JP2010062606A - Receiver, and electronic equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the circuit scale of a receiver. <P>SOLUTION: The receiver includes an MEMS (microelectromechanical systems) vibrator 14 for outputting a reference signal; an oscillator 15 for outputting an oscillation signal, on the basis of the reference signal output from the MEMS vibrator 14; a mixer 13 receiving the oscillation signal output from the oscillator 15; an amplifier 12 connected to an input side or an output side of the mixer 13; a signal strength detecting part 18 connected to an output side of the amplifier 12 to detect receiving intensity; a frequency fluctuation detecting part 19, connected to the output side of the mixer 13 to detect frequency fluctuations of input signal; and a control part for controlling an amplification factor of the amplifying part 12, on the basis of a detection result of the signal strength detecting part 18. The control part detects ambient temperature by the frequency fluctuation detected by the frequency fluctuation detecting part and performs control for determining the presence/absence of a reception signal, on the basis of the detected temperature and the detection result of the signal strength detecting part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a receiving device that receives a signal and an electronic apparatus using the receiving device.

  Hereinafter, a conventional receiving apparatus will be described with reference to FIG. FIG. 3 is a block diagram of an electronic apparatus equipped with a conventional receiving apparatus.

  In FIG. 3, a conventional receiving apparatus 1 includes a crystal resonator 2 that outputs a reference signal, an oscillator 3 that outputs an oscillation signal based on the reference signal output from the crystal resonator 2, and an output from the oscillator 3. A mixer 4 to which the oscillation signal is input, an amplifier 5 connected to the input side of the mixer 4, a signal intensity detector 6 connected to the output side of the amplifier 5 to detect the received intensity, A control unit 7 that controls the amplification degree of the amplification unit 5 based on the detection result of the signal intensity detection unit 6 and a temperature sensor 8 that detects the temperature of the reception device 1 are provided.

  The control unit 7 determines the presence or absence of a received signal based on the temperature of the receiving device 1 detected by the temperature sensor 8 and the detection result of the signal intensity detecting unit 6, and performs a channel search.

  Thereby, even if the amplification degree of the amplifying unit 5 varies depending on the ambient temperature, the control unit 7 determines the presence / absence of the received signal based on the determination criterion derived from the detection result of the temperature sensor 8, so that the influence of the ambient temperature is not so much. Without being received, it is possible to appropriately determine the presence or absence of a received signal and perform a channel search.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent No. 3005475

  However, since the conventional receiver 1 is equipped with the temperature sensor 8, there is a problem that the circuit scale becomes large.

  Therefore, an object of the present invention is to reduce the circuit scale in a receiving apparatus that performs control in consideration of the influence of ambient temperature.

  In order to achieve the above object, a receiving apparatus of the present invention includes a MEMS vibrator that outputs a reference signal, an oscillator that outputs an oscillation signal based on the reference signal output from the MEMS vibrator, and an output from the oscillator. A mixer to which the oscillation signal is input, an amplifier connected to the input side or output side of the mixer, a signal intensity detection unit connected to the output side of the amplifier to detect reception intensity, and the mixer And a control unit for controlling the amplification degree of the amplifying unit based on the detection result of the signal intensity detecting unit.

  The control unit detects the ambient temperature based on the frequency variation detected by the frequency variation detection unit, and performs control to determine the presence or absence of a received signal based on the detected temperature and the detection result of the signal intensity detection unit.

  Since the receiving apparatus of the present invention performs control in consideration of the influence of the ambient temperature without using a temperature sensor, the circuit scale can be reduced.

(Embodiment 1)
Hereinafter, the receiving apparatus according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a block diagram of an electronic device in which the receiving device 9 according to the first embodiment is mounted.

  In FIG. 1, a receiving device 9 is formed in, for example, the same semiconductor IC, and is connected to the output side of the antenna 10 to remove unnecessary signals and is connected to the output side of the filter 11, for example, including a band limiting filter. And a mixer 13 connected to the output side of the amplifier 12 for mixing the received signal and the oscillation signal. The receiving device 9 includes a MEMS (Micro Electro Mechanical Systems) vibrator 14 that outputs a reference signal, and an oscillator 15 that outputs an oscillation signal to the mixer 13 based on the reference signal output from the MEMS vibrator 14. Prepare. Furthermore, the receiving device 9 includes an AD conversion unit 16 that is connected to the output side of the mixer 13 and converts an analog signal into a digital signal, and a demodulation processing unit 17 that is connected to the output side of the AD conversion unit 16. . Furthermore, the receiving device 9 is connected between the AD conversion unit 16 and the demodulation processing unit 17 and connected between the signal strength detection unit 18 that detects the reception strength, and between the AD conversion unit 16 and the demodulation processing unit 17. And a control unit 20 that controls the amplification degree of the amplifying unit 12 based on the detection result of the signal intensity detecting unit 18.

  An electronic device (not shown) equipped with the receiving device 9 includes a decoding processing unit 22 connected to the output side of the receiving device 9 and a display unit 23 connected to the output side of the decoding processing unit 22. Have.

  The control unit 20 detects the ambient temperature based on the frequency variation detected by the frequency variation detection unit 19, and performs control to determine the presence / absence of a received signal based on the detected temperature and the detection result of the signal intensity detection unit 18.

  Next, the control of the control unit 20 will be described in detail.

  The amplification degree of the amplification unit 12 varies depending on the ambient temperature of the amplification unit 12. Therefore, when performing a channel search, the control unit 20 needs to determine the presence / absence of a signal in consideration of a variation in the amplification degree of the amplification unit 12 due to the ambient temperature.

  Here, in the MEMS vibrator 14, the frequency fluctuation of the output reference signal significantly occurs depending on the ambient temperature of the MEMS vibrator 14. The control unit 20 performs temperature detection using the fluctuation of the intermediate frequency that is generated due to the fluctuation of the frequency of the reference signal. That is, the control unit 20 detects the ambient temperature based on the table shown in (Table 1) stored in the storage unit 21 connected to the control unit 20.

  This (Table 1) shows the relationship between the frequency fluctuation detected by the frequency fluctuation detector 19, the ambient temperature of the amplifier 12, and a threshold correction value for determining the presence or absence of a signal.

  For example, when the ambient temperature of the reception device 9 is room temperature (20 ° C.), the reception intensity threshold when the control unit 20 determines the presence / absence of a signal is −90 dBm.

  First, the frequency fluctuation detecting unit 19 compares the set reception frequency, that is, the frequency when the ambient temperature is room temperature (20 ° C.) with the frequency of the actual input signal, and the frequency fluctuation value that is the difference between these frequencies. Is −0.311 MHz, the control unit 20 determines that the ambient temperature is 60 ° C. Then, the control unit 20 refers to the table (Table 1) stored in the storage unit 21 and reads that the correction value is −1.6 dB when the ambient temperature of the amplification unit 12 is 60 ° C. The unit 20 determines the presence / absence of a reception signal by setting the reception intensity threshold value to −91.6 dBm (= −90 dBm−1.6 dB). In this way, the receiving device 9 performs a channel search.

  Thereby, even if the amplification degree of the amplifying unit 12 varies depending on the ambient temperature, the control unit 20 determines the presence / absence of the received signal based on the determination criterion derived from the detection result of the frequency variation detecting unit 19. The channel search can be performed by appropriately determining the presence / absence of the received signal without receiving much. That is, the control unit 20 can accurately determine the presence / absence of a received signal only because the temperature is detected using the MEMS vibrator 14 using a silicon material having a linear frequency variation with respect to temperature instead of the conventional crystal vibrator. . Thus, since the receiving device 9 performs control in consideration of the influence of the ambient temperature without using a temperature sensor, the circuit scale can be reduced.

(Embodiment 2)
Hereinafter, the receiving apparatus according to the second embodiment will be described with reference to FIG. FIG. 1 is a block diagram of an electronic device on which the receiving device 9 according to the second embodiment is mounted. Unless otherwise specified, the receiving apparatus according to the second embodiment has the same configuration as that of the first embodiment.

  In FIG. 1, a receiving device 9 is formed in, for example, the same semiconductor IC, and is connected to the output side of the antenna 10 to remove unnecessary signals and is connected to the output side of the filter 11, for example, including a band limiting filter. And a mixer 13 connected to the output side of the amplifier 12 for mixing the received signal and the oscillation signal. The receiving device 9 includes a MEMS vibrator 14 that outputs a reference signal, and an oscillator 15 that outputs an oscillation signal to the mixer 13 based on the reference signal output from the MEMS vibrator 14. Furthermore, the receiving device 9 includes an AD conversion unit 16 that is connected to the output side of the mixer 13 and converts an analog signal into a digital signal, and a demodulation processing unit 17 that is connected to the output side of the AD conversion unit 16. . Furthermore, the receiving device 9 is connected between the AD conversion unit 16 and the demodulation processing unit 17 and connected between the signal strength detection unit 18 that detects the reception strength, and between the AD conversion unit 16 and the demodulation processing unit 17. And a control unit 20 that controls the amplification degree of the amplifying unit 12 based on the detection result of the signal intensity detecting unit 18.

  This control unit detects the temperature of the MEMS vibrator 14 based on the frequency variation detected by the frequency variation detection unit, and controls the amplification degree of the amplification unit 12 based on the detected temperature.

  The amplification degree of the amplification unit 12 varies depending on the ambient temperature of the amplification unit 12. Therefore, the control unit 20 needs to control the amplification degree of the amplification unit 12 in consideration of the fluctuation in amplification degree of the amplification unit 12 due to the ambient temperature.

  Thereby, even if the amplification degree of the amplification unit 12 varies depending on the ambient temperature, the control unit 20 controls the amplification degree of the amplification unit 12 based on the ambient temperature derived from the detection result of the frequency variation detection unit 19. The amplification degree can be controlled without being affected by the ambient temperature. That is, the control unit 20 accurately executes the amplification degree control because the temperature detection is performed by using the MEMS vibrator 14 using a silicon material having a linear frequency variation with respect to the temperature instead of the conventional crystal vibrator. Can do. Thus, since the receiving device 9 performs control in consideration of the influence of the ambient temperature without using a temperature sensor, the circuit scale can be reduced.

(Embodiment 3)
Hereinafter, the receiving apparatus according to the third embodiment will be described with reference to FIG. FIG. 2 is a block diagram of an electronic device equipped with the receiving device 9 according to the third embodiment. Unless otherwise specified, the receiving apparatus according to the third embodiment has the same configuration as that of the first or second embodiment.

  In FIG. 2, the receiving device 9 further includes a clock unit 30 connected to the control unit 20.

  The control unit 20 detects the ambient temperature based on the frequency variation detected by the frequency variation detection unit 19, and performs control to determine the presence / absence of a received signal based on the detected temperature and the detection result of the signal intensity detection unit 18.

  When the power of the receiving device 9 is turned on, the temperature of the receiving device 9 immediately after the power is turned on is different from the temperature of the receiving device 9 when a predetermined time has elapsed after the power is turned on. Note that they are particularly different in a cold state where the ambient temperature of the receiving device 9 is 20 degrees below freezing.

  As a result, the signal strength immediately after turning on the power of the receiving device 9 and the signal strength that becomes substantially constant after a predetermined time has passed since the power of the receiving device 9 is turned on are, for example, the signal strength received by the antenna 10. Even if it is the same, it will be different. This is because the amplification degree of the amplification unit 12 is different in each case. Therefore, the control unit 20 detects the temperature of the MEMS vibrator based on the frequency fluctuation detected by the frequency fluctuation detection unit 19 after a predetermined time has elapsed since the receiving device 9 was turned on based on the time measurement result of the clock unit 30. The detection result of the signal intensity detection unit 18 is corrected.

  Next, the control of the control unit 20 will be described in detail.

  When the power is turned on, the clock unit 30 starts measuring time. Next, the control unit 20 acquires the time from the clock unit 30 when performing channel search or field strength acquisition. Next, the control unit 20 acquires a predetermined time recorded in advance in the storage unit 21 and compares the predetermined time with the time acquired from the clock unit 30. As a result of this comparison, when the time acquired from the clock unit 30 has exceeded the predetermined time acquired from the storage unit 21, the control unit 20 performs the same received signal determination as in the first embodiment.

  In addition, as a result of comparison, when the time acquired from the clock unit 30 has not passed the predetermined time acquired from the storage unit 21, the control unit 20 stores the storage unit in advance on the detection value detected by the signal strength detection unit 18. A value obtained by correcting the correction value recorded in 21 is used as a detection value.

  The presence / absence of a received signal is determined by the same operation as in the first embodiment.

  As described above, the control unit 20 detects the temperature of the MEMS vibrator 14 based on the frequency variation detected by the frequency variation detection unit 19 after a predetermined time has elapsed since the power of the receiving device 9 is turned on, and thus adjusts the frequency during the temperature variation. The power consumption of the receiving device 9 can be reduced.

  In the third embodiment, the control unit 20 detects the temperature of the MEMS vibrator 14 based on the frequency variation detected by the frequency variation detection unit 19 as in the second embodiment, and the amplification unit 12 based on the detected temperature. The degree of amplification may be controlled. Also in this case, since the control unit 20 detects the temperature of the MEMS vibrator 14 based on the frequency fluctuation detected by the frequency fluctuation detection unit after a lapse of a predetermined time after the power of the receiving device 9 is turned on, the temperature can be detected more accurately. It can be done.

  The receiving device according to the present invention can be reduced in circuit scale and can be used for electronic devices such as mobile phones.

The block diagram of the receiver in Embodiment 1, 2 of this invention The block diagram of the receiver in Embodiment 3 of this invention Block diagram of conventional receiver

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 Receiving device 10 Antenna 11 Filter 12 Amplifier 13 Mixer 14 MEMS vibrator 15 Oscillator 16 AD conversion part 17 Demodulation processing part 18 Signal strength detection part 19 Frequency fluctuation detection part 20 Control part 21 Storage part 22 Decoding processing part 23 Display part 30 Clock

Claims (5)

A MEMS vibrator that outputs a reference signal;
An oscillator that outputs an oscillation signal based on a reference signal output by the MEMS vibrator;
A mixer to which the oscillation signal output from the oscillator is input;
An amplifier connected to the input side or output side of the mixer;
A signal strength detector connected to the output side of the amplifier to detect the received strength;
A frequency fluctuation detector connected to the output side of the mixer to detect a frequency fluctuation of the input signal;
A control unit for controlling the amplification degree of the amplification unit based on the detection result of the signal intensity detection unit,
The control unit detects a surrounding temperature based on the frequency variation detected by the frequency variation detection unit, and determines whether or not there is a reception signal based on the detected temperature and a detection result of the signal intensity detection unit. A MEMS vibrator that outputs a reference signal;
An oscillator that outputs an oscillation signal based on a reference signal output by the MEMS vibrator;
A mixer to which the oscillation signal output from the oscillator is input;
An amplifier connected to the input side or output side of the mixer;
A signal strength detector connected to the output side of the amplifier to detect the received strength;
A frequency fluctuation detector connected to the output side of the mixer to detect a frequency fluctuation of the input signal;
A control unit for controlling the amplification degree of the amplification unit based on the detection result of the signal intensity detection unit,
The control unit detects a temperature of the MEMS vibrator based on a frequency variation detected by the frequency variation detection unit, and controls the amplification degree of the amplification unit based on the detected temperature. The receiving apparatus according to claim 1, wherein at least the MEMS vibrator, the oscillator, the mixer, and the amplifier are formed on the same semiconductor substrate. The receiving device according to claim 1, wherein the control unit detects the temperature of the MEMS vibrator based on a frequency fluctuation detected by the frequency fluctuation detecting unit after a predetermined time has elapsed since the power of the receiving device is turned on. The receiving device according to claim 1 or 2,
An electronic apparatus including a display unit connected to the output side of the receiving device.