sampling width becomes smaller and smaller, the interference wave signal energy is shifted to the high frequency region, and most of it can be removed by the filter 30. A big improvement can be expected.

Next, referring to FIGS. 3 and 4, a first embodiment will be described.
An example of an implementation circuit of the interference wave removing unit 20 in FIG.
In FIG. 3, the phase shifter 21 includes a variable phase shifter 21A and a phase shift error corrector 21B. The phase shifter 21 is
For example, there is a circuit as shown in FIG.
A primary CR 90 ° phase shift circuit as shown in 2 or a primary CR filter (LPF (B2), HPF (B1)) shown by B1 and B2 in FIG. When a filter is used, the effect of lowering the interference wave signal level can be obtained as a filter characteristic. Further, variable phase shift can be realized by adopting an element such as a voltage-dependent type vari-gap capacitor as a constituent capacitor, and can be realized by an element in an LSI. The sampling circuits 22 and 23 can be realized by a combination of a comparator and a Schmitt trigger circuit, and the sampling width and fine timing settings are made by the information from the control unit 11. Reference numeral 24 denotes an adder, which can be realized by, for example, a Gilbert cell circuit including transistors 241-246 and resistors 247-252. Other components include decoupling capacitors 261, 262 and power supplies 263, 264.
Reference numeral 300 is a filter condenser for removing harmonics.

Next, the circuit operation of the adder 24 realized by the Gilbert cell circuit shown in FIG. 3 will be described. The input signal is
The sampling pulse is applied to the transistors 241 and 245 of the Gilbert cell circuit, but at the same time, a sampling pulse based on the zero-cross point indicated by X in FIG.
2 is generated and is a constant current source transistor 243
Is kept active for a certain period, the input signal is amplified by the transistor 241 and output to the resistor 248. Similarly, the input signal whose phase is changed by 90 ° by the phase shifter 21 is applied to the transistors 242 and 244,
At the same time, the sampling circuit 23 generates a zero-cross point-based sampling pulse indicated by Y in FIG.
Since the transistor 246 serving as a constant current source is kept active for a certain period, the input signal is amplified by the transistor 244 and output to the resistor 250.

In such an operating condition, the transistor 2
Since the sampling pulses applied to 43 and 246 have an interpolating relationship such that they are continuous with each other, when the transistor 241 is active, the transistor 244 connected to the resistor 248 is in the inactive state.
The received signal whose phase has changed is not amplified, and the resistor 248
Is not output to. Similarly, during the period when the transistor 246 becomes active, the transistor 244 becomes active and the transistor 241 becomes inactive, so that
Only the signal whose phase is changed by 0 ° is amplified and output to the resistor 248. The resistor 248 operates as described above.
2C, a synthesized sampling signal in which the DC voltage does not change during the sampling period is obtained, and when the harmonic component is removed by the capacitor 30, FIG.
It is possible to obtain an output signal in which the interference wave level of is reduced. Although the example of the realizing means of the first embodiment has been described, the transfer circuit, the sampling circuit, and the adder are circuits that can be easily integrated into an LSI, and miniaturization is highly feasible.

An example of the phase shifter (phase shift circuit) will be described below. Generally, the transfer function of a first-order filter, such as an LPF (B2 in FIG. 4), is H (S) = a / (a + s),
It can be expressed by s = jω (a = 2πfa, fa is the interfering wave frequency where the bar (arrow) stands in FIGS. 4C1 and C2), and H (jω) = a (a−jω) / (a ² + ω
² ) Therefore, the voltage gain is | H (ω) | =
It becomes a / √ (a ² + ω ² ). (√ (a ² + ω ² ))
Means the square root of (a ² + ω ² ). same as below. Since the phase is tan θ = −ω / a, at ω = a, the voltage gain | H (ω) | = 1 / √2 (-3d in voltage decibel display)
B). The phase is tan θ = −1 (phase is −45 °). If this circuit is connected in two stages, the phase of the interfering wave signal will be -4.
This means that 5 ° + (− 45 °) = 90 ° can be changed, and at the same time, its amplitude can be decreased by −3 dB + (− 3 dB) = − 6 dB (can be reduced to 1/2). That is, it means that at the same time as changing the phase, the interfering wave signal level can be reduced to half.

Incidentally, in the HPF (B1 in FIG. 4), H
(S) = s / (a + s), H (jω) = ω (ω−j
a) / (a ² + ω ² ). The voltage gain is | H (ω) | = ω
/ √ (a ² + ω ² ). Since the phase is tan θ = −a / ω, when ω = a, the voltage gain | H (ω) is similar to the LPF.
│ = 1 / √2 (-3 dB in voltage decibel display). The phase is tan θ = −1 (phase is −45 °).

The phase-shifting circuit transfer function of the phase-shifting circuit A1 of FIG. 4 is H (S) =-(a-s) / (a + s), H (jω).
^{= - ((a 2 -ω 2} ) -j2aω) / (a 2 + ω 2).
Therefore, the voltage gain is | H (ω) | = 1 (not dependent on ω, 1: the amplitude does not change). The phase is tan θ = −j2a
Since ω / (a ² −ω ² ), when ω = a, the voltage gain | H
(Ω) | = 1 (independent of ω: 1: amplitude does not change).
The phase is tan θ = −infinity (−90 ° in phase). In this circuit, only the phase shift can be changed by 90 ° without changing the amplitude.

Similarly, the phase shift circuit transfer function of the phase shift circuit A2 in FIG. 4 is H (S) = (a-s) / (a + s), H
(Jω) = ((a ² −ω ² ) −j2aω) / (a ² + ω
² ). Therefore, the voltage gain is | H (ω) | = 1 (not dependent on ω, 1: the amplitude does not change). The phase is tan θ = −
Since j2aω / (a ² −ω ² ), at ω = a, the voltage gain | H (ω) | = 1 (not dependent on ω, 1: amplitude does not change). The phase is tan θ = -infinity (-90 in phase
°). Even in this circuit, only the phase shift can be changed by 90 ° without changing the amplitude. A phase shift circuit can be realized by using the above circuits.

As described above, in this embodiment, in order to avoid the intermodulation and the saturation due to the strong level interfering wave signal, the interfering wave signal compression for lowering the interfering wave signal level is provided before the mixer where the intermodulation is likely to occur. The interference wave removing method has been described which is improved by providing the interference wave removing unit composed of the circuit and the filter. The receiving circuit of this embodiment includes a bandpass filter 2 for selecting a received signal, a low noise amplifier 3 for amplifying the signal from the bandpass filter 2, and an interference wave removing unit 2.
0, the interference wave removing unit 20 samples a plurality of phase shifters 21 that change the phase of the received signal from the low noise amplifier 3 and the output signals of each phase shifter 21 at a specific timing and a specific width. Sampling circuits 22 and 23 for
It has an adder 24 that synthesizes the respective sampling signals. Further, the receiving circuit includes a variable filter 30 for removing unnecessary components of the output signal of the adder 24, and an interference wave removing unit 20.
, A local oscillator 5, an intermediate frequency bandpass filter 6 that removes unnecessary components of the intermediate frequency signal, a variable gain amplifier 7 that amplifies to a specified signal level, and an intermediate From the frequency signal I,
The demodulator 8 for converting into a Q baseband signal and the phase shift, timing, sampling width, filter characteristic of the interfering wave removing unit from the demodulated data information, the gain of the variable gain amplifier and the like are controlled, and at the same time the frequency of the local oscillator is set. And a control unit 11. The receiving circuit provides an interfering wave removing method for reducing the level of an interfering signal larger than a desired signal.

Further, by sampling at the zero-cross points of a plurality of received signals whose phases are changed or at a time based on the zero-cross points, the phases of the received signals and the sampling width are changed so that the respective sampling signals are continuous. The present invention provides a method of removing an interference wave that reduces the level of the interference wave.

Further, the present invention provides a method for removing an interfering wave in which the filter characteristic of the filter 30 is changed according to the number of samplings to lower the level of the interfering wave.

Embodiment 2. Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Figure 5
FIG. 6 is a configuration diagram of a receiving circuit including an interference wave removal circuit according to the second embodiment of the present invention, and FIG. 6 is a flowchart diagram for switching between normal reception and interference wave removal unit operation reception. Figure 5
In the above, 1 is an antenna, 2 is a high frequency BPF for removing unnecessary components, 3 is a low noise amplifier, and in particular, a low noise variable gain amplifier is used in this embodiment. Hereinafter, in this embodiment, the low noise variable gain amplifier 3 will be described. 4 is a mixer, 5 is a local oscillator whose oscillation frequency can be set by a signal from the control unit 11, 6 is an intermediate frequency BPF, 7 is a variable gain amplifier, 8 is a carrier signal level from the intermediate frequency input signal, I, Q base. A demodulator having a demodulation circuit for generating a band signal and I, Q base signal levels, and the like, 11 a control unit having a control circuit for controlling the local oscillator 5, the demodulator 8, the interference wave removing unit 20, and the variable filter 30. 20
Is an interference wave removing unit, which is a phase shifter 2 having a 90 ° phase shift circuit.
1, the sampling circuits 22 and 23, and the adder 24. Reference numeral 15 is a switch (SW) for bypassing the interfering wave removing unit 20, and 30 is a variable filter for changing the characteristic in accordance with the sampling setting of the interfering wave removing unit, which removes unnecessary components of the output signal of the interfering wave removing unit 20. Remove.

The operation of the receiving circuit configured as described above is basically the same as that of the first embodiment, and therefore omitted.
The bypass operation of the interference wave remover 20 will be described with reference to the flowchart of FIG. In the initial state, initial values are set for the variable gain amplifiers 3 and 7, and SW1
5 is set to the normal reception state of the bypass state (S60
~ S62). The demodulator 8 uses the carrier level (S63), the desired signal level (√ (I ² + Q ² )) obtained from the demodulated I and Q signals (S65), the error rate in the header synchronization section and the frame error rate (S65) as the determination information. There is S68). When the intensity of the received signal is large, the carrier level becomes large (large in S64), so the gain of the variable gain amplifier 7 is adjusted (S62), and the input signal level to the demodulator 8 is set to the specified value. In this state, if the interference wave signal is large, the desired signal level (√ (I ² + Q ² )) is small (small in S67).
SW15 is switched to operate the interfering wave removing unit 20 (S
71).

If the interfering wave signal level is small and the desired signal level (√ (I ² + Q ² )) is proper (S67), the error rate of the header synchronization part is measured (S68), and if it is less than the specified value (S69). (Small) continues the normal reception state (S70). If the interfering wave signal level is small and the desired signal level (√ (I ² + Q ² )) is large (large in S67), the gain of the variable gain amplifier 7 is adjusted (S62) to set the specified input signal level to the header. The error rate of the synchronization unit is measured (S68), and if the error rate is equal to or less than the specified value (S69 is small), normal reception is continued (S70). When the error rate is equal to or higher than the specified value (large in S69), the interference wave is expected to be mixed, so that the SW15 is switched and the interference wave removing unit 20 is operated (S).
71).

When the interfering wave removing unit 20 is operating, the first embodiment is performed.
Similar to the above description, the sampling signals of the output signals of the plurality of phase shifters 21 are set to be continuous, the level of the interference signal is reduced, and the gain is adjusted again (S62). When the carrier level is high, the desired signal level (√ (I ² + Q ² )) is high, and the synchronization part error rate is deteriorated, the desired signal level is high and the low-noise variable gain amplifier 3 and mixer 4 are It is expected that cross modulation will occur. For this reason,
Even when the low noise variable gain amplifier 3 gain is decreased (S61) and at the same time the variable gain amplifier 7 gain is increased (S62) and the error rate is measured again (S68) before the operation of the interfering wave removing unit 20 is performed. When the error rate is deteriorated, the reception performance can be improved by further using the gain control (S62) and the operation of the interference wave removing unit 20 (S71) together. As described above, in the present embodiment, the combination of the adjustment of the variable gain amplifier and the operation of the interfering wave removing unit is performed based on the carrier signal level, the I, Q baseband signal, the I, Q base signal level, etc. Thus, the effect of obtaining better reception performance can be expected.

As described above, in the interference wave elimination system of this embodiment, the low noise amplifier 3 is composed of a variable gain amplifier, and the adder 24 output of the interference wave elimination unit 20 and the low noise amplifier 31 output are combined. SW15 for switching is provided, and demodulator 8
Based on the demodulated data quality such as the carrier signal level and demodulated signal level, the bit error rate (BER), and the frame error rate (FER) obtained from the above, an interfering wave removing method for controlling the amplifier gain and the interfering wave removing operation is provided. It is a thing.

Embodiment 3. Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Figure 7
FIG. 8 is a diagram showing a configuration of a double superheterodyne receiver circuit according to a third embodiment of the present invention, in which an interference wave cancel circuit is arranged in a first intermediate frequency band. In FIG. 7, 1 to 11, 20, and 30 are the same as those in the first embodiment, and thus the description thereof is omitted. 5A is the same as the local oscillator 5 in FIG. 5B is a second local oscillator for converting to a second intermediate frequency, and 14 is a second mixer for converting to a second intermediate frequency signal. Reference numeral 16 is a second intermediate frequency BPF, and 17 is a variable gain amplifier at the second intermediate frequency. In the following description, 4 is a first mixer, 5A is a first local oscillator, 6 is a first intermediate frequency BPF, and 7 is a variable gain amplifier having a first intermediate frequency.

The operation of the receiving circuit configured as described above is the same as that of the first embodiment, and therefore its explanation is omitted.
Further, the output signal of the variable gain amplifier 7 described in the explanation of the operation of the first embodiment is the first intermediate frequency signal. The operation of the interfering wave removing unit 20 at the first intermediate frequency will be described with reference to FIG. The first intermediate frequency signal output from the variable gain amplifier 7 having the first intermediate frequency has already been removed of unnecessary components including the interfering wave signal at the first intermediate frequency BPF 6, and the second intermediate frequency signal which is the input signal of the demodulator 8 is removed. The control unit 11 sets the gain to the variable gain amplifier 7 having the first intermediate frequency and the variable gain amplifier 17 having the second intermediate frequency so that the frequency signal becomes constant. The interference wave removing unit 20 that has received the output signal of the variable gain amplifier 7 of the first intermediate frequency is similar to the interference wave signal in the band of the first intermediate frequency BPF6 as in the case of the operation description of the first embodiment. The first intermediate frequency BPF6
In contrast, it becomes unnecessary to adopt a narrow band BPF having a steep attenuation characteristic like the first intermediate frequency BPF 6 in the conventional embodiment. As described above, in the present embodiment, the interference wave removing unit 20 can be arranged in the intermediate frequency band to reduce the in-band interference signal level. Therefore, the BPF to be used has a feature that a small and inexpensive one can be adopted. Since the wave removing unit 20 can be realized by the CR component and the circuit in the LSI, the reception circuit can be downsized as a result.

As described above, according to the interference wave removing method of this embodiment, the interference wave removing section 20 is provided at the output section of the mixer 4, and the same interference wave signal level is reduced in the intermediate frequency band. It provides a removal method.

Fourth Embodiment Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. Figure 8
FIG. 11 is a diagram showing a configuration in which a jamming wave removing unit 20 is arranged in a second intermediate frequency band in a double super-heterodyne system receiving circuit according to a fourth embodiment of the present invention. The operation is the same as that of the third embodiment, and therefore the description is omitted.

The operation of the receiving circuit configured as described above is the same as that of the third embodiment, and therefore its explanation is omitted.
The first intermediate frequency signal, which is the output signal of the variable gain amplifier 7 in the explanation of the operation of the first embodiment, is already the first intermediate frequency BP.
At F6, unnecessary components including the interfering wave signal are removed, and at the second intermediate frequency signal, unnecessary components are removed at the second intermediate frequency BPF16. Second intermediate frequency variable gain amplifier 17
Is output to the interference wave removing unit 20, but the interference wave signal in the second intermediate frequency and second band is added to the interference wave removing unit 20.
As a result, the interference wave signal level in the second intermediate frequency / first band is reduced. First intermediate frequency BP
Unlike the first intermediate frequency BPF6 in the conventional embodiment, F6 and the first intermediate frequency BPF16 do not need to adopt a narrow band BPF with a sharp attenuation characteristic, and a small and inexpensive BPF is used. There is a feature that can
Since 0 can be realized by the CR component and the circuit in the LSI, the receiver circuit can be downsized as a result.

In both the third and fourth embodiments, the interference wave removing unit 20
However, since it is arranged and operates in the intermediate frequency band, there is a feature that it is possible to easily reduce even adjacent CH interference wave signals whose frequency is fixed.

Embodiment 5. Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. Figure 9
Is a double super-heterodyne receiver circuit according to the fifth embodiment of the present invention, in which the interference wave removing unit 20A is arranged in a high frequency band and the interference wave removing unit 20B is arranged in a first intermediate frequency band. FIG. In FIG.
Since 1 to 11, 14, 16, 17, 20, and 30 are the same as those in the fourth embodiment, the description thereof will be omitted. Reference numeral 15A is a SW for bypassing the interference wave removing unit 20A in the high frequency band, and 15B is an interference wave removing unit 20B in the second intermediate frequency band.
Is a SW for bypassing. SW15A, SW1
5B, the connection is changed by the instruction of the control unit 11.

The operation of the receiving circuit configured as described above is such that the interference wave removing operation according to the second embodiment can be carried out in both the high frequency band and the intermediate frequency band, so that the interference wave signal level and the desired signal level are Depending on the relative relationship of, the optimum reception performance can be set by combining the gain adjustment of the variable gain amplifier at each frequency and the operation of the interfering wave removing unit. Although the number of filters increases, easy CR filters can be adopted, which is suitable for LSI, and can be made smaller and have higher performance.

As described above, in the interference wave removing method of this embodiment, the interference wave removing section 20 is provided in different frequency bands,
The same object is to provide a method of removing an interference wave that reduces the level of a similar interference wave signal.

Sixth Embodiment Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. Figure 10
FIG. 9 is a diagram showing a configuration of a superheterodyne receiver circuit according to a sixth embodiment of the present invention, in which a plurality of interfering wave elimination circuits are arranged in an intermediate frequency band. In FIG. 10, 1 to 11, 17, 20, and 30 are the same as those in the first embodiment, and the description thereof will be omitted. Reference numeral 200 denotes a composite interference wave removal unit including interference wave removal units 20A to 20N in the intermediate frequency band, intermediate frequency variable gain amplifiers 17A to 17N, and filters 30A to 30B. Compound interference wave removing unit 20
In the case of 0, the gain adjustment and the interference wave removing operation are performed according to the instruction of the control unit 11.

In the operation of the receiving circuit configured as described above, since the interference wave removing operation in the second embodiment is repeatedly executed in the intermediate frequency band, the interference wave signal level is much higher than the desired signal level. Also, it is possible to reduce the interference wave level. Even if a BPF having a gentle attenuation characteristic is adopted, the complex interference wave removing unit can be realized by an easy CR circuit and an LSI circuit, so that the receiver circuit can be made compact and have high performance. Also, here, the series interference removal operation was explained for a single-frequency interference signal, but even if there are multiple interference signals exceeding the desired signal level at different frequencies, the phase change setting at each stage can be changed. The same effect can be obtained with. When a plurality of interfering wave removing units are arranged in parallel in a single frequency band, it is possible to reduce the interfering wave signals over a wide band in parallel by using the BPF together.

As described above, according to the interference wave removing method of this embodiment, the interference wave removing section 20, the plurality of variable gain amplifiers for connecting them and adjusting the signal level, and the filter for removing the unnecessary component are connected in series. The present invention provides an interfering wave removing method in which a plurality of interfering wave removing operations are arranged in multiple stages to repeatedly reduce the level of a single interfering wave signal.

Further, a plurality of the interfering wave removing units 20 are arranged in parallel to provide an interfering wave removing method for reducing the plurality of interfering wave signal levels (a plurality of types of the interfering wave signal levels) at the same time in parallel. To do.

Embodiment 7. In the above embodiment, the case where the interference wave removing method includes the interference wave removing unit 20, the filter 30, and the control unit 11 has been described. However, a case where only the interference wave removing unit 20 is provided may be considered. In particular,
When the frequency of the interfering wave is fixed, it is possible to remove the interfering wave even if the filter 30 or the control unit 11 is not provided. Further, the interference wave removing method may be a case where the interference wave removing unit 20 and the filter 30 are provided. In addition, configurations other than the above may be used.

Further, in the above embodiment, the case where the interfering wave removing unit 20 is realized by hardware including a phase shifter, a sampling circuit, and an adder has been described as an example. However, the interference wave removing unit 20 may have a configuration other than the above, and is not limited to hardware. The interference wave removing unit 20 uses firmware,
It may be software, or any combination of hardware, firmware, and software.

[0061]

According to the method and method for removing an interfering wave of the present invention, only the interfering signal is changed in phase, and sampling is performed so as to be continuous with respect to a desired signal which does not cause a phase change at each zero-cross point of each phase change signal. Since only the interfering wave signal level is lowered, a cheap BPF of the receiving circuit that can easily realize the filter characteristics can be adopted, and the interfering wave removing unit can also be realized by the CR circuit and the circuit in the LSI. The receiving circuit is small and inexpensive.

In the interference wave elimination system and method of the present invention,
The carrier level, demodulated signal level, and error rate value in the specified value interval are used as judgment parameters, and optimization is performed by the combined control of the voltage gain control of the receiving circuit and the interference wave elimination operation. On the other hand, it has a feature that good reception performance can be obtained.

In the interference wave elimination system and method of the present invention,
The interference wave removal function is placed in the high frequency part, the intermediate frequency part, or in multiple stages at the same frequency to reduce the interference wave signal level, so the filter used in the receiving circuit can handle with a gentle attenuation characteristic. , A CR filter or the like can be adopted, and the receiving circuit can be easily integrated into an LSI.

Further, according to this interference wave removing method, based on the signal output from the demodulator 8, the carrier wave signal level, the demodulation signal level, and the bit error rate are used, and the amplification gain device and the interference wave removing unit are provided. Can be controlled.

Further, according to this interference wave removing method, it is possible to reduce the interference wave signal level even in the signal of the intermediate frequency band.

Further, according to this interference wave elimination method, the interference wave signal level can be reduced in the signals of different frequency bands.

Further, according to this interference wave removing method, the interference wave removing operation is performed in multiple stages by arranging the combination of the interference wave removing unit, the filter and the variable gain amplifier in series, and a single interference wave signal is obtained. The level reduction can be repeated.

According to this interference wave removing method, by disposing a plurality of interference wave removing units in parallel, it is possible to remove a plurality of interference wave signal levels in parallel.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a receiver circuit showing a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram of an interference wave removing unit of the present invention.

FIG. 3 is a diagram showing an example of an implementation circuit of an interference wave removing unit of the present invention.

FIG. 4 is a diagram showing an example of an implementation circuit of an interference wave removing unit of the present invention.

FIG. 5 is a block diagram of a receiver circuit showing a second embodiment of the present invention.

FIG. 6 is a control flow chart of the receiving circuit showing the second embodiment of the present invention.

FIG. 7 is a configuration diagram of a receiver circuit showing a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a receiver circuit showing a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of a receiving circuit showing a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram of a receiver circuit showing a sixth embodiment of the present invention.

FIG. 11 is a block diagram of a receiving circuit showing a conventional embodiment.

[Explanation of symbols]

1 antenna, 2 filter (high frequency BPF), 3,
13 low noise amplifier, 4,14 mixer, 5,5A, 5
B local oscillator, 6, 6A, 6B, 16 filter (intermediate frequency BPF), 7, 17 variable gain amplifier (intermediate frequency), 8 demodulator, 9 level detector, 10 filter, 11 controller, 15, 15A, 15B Switch (SW), 20, 20A, 20B, ... 20N Interfering wave remover, 21 Phase shifter, 21A Variable phase shifter, 21B
Phase shift error corrector, 22, 23 Sampling circuit, 2
4 adder, 30, 30A, 30B variable filter,
241-246 transistors, 247-252 resistors, 261,262 decoupling capacitors,
263,264 Power supply, 300 filter condenser.

Claims (12)

[Claims] 1. An interference wave for inputting a received signal, generating a plurality of signals having different phases from the input received signal, sampling each of the plurality of signals, and generating a combined signal obtained by combining the plurality of sampled signals. An interfering wave removing method comprising a removing unit. 2. The interference wave removing method further comprises a filter for inputting a composite signal from the interference wave removing unit, removing an unnecessary component from the composite signal and outputting the composite signal. Interference wave removal method. 3. The interference wave removing method further reduces a specific frequency component from the received signal by using any one of a degree of shifting the phase of the received signal, a sampling timing, and a sampling width. The interfering wave removing method according to claim 2, further comprising a control unit for controlling the interfering wave removing unit. 4. The interference wave removing system according to claim 3, wherein the control unit controls the characteristic of the filter in correspondence with the characteristic of the interference wave removing unit. 5. The control unit controls sampling timing based on either one of a zero-cross point of the received signal and a point with the zero-cross point as a reference, and a signal sampled from each of the plurality of signals is controlled. 4. The interference wave removing method according to claim 3, wherein the phase of the received signal and the sampling width are controlled so as to be continuous. 6. The interfering wave removing unit receives a received signal, samples a received received signal, and a phase shifter that receives the received signal and shifts the phase of the received signal. The phase shifter inputs a signal whose phase is shifted, a second sampling circuit for sampling the input signal, a plurality of input signals from the first sampling circuit and the second sampling circuit, respectively. 6. An interfering wave removing method according to claim 1, further comprising an adder configured to combine the signals of 1 to generate a combined signal. 7. The interference wave removing method further comprises a switch for switching and outputting the received signal and the combined signal output from the interference wave removing unit, and the control unit includes a quality of the received signal. 4. The interference wave removing method according to claim 3, wherein the switch is switched based on the above. 8. The method of removing interference wave according to claim 1,
The receiving device for converting the signal into a signal in the intermediate frequency band is provided, and the interference wave removing unit inputs the converted signal in the intermediate frequency band. Interference wave removal method. 9. The interference wave removing method is provided in a receiving device for receiving the received signal and converting the received signal into a signal of a different frequency band, wherein the interference wave removing method removes at least two interference waves. The interfering wave removing unit inputs a signal before conversion as a reception signal, and the other interfering wave removal unit inputs the converted signal as a reception signal. 6. The interference wave removing method according to any one of 6 above. 10. The interference wave elimination method further comprises a variable gain amplifier for adjusting a signal level, and the interference wave elimination method comprises a plurality of combinations of the interference wave elimination unit, the filter, and the variable gain amplifier. Prepare,
7. The interference wave removing method according to claim 2, wherein the plurality of combinations are arranged in series. 11. The interfering wave removing method includes a plurality of interfering wave removing sections, and the plurality of interfering wave removing sections are arranged in parallel. Interference removal method. 12. A reception signal is input, a plurality of signals having different phases are generated from the input reception signal, each of the plurality of signals is sampled, and a composite signal is generated by combining the plurality of sampled signals. A method of removing an interfering wave, which comprises outputting the combined signal.