JP2009253314A - High frequency reception part and high frequency device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute the control of starting or stopping the operation of a noise cancellation part by detecting and determining the input signal level of a weak electric field at a high speed. <P>SOLUTION: A high frequency reception part is provided with a signal level determination circuit 149 for determining the input signal level to an input terminal 117 by comparing a second AGC voltage with a predetermined reference voltage and the noise cancellation part 127 connected between an antenna 119 and an amplifier 139 for noise-canceling noise signals which jump into the antenna 119, and the noise cancellation part 127 is controlled on the basis of the determined result of the signal level determination circuit 149. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention has an image display unit such as a mobile phone, a portable game machine, a portable computer, a portable dictionary, a car navigation system, etc., and a signal from the image forming unit to the image display unit. The present invention relates to a high-frequency receiving unit that displays an image and a high-frequency device using the same.

  In recent years, the above-described high-frequency devices are very light and have been miniaturized due to the progress of miniaturization of parts and integration of semiconductor elements. For this reason, attempts are being made actively to enhance the functions of high-frequency devices.

  As a result, the high-frequency device has functions such as a mobile phone, a portable game machine, a portable computer, a portable dictionary, and a car navigation system, and can also watch TV broadcasts.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2008-22294 A

  However, in a conventional high-frequency device, a clock signal output from the high-frequency device or a part of its harmonic signal becomes a noise signal and jumps into the antenna. Thereby, the reception quality in a weak electric field deteriorated.

  The deterioration of the reception quality is determined by BER or C / N, and based on the determination result, the noise signal jumping into the antenna can be canceled by the noise cancellation unit, and the reception quality of the input signal level of the weak electric field is improved. .

  However, since this deterioration in reception quality is determined by BER or C / N, a long determination time is required. For this reason, it was a weak electric field reception, and it was not possible to cope with reception conditions that change every moment due to fading or the like generated during movement, and reception quality deteriorated.

  For this reason, since the noise canceling operation using the noise canceling unit needs to be operated at all times other than the input signal level of the weak electric field, it is not suitable for high-frequency devices with low power consumption.

  In this way, the purpose is to detect and determine the input signal level of the weak electric field at high speed and to control to start or stop the operation of the noise canceling unit.

  In order to achieve this object, the high-frequency receiving unit of the present invention includes a signal level determination circuit that determines the input signal level to the input terminal by comparing the second AGC voltage with a predetermined reference voltage; A noise canceling unit that is connected between the antenna and the first amplifier and that cancels noise signals that have jumped into the antenna is provided, and the noise canceling unit is controlled based on a determination result of the signal level determination circuit.

  This achieves the intended purpose.

  As described above, in the high frequency receiving unit of the present invention, the second AGC voltage is compared with a predetermined reference voltage to determine the input signal level to the input terminal, the antenna, A noise canceling unit is provided that is connected to the first amplifier and cancels a noise signal that has jumped into the antenna, and controls the noise canceling unit based on a determination result of the signal level determination circuit.

  As a result, for example, even in a reception state where the reception level changes every moment due to fading that occurs during movement, such as weak electric field reception, the input signal level is set by the signal level determination circuit using the second gain control voltage. Can detect and judge at high speed.

  Therefore, for example, since the noise canceling unit can be operated only in a weak electric field, a high-frequency device with low power consumption can be realized.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of the high-frequency device 101. In the embodiment of the present invention, a high-frequency device 101 that can receive a high-frequency signal that is a one-segment broadcast signal using the UHF band will be described as an example.

  The high-frequency device 101 includes an antenna matching unit 126 to which an antenna 119 is connected, a high-frequency receiving unit 103 that receives a high-frequency signal, a mobile phone, a portable game machine, a portable computer, a portable dictionary, a car navigation system. And the like, a decoding unit 122 to which the output terminal 121 of the high frequency receiving unit 103 is connected, an output of the decoding unit 122 is connected to the input 107a, and an output of the main unit 105 is output to the input 107b. A connected baseband signal processing unit 107, an image display unit 109, an audio output unit 111, a baseband signal processing unit 107, a high frequency receiving unit 103, to which signals from the baseband signal processing unit 107 are respectively supplied, The system control unit 113 controls the main body unit 105 and the like.

  In addition, the baseband signal processing unit 107 and the system control unit 113 constitute an image forming unit 115.

  The antenna matching unit 126 is connected to a matching unit 124 that matches the input impedance of the antenna 119 and a high-frequency amplifier 125 that amplifies a high-frequency signal in order from the input to the output.

  The high frequency receiver 103 is provided with an input terminal 117 to which a television signal is supplied and an output terminal 121 to which a TS (transport stream) signal is output.

  In order from the input terminal 117 toward the output terminal 121, a noise canceling unit 127 for canceling a noise signal jumping into the antenna 119, a tuner unit 129, and a demodulating unit 130 for demodulating a digital signal are connected.

  First, the configuration of the noise cancellation unit 127 will be described. The noise cancellation unit 127 includes a synthesis circuit 131 in which the input 131a and the output 131b are connected to the input and output of the noise cancellation unit 127, and a cancel signal generation circuit 133 in which an output is connected to the input 131c of the synthesis circuit 131. It consists of and.

  A noise signal extracted by the pickup antenna 135 is input to the input of the cancel signal generation circuit 133 via the wiring unit 138.

  Next, in the tuner unit 129, in order from the input to the output, an amplifier 139 having a gain control input 139a, a mixer 141 in which the output of the amplifier 139 is connected to one input, and a filter 143 for suppressing interference signals. An amplifier 145 having a gain control input 145a is provided, and an oscillator 142a controlled by a PLL circuit 142 is connected to the other input of the mixer 141.

  A gain controller 137 is connected between the output of the mixer 141 and the gain control input 139a. Further, the output of the gain controller 147 is connected to the gain control input 145 a and the input of the signal level determination circuit 149.

  Next, in the demodulator 130, an A / D converter 151 that converts an analog signal into a digital signal, a filter 153 that suppresses an interference signal, and a demodulator 155 that outputs a demodulated signal are connected in order from the input to the output terminal 121. Has been.

  The BER or C / N reception quality signal output from the demodulator 155 is input to the reception quality determination circuit 156. Further, the output signal of the filter 153 is connected to the input of the gain controller 147.

  The operation of the high-frequency device 101 configured as described above will be described below with reference to FIG.

  First, operations of the main body unit 105, the image forming unit 115, the image display unit 109, and the audio output unit 111 will be described. The main body unit 105 has functions such as a mobile phone, a portable game machine, a portable computer, a portable dictionary, and a car navigation system. For example, a baseband signal output from the main body unit 105 is input to the baseband signal processing unit 107.

  The high-frequency receiving unit 103, the main body unit 105, the baseband signal processing unit 107, the image display unit 109, and the noise cancellation unit 127 are controlled by the system control unit 113 and the like. The video signal output from the baseband signal processing unit 107 is displayed as an image by the image display unit 109, and the audio signal output from the baseband signal processing unit 107 is converted into audio by the audio output unit 111. .

  Next, operations of the antenna matching unit 126 and the high frequency receiving unit 103 will be described. A television broadcast signal is received by the antenna 119 and input to the antenna matching unit 126. The antenna matching unit 126 includes a matching unit 124 on the antenna 119 side and a subsequent high-frequency amplifier 125. Thus, impedance matching can be achieved, and reception sensitivity can be ensured even when the antenna 119 is shortened.

  Further, in the noise canceling unit 127, the noise signal that has jumped into the antenna 119 from the noise generation source is subjected to noise cancellation, and then input to the tuner unit 129. From the output of the tuner unit 129, an intermediate frequency signal or a baseband signal that is gain-controlled and frequency-converted by the mixer 141 is output.

  This intermediate frequency signal or baseband signal is input to the demodulator 130, and further, the demodulated signal is output via the output terminal 121.

  Further, the demodulated signal is input to the decoding unit 122. A TS signal is output from the decoding unit 122. This TS signal is input to the baseband signal processing unit 107 to output a video signal and an audio signal, which can be viewed by the image display unit 109 and the audio output unit 111.

  In addition, the system control unit 113 can select the reception channel of the high frequency reception unit 103 and further system-control the demodulation unit 130, the decoding unit 122, and the like. In this way, television signals can be received mainly by the high-frequency receiving unit 103, the image forming unit 115, the image display unit 109, and the audio output unit 111.

  However, the high-frequency device 101 in which the high-frequency receiving unit 103 capable of receiving television is built-in has functions such as a mobile phone, a portable game machine, a portable computer, a portable dictionary, and a car navigation system, and is further downsized. Size.

  As a result, for example, the harmonic signal of the clock signal for controlling the image forming unit 115 and the image display unit 109 or the harmonic signal of the oscillator matches the frequency of the UHF television signal.

  Due to the clock signal and the harmonic signal of the oscillator, the reception quality in the weak electric field area deteriorated. The operation of the noise cancellation unit 127 for improving the reception quality in this weak electric field region will be described below.

  The noise canceling unit 127 is connected to a pickup antenna 135 disposed in the vicinity of the noise generation source. The noise signal extracted by the pickup antenna 135 is phase-adjusted and level-adjusted by a phase shifter and an amplifier provided in the cancellation signal generation circuit 133, and is input to the input 131c of the synthesis circuit 131 as a noise cancellation signal. Is done.

  The television signal in which the noise signal that has jumped into the antenna 119 in this way is subjected to noise cancellation is input to the demodulation unit 130 via the tuner unit 129. A reception quality signal such as BER or C / N output from the demodulator 155 provided in the demodulator 130 is detected and determined by the reception quality determination circuit 156.

  This determination signal is input to the system control unit 113. The control signal from the system control unit 113 is input to the control terminal 127a of the noise cancellation unit 127, and the cancel signal generation circuit 133 performs phase adjustment and amplitude adjustment.

  By repeating this series of operations, the phase and amplitude of the cancel signal generation circuit 133 can be set to optimum values, and the noise signal jumping into the antenna 119 can be finally canceled.

  The manner in which the noise cancellation unit 127 cancels the noise signal that has jumped into the antenna 119 from this noise generation source will be described below.

  FIG. 2A is a diagram illustrating an input signal to the demodulation unit 130 before noise cancellation by the noise cancellation unit 127, and represents a television signal 165 and all noise signals 167, respectively.

  Note that, for example, an input signal level 202d (−100 dBm) is input to the input terminal 117 as a weak electric field. This input signal level 202d (−100 dBm) will be described later with reference to FIGS. The horizontal axis represents the frequency 161, and the vertical axis represents the signal level 163.

  In FIG. 2A, all noise signals 167 include a thermal noise signal 167 a that is a combination of the thermal noise power Pn related to the Boltzmann constant and the noise figure NF of the high frequency receiver 103, and the noise source to the antenna 119. This shows a case where the noise signal 167b is caused by the jumping in, and the level of the noise signal 167b is higher than the thermal noise signal 167a.

  Due to the noise signal 167b caused by jumping into the antenna 119, the C / N of the television signal 165 deteriorates, and the reception quality is impaired.

  FIG. 2B is a diagram illustrating an input signal to the demodulation unit 130 after the noise cancellation by the noise cancellation unit 127, and illustrates a state in which the noise signal 167b due to jumping into the antenna 119 is canceled. .

  In this way, since only the thermal noise signal 167a can be made with respect to the television signal 165, the C / N of the input signal level can be improved and the reception quality in the weak electric field is not impaired.

  For example, the reception sensitivity P for one-segment reception can be expressed as (Equation 1) by the thermal noise power Pn, the required Co / No after Viterbi correction, and the noise figure of the high-frequency receiving unit 303.

  Furthermore, the thermal noise power Pn can be expressed as (Equation 2).

  Thereby, the reception sensitivity P can be expressed as (Equation 3).

  That is, the reception sensitivity at the time of receiving 1 seg can be approximately the input signal level 202f (−108 dBm) when the noise figure is 5 dB. The input signal level 202f (−108 dBm) will be described later with reference to FIGS.

  Next, a signal level determination circuit 149 that can instantaneously detect and determine the reception level of a weak electric field that requires noise cancellation will be described with reference to FIGS.

  FIG. 3A is a characteristic diagram of a first gain control voltage (hereinafter referred to as AGC voltage) 201 of the amplifier 139 with respect to the input signal level 202 at the input terminal 117.

  The horizontal axis is the input signal level 202, and the vertical axis is the voltage 213. Further, the input signal level 202c is approximately −115 dBm, the input signal level 202b is approximately −50 dBm, and the input signal level 202a is approximately 0 dBm.

  In FIG. 3A, the first AGC voltage 201 is composed of a first AGC voltage 201a and a first AGC voltage 201b.

  The first AGC voltage 201a is an AGC voltage when a strong electric field signal having an input signal level 202a (0 dBm) to an input signal level 202b (−50 dBm) is input, and the output level of the mixer 141 is constant. Gain control to level.

  The first AGC voltage 201a has an upper limit voltage 213a that becomes a minimum gain when the input signal level 202a (0 dBm) is input.

  On the other hand, the first AGC voltage 201b is an AGC voltage with respect to the input signal level from the input signal level 202b (−50 dBm) to the input signal level 202c (−115 dBm), and the amplifier 139 has a maximum gain.

  The first AGC voltage 201b has a lower limit voltage 213b that has a maximum gain when the input signal level 202c (-115 dBm) is input.

  FIG. 3B is a characteristic diagram of the second AGC voltage 211 of the amplifier 145 with respect to the input signal level at the input terminal 117.

  The second AGC voltage 211 is output from the gain controller 147 to control the gain of the amplifier 145. For example, a digital filter may be used as the filter 153 to input only the desired signal in which the interference signal is suppressed together with the filter 143.

  Thereby, the desired signal output from the amplifier 145 can be controlled to a constant level. The desired signal level is such that the television signal 165 shown in FIGS. 2A and 2B becomes small in a weak electric field reception state, and as a result, Co / No 165a deteriorates.

  As is clear from this, the input signal level can be determined by the signal level determination circuit 149 by using the second AGC voltages 211b and 211c output from the gain controller 147.

  In FIG. 3B, the second AGC voltage 211 includes a second AGC voltage 211a and second AGC voltages 211b and 211c.

  The second AGC voltage 211a is an AGC voltage when a received signal having a strong electric field of the input signal level 202a (0 dBm) to the input signal level 202b (−50 dBm) is input, and the second AGC voltage 211a The output level of the amplifier 145 is set to the minimum gain so as to become the minimum level.

  The second AGC voltage 211b represents a case where there is no influence of a noise signal due to jumping into the antenna 119. The second AGC voltage 211c represents a case where there is an influence of a noise signal due to jumping into the antenna 119.

  Further, the second AGC voltage 211a has an upper limit voltage 223a that becomes a minimum gain when the input signal level 202a (0 dBm) is input.

  Further, the second AGC voltages 211b and 211c are AGC voltages with respect to the input signal level from the input signal level 202b (−50 dBm) to the input signal level 202c (−115 dBm), and the amplifier 139 has the maximum gain.

  In the second AGC voltage 211b, the input signal level 202f (−108 dBm), which is the reception sensitivity from (Expression 1), is set to the second reference voltage 223b, and the input signal level 202c (−115 dBm), which is smaller, has the maximum gain. It has a lower limit voltage 223c.

  On the other hand, the second AGC voltage 211c does not reach the lower limit voltage 223c and is a constant voltage 223d when there is no signal or when the input signal level 202c (-115 dBm) is input. This is because the noise signal from the noise generation source jumps into the antenna 119, and the noise signal level in this case is set to the input signal level 202d (−100 dBm).

  That is, the second AGC voltage 211c can be brought close to the second AGC voltage 211b by noise canceling the noise signal caused by jumping into the antenna 119 by the noise canceling unit 127.

  As described above, the second AGC voltage 211 c changes according to the input signal level input to the demodulator 130. Therefore, the second AGC voltage 211c is input to the signal level determination circuit 149, and compared with the predetermined first reference voltage 223e to determine the input signal level to the demodulator 130.

  The first reference voltage 223e is a signal that is close to the voltage 223d generated when the TV signal is a no-signal, and a noise signal caused by jumping into the antenna 119 jumps into the antenna 119, and from the noise signal level jumped into the antenna 119. This is the voltage at the second AGC voltage 211c when a large television signal is input. In this case, a large television signal can be set to an input signal level 202e (−95 dBm), for example.

  That is, the first reference voltage 223e is close to the voltage 223d of the second AGC voltage 211c generated when there is no signal, and a large TV signal is input to the noise signal jumping into the antenna 119 at the input terminal 117. It is sufficient to use the voltage when the

  The second AGC voltage 211b is the lower limit voltage 223c when the noise signal and the television signal from the noise generation source are not input to the input terminal 117.

  Therefore, when the second AGC voltage 211c is a hatched region 225 that is a voltage between the first reference voltage 223e and the lower limit voltage 223c, it can be determined that the level of the weak electric field input signal is close to the reception sensitivity point. This reception sensitivity point is the input signal level 202f (−108 dBm), which will be described later.

  Based on this determination result, the noise signal jumping into the antenna 119 can be canceled by operating the noise canceling unit 127.

  Further, since the second AGC voltage 211 is a voltage obtained by directly detecting the signal level, a voltage corresponding to the magnitude of the signal level is instantaneously output. For this reason, even if the television reception level fluctuates due to fading or the like during movement, the signal level determination circuit 149 can instantaneously determine the input signal level to the input terminal 117.

  As described above, the signal level determination circuit 149 compares and determines the second AGC voltage 211c of the amplifier 145 with the first reference voltage 223e.

  As a result, even if the reception state is weak electric field reception and is changing every moment, the reception quality deteriorates due to the noise signal radiated from the noise generation source in the high-frequency device 101 jumping into the antenna 119. It is possible to instantaneously determine the reception condition to be performed.

  Based on the determination result, the operation of the noise canceling unit 127 is started, and the noise signal jumping into the antenna 119 is canceled by the noise canceling unit 127, so that the deterioration of the reception quality at the time of receiving the television signal can be improved.

  On the other hand, when the reception condition is good, the operation of the noise canceling unit 127 can be stopped, so that the high-frequency device 101 with low power consumption can be realized.

  Next, a case will be described in which noise cancellation is performed by the noise canceling unit 127 and the reception sensitivity is a limit level at which the input signal level 202f (−108 dBm) can be received.

  At this reception sensitivity point, the noise signal 167b generated by jumping into the antenna of FIG. 2A is cancelled, but C / N 165a which is the ratio of the TV signal and the thermal noise signal 167a in FIG. Is smaller than (Equation 1) by 5.0 dB.

  In an actual experiment, even if the noise signal 167b jumped into the antenna 119 is subjected to noise cancellation, the reception sensitivity is not improved. Rather, reception quality deteriorated.

  This is because the noise signal 167b jumped into the antenna 119 is canceled by the noise and comes close to the level of the thermal noise signal 167a. It is conceivable that an influence due to the thermal noise signal 167a occurs.

  In order to improve this, the second AGC voltage 211b when the input signal level 202f (−108 dBm) in the vicinity of the reception limit point is input is used as the second reference voltage 223b, and the second AGC voltage 211b is the second When a voltage between the reference voltage 223b and the lower limit voltage 223c is reached, the noise cancellation signal output from the cancellation signal generation circuit 133 is held.

  The noise cancellation signal that holds the phase and amplitude may be supplied to the input 131a of the synthesis circuit 131 to cancel the noise. As a result, it is possible to eliminate deterioration in reception quality by the noise canceling unit 127 when an input signal near the reception sensitivity point is received.

  This eliminates the need for detection / determination of reception quality signals such as BER or C / N in the reception quality determination circuit 156, and further eliminates the need for phase adjustment / amplitude adjustment in the cancel signal generation circuit 133. Power consumption can be reduced.

  Further, when the signal level determination circuit 149 causes the second AGC voltage 211b to be a voltage between the second reference voltage 223b and the first reference voltage 223e, the operation of the noise cancellation unit 127 is started again. .

  That is, the amplitude and phase of the cancellation signal generation circuit 133 are optimized based on the determination value from the reception quality determination circuit 156, and the noise signal jumped into the antenna 119 is canceled by the noise cancellation unit 127, and the TV signal is received. To improve reception quality degradation.

(Embodiment 2)
The second embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a layout diagram of each block of the high-frequency device 301 of the present invention.

  The high frequency device 101 according to the first embodiment uses the noise canceling unit 127, whereas the high frequency receiving unit 303 of the high frequency device 301 according to the second embodiment includes a synthesis circuit 309 and cancellation signal generation circuits 133 and 305. The difference is that the noise canceling unit 307 is used.

  In addition, about the component used in FIG. 4, the same number is attached | subjected about the same thing as FIG. 1, and description is simplified.

  In FIG. 4, the output of the antenna matching unit 126 is connected to the input 309 a of the combining circuit 309, and the output 309 b of the combining circuit 309 is connected to the input of the tuner unit 129.

  Also, noise cancellation signals from the cancel signal generation circuits 133 and 305 are input to the inputs 309c and 309d of the synthesis circuit 309, respectively. Pickup antennas 135 and 311 are input to the inputs of the cancel signal generation circuits 133 and 305, respectively. They are connected via wiring parts 138 and 313, respectively.

  These pickup antennas 135 and 311 are provided, for example, close to noise generation sources of the image forming unit 115 and the image display unit 109, respectively.

  Thereby, the noise signal of the image forming unit 115 is extracted by the pickup antenna 135, and the extracted noise signal is input to the cancel signal generation circuit 133.

  Further, the noise signal of the image display unit 109 is extracted by the pickup antenna 311, and the extracted noise signal is input to the cancel signal generation circuit 305.

  The noise cancellation signals output from the cancel signal generation circuits 133 and 305 are input to the synthesis circuit 309 via the inputs 309c and 309d.

  On the other hand, noise signals from the image forming unit 115 and the image display unit 109 that have jumped into the antenna 119 are input to the input 309 a of the synthesis circuit 309.

  The noise signal jumping into the antenna 119 is canceled by the synthesis circuit 309 by the noise canceling signal.

  As described above, according to the present invention, even when a noise signal from a noise generation source jumps into the antenna 119 when a television signal is received, the plurality of pickup antennas 135 and 311 and the plurality of pickup antennas 135 and 311 are included. Are connected to the antenna 119 by a plurality of cancel signal generation circuits 133 and 305 connected to each other, and a synthesis circuit 309 to which a plurality of noise cancellation signals from the plurality of cancel signal generation circuits 133 and 305 are respectively input. Each noise signal can be canceled.

  As described above, the signal level determination circuit 149 compares and determines the second AGC voltage 211c for gain control of the amplifier 145 with the first reference voltage 223e.

  As a result, even if the reception level is weak electric field reception and the reception level changes every moment due to fading during movement, reception quality deteriorates due to the noise signal from the noise source jumping into the antenna 119. The condition can be determined instantaneously.

  Based on this determination result, the operation of the noise canceling unit 307 is started, and the noise signal jumping into the antenna 119 is canceled by the noise canceling unit 307, so that the reception quality can be improved.

  On the other hand, when the reception condition is good, the operation of the noise canceling unit 307 can be stopped, so that the high-frequency device 301 with low power consumption can be realized.

  Further, the case where noise cancellation is performed by the noise canceling unit 307 and the reception sensitivity is a limit level at which the input signal level 202f (−108 dBm) can be received is the same as in the first embodiment.

  That is, the voltage at the second AGC voltage 211c at the input signal level (−108 dBm) that is the reception limit is the second reference voltage 223b, and the second AGC voltage 211b is between the second reference voltage 223b and the lower limit voltage 223c. The operation of the noise canceling unit 307 is stopped when the voltage becomes.

  As a result, it is possible to eliminate deterioration in reception quality when an input signal near the reception sensitivity point is received. In addition, since the operation of the noise canceling unit 307 can be stopped, the high-frequency device 301 with low power consumption can be realized.

(Embodiment 3)
Hereinafter, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 5 is a layout diagram of each block of the high-frequency device 401 of the present invention.

  In contrast to the high-frequency device 301 of the second embodiment, the high-frequency receiving unit 403 of the high-frequency device 401 of the present embodiment has antennas 119 and 419, antenna matching units 126 and 426, noise canceling units 307 and 407, and a tuner. Units 129 and 429, demodulating units 130 and 430, and a diversity decoding unit 432 are provided so that diversity reception is possible.

  In addition, about the component used in FIG. 5, the same number is attached | subjected about the same thing as FIG. 1, and description is simplified.

  In FIG. 5, the noise canceling unit 407 of the high frequency receiving unit 403 includes a combining circuit 435 in which the output of the antenna matching unit 426 is connected to the input 435a and the input of the tuner unit 429 is connected to the output 435b. It includes a cancel signal generation circuit 437 connected to the input 435c and a cancel signal generation circuit 439 connected to the input 435d of the synthesis circuit 435.

  The pickup antenna 135 is connected to the inputs of the cancel signal generation circuits 133 and 437 via the wiring portion 138, and the pickup antenna 311 is connected to the inputs of the cancellation signal generation circuits 305 and 439 via the wiring portion 313, respectively. Has been.

  Further, the system control unit 113 includes one or both of a signal level determination circuit 149 (not shown) built in the tuner unit 129 and a signal level judgment circuit 429a (not shown) built in the tuner unit 429. Is output.

  Further, the system control unit 113 controls the single reception and diversity reception selection of the high frequency reception unit 403 or the noise cancellation units 307 and 407.

  As a result, the noise signal from the image forming unit 115 is input to the cancel signal generation circuits 133 and 437 by the pickup antenna 135, and the noise signal extracted by the pickup antenna 311 is input to the cancellation signal generation circuits 305 and 439.

  Each of the noise signals jumped into the antenna 119 can be canceled by the synthesis circuit 309 to which the noise cancellation signal from the cancellation signal generation circuits 133 and 305 is input.

  Similarly, each noise signal jumped into the antenna 119 can be canceled by the synthesis circuit 435 to which the noise cancellation signal from the cancellation signal generation circuits 437 and 439 is input.

  Thus, the noise signals extracted from the image forming unit 115 and the image display unit 109 by the two pickup antennas 135 and 311 are input to the two noise cancellation units 307 and 407, respectively. Further, the two noise signals jumped into the antennas 119 and 419 are canceled by the two noise cancellation units 307 and 407, respectively.

  That is, even if there are a plurality of noise signals, the noise signals jumping into the antennas 119 and 419 can be canceled by providing a plurality of pickup antennas and a plurality of noise canceling units.

  These noise-cancelled signals are input to diversity decoding section 432 via tuner section 129 and demodulation section 130, and tuner section 429 and demodulation section 430, respectively. The diversity decoding unit 432 selects or combines two input demodulated signals, and selects single reception or diversity reception.

  As described above, the high frequency device 401 capable of diversity reception extracts these noise signals even if the noise signal radiated from the noise generation source jumps into the antenna 119, as in the high frequency device 101 of the first embodiment. A plurality of noise signals can be canceled by the plurality of pickup antennas 135 and 311 and the noise cancellation units 307 and 407 to which the plurality of pickup antennas 135 and 311 are respectively connected.

  Accordingly, as in the first embodiment, the signal level determination circuits 149 and 429a (both not shown) compare the second AGC voltage 211c of the amplifiers 145 and 429a (both not shown) with the first reference voltage 223e. ·judge.

  As a result, even in a reception state where the reception level is weak electric field reception and the reception level changes every moment due to fading that occurs during movement, the reception quality is improved by the noise signal from the noise generation source jumping into the antennas 119 and 419. The deteriorated reception condition can be determined instantaneously.

  Based on the determination result, the operation of the noise canceling units 307 and 407 is started, and the noise signal jumping into the antennas 119 and 419 is canceled by the noise canceling units 307 and 407, so that the reception quality at the time of receiving the TV signal can be improved. .

  On the other hand, when the reception condition is good, the operation of the noise canceling units 307 and 407 can be stopped, so that the high-frequency device 401 with low power consumption can be realized.

  When there is only one noise generation source due to reception quality degradation, the cancel signal generation circuit 305 built in the noise cancellation unit 307 and the cancel signal generation circuit 439 built in the noise cancellation unit 407 are deleted and used. May be.

  Further, the case where noise cancellation is performed by the noise cancellation units 307 and 407 and the reception sensitivity is a limit level at which the input signal level 202f (−108 dBm) can be received is the same as in the first embodiment.

  That is, the second AGC voltage at the input signal level (−108 dBm), which is the reception limit, is the second reference voltage 223b, and the second AGC voltage 211b is a voltage between the second reference voltage 223b and the lower limit voltage 223c. When it becomes, operation | movement of the noise cancellation parts 307 and 407 is stopped.

  As a result, it is possible to eliminate deterioration in reception quality when an input signal near the reception sensitivity point is received. In addition, since the operation of the noise cancellation units 307 and 407 can be stopped, the high-frequency device 401 with low power consumption can be realized.

  As described above, the present invention can be used for mobile phones capable of receiving television signals, portable game machines, portable computers, portable dictionaries, car navigation systems, and the like.

Block diagram of a high-frequency device according to Embodiment 1 of the present invention (A) The figure which shows the input signal to the demodulator before noise cancellation, (b) The figure which shows the input signal to the demodulator after noise cancellation (A) Same as above, characteristic diagram of first AGC voltage against input signal level, (b) Same as above, characteristic diagram of second AGC voltage against input signal level Block diagram of a high-frequency device according to Embodiment 2 of the present invention Block diagram of a high-frequency device according to Embodiment 3 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 103 High frequency receiving part 117 Input terminal 127 Noise cancellation part 130 Demodulation part 137 Gain controller 139 Amplifier 141 Mixer 145 Amplifier 149 Signal level determination circuit

Claims (9)

A high-frequency receiving unit in which a noise signal of a built-in noise generation source jumps through an antenna, and an input terminal to which a TV signal from the antenna is input, and the TV signal from the input terminal is supplied and A first amplifier that is gain-controlled by a first AGC (gain control) voltage output from one gain controller, a mixer that receives a signal from the first amplifier, and a A second amplifier that is supplied with a signal and gain-controlled by a second AGC voltage output from a second gain controller; and a demodulator that receives a signal from the second amplifier, A signal level determination circuit that determines an input signal level to the input terminal by comparing the second AGC voltage with a predetermined reference voltage, and between the antenna and the first amplifier. Wherein said noise signal jumped into the antenna provided noise cancellation unit for noise cancellation, high-frequency receiving unit for controlling said noise cancellation unit based on a determination result of the signal level determination circuit is connected. The noise cancellation unit includes a cancellation signal generation circuit that adjusts a phase and a gain of a noise cancellation signal, respectively, and the television signal from the antenna is supplied to one input and output from the cancellation signal generation circuit The high frequency receiver according to claim 1, further comprising a synthesis circuit in which a noise canceling signal is supplied to the other input. The second AGC voltage when the television signal having a level larger than the noise signal level input to the input terminal by jumping into the antenna is input as the first reference voltage, and the noise signal and the The second AGC voltage when a television signal is not input to the input terminal is set as a lower limit voltage, and the noise is generated when the second AGC voltage is a voltage between the first reference voltage and the lower limit voltage. The high frequency receiving unit according to claim 2, wherein the canceling unit is operated. The second AGC voltage when the television signal in the vicinity of the reception limit point is input is set as a second reference voltage, and the second AGC voltage when the noise signal and the television signal are not input to the input terminal. Is the lower limit voltage, the second AGC voltage holds the noise cancel signal from the cancel signal generation circuit at a voltage between the second reference voltage and the lower limit voltage, and the synthesized noise cancel signal is the synthesized signal. The high frequency receiver according to claim 2, wherein the high frequency receiver is supplied to a circuit. The demodulator is supplied with a signal from the second amplifier and converts an analog signal into a digital signal, and an output signal of the A / D converter is supplied and suppresses an interference signal. 2. The filter according to claim 1, further comprising a filter and a demodulator that is supplied with an output signal from the filter and outputs a transport stream signal, and the output signal of the filter is input to the second gain controller. High frequency receiver. A decoding unit to which an output signal from the high-frequency receiving unit according to claim 1 is supplied, a baseband signal processing unit to which an output signal from the decoding unit is supplied to one input, and the baseband signal processing unit An image display unit that is connected and displays an image signal, and a system control unit that controls at least the high-frequency receiving unit and the image display unit and that receives a level determination signal output from the signal level determination circuit, A high-frequency device provided with a pickup antenna that is close to a noise generation source of any one of the image display unit, the baseband signal processing unit, and the system control unit and extracts the noise signal. The said system control part memorize | stores the optimal data of the phase and gain obtained by the said noise cancellation part for every receiving channel, and controls the said noise cancellation part for every receiving channel based on this memory | storage data. High frequency equipment. The noise cancellation unit includes a plurality of cancellation signal generation circuits and a synthesis circuit to which noise cancellation signals output from the plurality of cancellation signal generation circuits are respectively input. The high-frequency device according to claim 6, wherein a plurality of pickup antennas respectively disposed close to the plurality of noise generation sources are connected to each other. The first and second noise canceling units to which signals from the first and second antennas for receiving the television signal are respectively supplied, and the signal from the first noise canceling unit are supplied to the first input. And at least the first and second amplifiers, the first mixer, the first tuner unit provided with the first and second gain controllers, and the signal from the second noise canceling unit is the second signal. And a second tuner unit provided with at least a third and a fourth amplifier, a second mixer, a third and a fourth gain controller, and the first and second tuners. First and second demodulation units to which signals from the first and second demodulation units are respectively supplied, and diversity and decoding units to which signals from the first and second demodulation units are respectively supplied and perform diversity control and decoding; The first and second tuners First, high-frequency receiving unit according to claim 1 provided with a second signal level determining circuit on one or both either within.

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