JP5625797B2 - Temperature correction circuit, demodulation circuit, communication device, temperature correction method, and demodulation method - Google Patents

Description

  The present invention relates to a temperature correction circuit, a demodulation circuit, a communication device, a temperature correction method, and a demodulation method that compensate for temperature characteristics of an analog circuit.

  In general, an analog circuit has a characteristic that circuit characteristics become unstable due to a temperature change. For example, an analog circuit included in the demodulation circuit of the communication apparatus amplifies the received signal with a predetermined gain and demodulates the amplified received signal. For this reason, in a demodulation circuit or the like, a gain variation of the analog circuit occurs due to a temperature change, and an error occurs in the output signal.

  As a technique for adjusting the gain fluctuation, a technique called IF AGC (Intermediate Frequency Automatic Gain Control) that adjusts the gain of the analog circuit according to the level of the received signal is used. The demodulation circuit using IF AGC has a gain so as to make the level of the output signal constant by feeding back the control value to the intermediate frequency amplifier circuit while changing the control value based on the output value of the intermediate frequency amplifier circuit. adjust.

  As another technique for adjusting gain fluctuation, an apparatus having a temperature correction circuit that suppresses gain fluctuation due to temperature change is known (for example, see Patent Document 1).

  The apparatus described in Patent Document 1 acquires ambient atmosphere temperature data detected by a temperature sensor. The apparatus reads temperature correction data corresponding to the acquired ambient atmosphere temperature data from temperature correction information recorded in advance in a ROM (Read Only Memory). Further, this apparatus generates a gain control signal based on the read temperature correction data. The apparatus then adjusts the gain by providing the generated gain control signal to the amplifier.

JP 2009-186406 A

  However, the demodulation circuit using IF AGC regards an error based on a gain variation due to a temperature change in the analog circuit as a variation in the level value of the input signal. For this reason, a demodulation circuit using IF AGC may generate different control values for the same level of input signals when gain fluctuations due to temperature changes in the analog circuit occur, and perform appropriate gain adjustment. I can't.

  Further, the temperature characteristics of the analog circuit vary depending on the device. However, the apparatus described in Patent Document 1 does not consider such individual differences, and may not be able to perform appropriate gain adjustment.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a demodulation circuit and a temperature correction circuit that can compensate for a gain variation of an analog circuit due to a temperature change with higher accuracy.

  The temperature correction circuit of the present invention includes a temperature acquisition unit that acquires an ambient temperature around a predetermined analog circuit unit, and a temperature correction that stores temperature correction data that compensates for gain fluctuations in the analog circuit unit due to a change in the ambient temperature. A data storage unit, an individual difference correction data storage unit that stores individual difference correction data that compensates for individual differences in gain fluctuations of the analog circuit unit accompanying changes in the ambient temperature, and an ambient temperature acquired by the temperature acquisition unit And a correction unit that outputs a signal in which a variation due to a temperature change in the level of the output signal of the analog circuit unit is corrected based on the temperature correction data and the individual difference correction data according to.

  The demodulation circuit of the present invention includes the temperature correction circuit of the present invention, the analog circuit unit, an amplification unit that amplifies a reception signal, and the reception circuit that is included in the analog circuit unit and amplified by the amplification unit. And a demodulator that demodulates the signal.

  The communication device of the present invention also includes the demodulation circuit of the present invention that demodulates the received signal and outputs a baseband received signal.

  Further, the temperature correction method of the present invention includes a temperature acquisition step for acquiring an ambient temperature around a predetermined analog circuit unit, and a temperature for compensating for a gain variation of the analog circuit unit due to a change in the ambient temperature around the analog circuit unit. From a temperature correction data storage unit in which correction data is stored in advance and an individual difference correction data storage unit in which individual difference correction data for compensating for individual differences in gain fluctuations in the analog circuit unit due to changes in the ambient temperature are stored in advance. The temperature correction data and the individual difference correction data corresponding to the ambient temperature acquired in the temperature acquisition step are acquired, and an output signal from the analog circuit unit based on the acquired temperature correction data and the individual difference correction data And a correction step for outputting a signal obtained by correcting a variation due to a temperature change of the level of the above.

  The demodulation method of the present invention includes an amplification step of amplifying a received signal using an analog circuit unit, a demodulation step of demodulating the amplified received signal using the analog circuit unit, and an ambient temperature around the analog circuit unit A temperature acquisition step for acquiring the temperature correction data, a temperature correction data storage unit that preliminarily stores temperature correction data that compensates for a gain variation of the analog circuit unit accompanying a change in the ambient temperature around the analog circuit unit, and a change in the ambient temperature From the individual difference correction data storage unit in which individual difference correction data for compensating for individual differences in gain fluctuation of the analog circuit unit is stored in advance, the temperature correction data according to the ambient temperature acquired in the temperature acquisition step, and the Acquire individual difference correction data, based on the acquired temperature correction data and the individual difference correction data , And a correction step of outputting the corrected signal variation due to temperature change in the level of the output signal of said demodulating step.

  The present invention can provide a temperature correction circuit capable of compensating the gain fluctuation of the analog circuit section due to temperature change with higher accuracy.

It is a block diagram of the temperature correction circuit as the 1st Embodiment of this invention. It is a figure which shows an example of the temperature characteristic of the analog circuit in the 1st Embodiment of this invention. It is a figure which shows an example of the temperature correction data in the 1st Embodiment of this invention. It is a figure which shows another example of the temperature correction data in the 1st Embodiment of this invention. It is a block diagram of the demodulation circuit as the 2nd Embodiment of this invention. It is a block diagram of the demodulation circuit as the 3rd Embodiment of this invention. It is a figure which shows the circuit structural example of the demodulation circuit as the 3rd Embodiment of this invention. It is a figure which shows the circuit structural example of the temperature correction circuit in the 3rd Embodiment of this invention. It is a figure which shows the circuit structural example of the individual difference correction data generation circuit in the 3rd Embodiment of this invention. It is a block diagram of the communication apparatus as the 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows the configuration of a temperature correction circuit 1 as a first embodiment of the present invention.

  In FIG. 1, the temperature correction circuit 1 includes a temperature acquisition unit 11, a temperature correction data storage unit 12, an individual difference correction data storage unit 13, and a correction unit 14. The temperature correction circuit 1 is connected to a predetermined analog circuit unit 20 and acquires an output signal from the analog circuit unit 20 as an input signal.

  The temperature acquisition unit 11 acquires the ambient temperature around a predetermined analog circuit unit. For example, the temperature acquisition unit 11 acquires a voltage value output from a temperature sensor provided around a predetermined analog circuit unit as a temperature detection signal. The temperature acquisition unit 11 is configured by, for example, a CPU (Central Processing Unit), and operates by reading and executing a computer program stored in a storage device such as a ROM.

  The temperature correction data storage unit 12 stores in advance temperature correction data that compensates for gain fluctuations in the analog circuit unit 20 due to changes in the ambient temperature. The temperature correction data storage unit 12 is configured by a ROM, for example.

  Here, the temperature correction data will be described. In general, in an analog circuit, the gain decreases as the temperature increases. For this reason, the analog circuit part 20 has a temperature characteristic as shown in FIG. 2, for example. An example of temperature correction data for compensating for the temperature characteristics of FIG. 2 is shown in FIG.

  As shown in FIG. 3, the temperature correction data may be a difference between a gain at an arbitrary temperature and a gain at a predetermined normal temperature (for example, 25 degrees Celsius) in the temperature characteristics of FIG. That is, the temperature correction data corresponds to the inverse characteristic of the temperature characteristic of the analog circuit unit.

  The temperature correction data may be data representing an approximate expression in which the inverse characteristic of the temperature characteristic of the analog circuit unit is approximated by a linear expression or the like.

  Another example of the temperature correction data is shown in FIG. As shown in FIG. 4, for example, the temperature correction data is X decibel (hereinafter referred to as [dB]) at 30 degrees Celsius or more and less than 40 degrees Celsius, and Y [dB] correction is performed at 40 degrees Celsius or more and less than 50 degrees Celsius. As described above, a certain value may be determined for the temperature range.

  The individual difference correction data storage unit 13 stores in advance individual difference correction data that compensates for individual differences in gain variation of the analog circuit unit 20 due to changes in the ambient temperature. The individual difference correction data storage unit 13 is configured by, for example, a ROM.

  Here, the individual difference correction data is for correcting the deviation of the temperature characteristics of each analog circuit unit 20 for each individual. For example, the individual difference correction data may be a difference between a gain correction value at an arbitrary ambient temperature of the analog circuit unit 20 detected for each individual and the temperature correction data stored in the temperature correction data storage unit 12. Good. In addition, as the individual difference correction data, correction data may be set for an arbitrary atmospheric temperature. Alternatively, the individual difference correction data may be data representing an approximate expression in which the correction value for the ambient temperature is approximated by a linear expression or the like. Alternatively, the individual difference correction data may have a fixed value with respect to the temperature range. The individual difference correction data is stored by being detected for each individual when the analog circuit unit 20 is inspected.

  The correction unit 14 acquires temperature correction data and individual difference correction data corresponding to the ambient temperature acquired by the temperature acquisition unit 11 from the temperature correction data storage unit 12 and the individual difference correction data storage unit 13.

  For example, when the temperature correction data storage unit 12 and the individual difference correction data storage unit 13 store data representing an approximate expression of a correction value for the atmospheric temperature, the correction unit 14 uses the acquired atmospheric temperature as an approximate expression. By applying, corresponding temperature correction data and individual difference correction data may be calculated.

  Alternatively, when constant correction data is stored in the temperature correction data storage unit 12 and the individual difference correction data storage unit 13 with respect to a temperature range of a predetermined width, the correction unit 14 includes the detected ambient temperature. Temperature correction data and individual difference correction data associated with the temperature range to be acquired may be acquired.

  Alternatively, when the correction data is stored in the temperature correction data storage unit 12 and the individual difference correction data storage unit 13 in association with the arbitrary atmospheric temperature, the correction unit 14 selects the individual corresponding to the acquired atmospheric temperature. The difference correction data may be estimated using a linear interpolation method or the like.

  Then, the correction unit 14 outputs a signal obtained by correcting a variation due to a temperature change in the level of the output signal of the analog circuit unit 20 based on the acquired temperature correction data and individual difference correction data. For example, the correction unit 14 outputs a signal obtained by multiplying the output signal of the analog circuit unit 20 by temperature correction data and individual difference correction data.

  At this time, when the output signal of the analog circuit unit 20 is handled as a decibel value, and the temperature correction data and the individual difference correction data are stored as the decibel value, the correction unit 14 uses the output signal of the analog circuit unit 20 as an output signal. The correction signal may be output by adding the temperature correction data and the individual difference correction data.

  The correction unit 14 is configured by a CPU, for example, and operates by reading and executing a computer program stored in a storage device such as a ROM.

  The operation of the temperature correction circuit 1 configured as described above will be described.

  First, the correction unit 14 acquires an output signal from the analog circuit unit 20 as an input signal. At this time, the output signal from the analog circuit unit 20 may be affected by a gain variation due to a change in ambient temperature around the analog circuit unit 20. Next, the temperature acquisition unit 11 acquires the ambient temperature around the analog circuit unit 20. Next, the correction unit 14 acquires temperature correction data and individual difference correction data corresponding to the acquired ambient temperature from the temperature correction data storage unit 12 and the individual difference correction data storage unit 13. Then, the correction unit 14 outputs a signal in which a variation due to a temperature change in the level of the output signal from the analog circuit unit 20 is corrected based on the acquired temperature correction data and individual difference correction data. Specifically, for example, the correction unit 14 performs correction by adding the decibel value of the temperature correction data and the individual difference correction data to the decibel value of the output signal from the analog circuit unit 20.

  Above, description of operation | movement of the temperature correction circuit 1 is complete | finished.

  Next, effects of the first exemplary embodiment of the present invention will be described.

  The temperature correction circuit according to the first embodiment of the present invention can compensate the gain fluctuation due to the temperature change of the analog circuit section with higher accuracy.

  The reason is that, in addition to the temperature correction data storage unit storing temperature correction data that compensates for the temperature characteristics of the analog circuit unit, the individual difference correction data storage unit is configured to detect individual differences in the temperature characteristics of the analog circuit unit. This is because individual difference correction data for compensating for is stored in advance. This is because the correction unit corrects the level of the output signal from the analog circuit unit using the temperature correction data in consideration of the individual difference correction data.

(Second Embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that, in each drawing referred to in the description of the present embodiment, the same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and detailed description thereof will be omitted.

  FIG. 5 shows the configuration of the demodulation circuit 2 as the second embodiment of the present invention.

  In FIG. 5, the demodulation circuit 2 includes an amplification unit 21, a demodulation unit 22, a temperature detection unit 23, and a temperature correction circuit 1 as the first embodiment of the present invention. The demodulation circuit 2 is provided in a communication device that receives a reception signal via an antenna or the like.

  The amplifying unit 21 is included in the analog circuit unit 20. In addition, the amplification unit 21 amplifies the reception signal received by the communication device provided with the demodulation circuit 2 with a predetermined gain so that the reception signal can be demodulated by the demodulation unit 22.

  The demodulation unit 22 is included in the analog circuit unit 20. The demodulation unit 22 demodulates the reception signal amplified by the amplification unit 21. For example, the demodulator 22 is configured by an orthogonal demodulator or the like. Note that the demodulation method of the demodulator employed in the demodulator 22 is in accordance with the modulation method on the transmission side.

  The signal demodulated by the demodulator 22 is converted to a digital signal by an A / D (Analog to Digital) converter and output to the temperature correction circuit 1.

  The temperature detection unit 23 detects the ambient temperature around the analog circuit unit 20. For example, the temperature detection unit 23 includes a thermistor, and outputs a voltage value that changes according to the ambient temperature to the temperature acquisition unit 11 of the temperature correction circuit 1 as a temperature detection signal.

  The operation of the demodulation circuit 2 configured as described above will be described.

  First, the reception signal is input to the amplification unit 21. Then, the amplification unit 21 amplifies the reception signal with a predetermined gain. Next, the demodulator 22 demodulates the received signal amplified by the amplifier 21. At this time, there is a possibility that the output signal from the demodulating unit 22 is affected by the gain fluctuation of the analog circuit unit 20 due to the change in the ambient temperature. Next, the temperature detection unit 23 detects the ambient temperature around the analog circuit unit 20. Next, the temperature acquisition unit 11 acquires the detected ambient temperature. Next, the correction unit 14 acquires temperature correction data and individual difference correction data corresponding to the detected ambient temperature from the temperature correction data storage unit 12 and the individual difference correction data storage unit 13. Then, the correction unit 14 outputs a signal obtained by correcting the variation due to the temperature change of the level of the output signal from the demodulation unit 22 based on the acquired temperature correction data and individual difference correction data. Specifically, for example, the correction unit 14 performs correction by adding the decibel value of the temperature correction data and the individual difference correction data to the decibel value of the output signal from the demodulation unit 22.

  Above, description of operation | movement of the demodulation circuit 2 is complete | finished.

  Next, the effect of the second exemplary embodiment of the present invention will be described.

  The demodulating circuit according to the second embodiment of the present invention can output a demodulated signal in which the gain fluctuation of the analog circuit due to temperature change is compensated with higher accuracy.

  The reason is that the temperature correction data storage unit stores the temperature correction data for compensating the temperature characteristics of the analog circuit including the amplification unit and the demodulation unit, and the individual difference correction data storage unit This is because individual difference correction data for compensating for individual differences is stored in advance, and the correction unit corrects the demodulated signal using temperature correction data taking into account the individual difference correction data.

(Third embodiment)
Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Note that in each drawing referred to in the description of the present embodiment, the same components as those in the second embodiment of the present invention are denoted by the same reference numerals, and detailed description thereof will be omitted.

  FIG. 6 shows the configuration of a demodulation circuit 3 as a third embodiment of the present invention.

  In FIG. 6, the demodulation circuit 3 further includes a gain control signal generation unit 34 with respect to the demodulation circuit 2 as the second embodiment of the present invention, and an amplification unit 31 instead of the amplification unit 21 and a temperature correction The difference is that a temperature correction circuit 4 is provided instead of the circuit 1. The temperature correction circuit 4 is different from the temperature correction circuit 1 according to the first embodiment of the present invention in that an individual difference correction data storage unit 43 is provided instead of the individual difference correction data storage unit 13.

  The amplifying unit 31 is configured by an amplifier having a function of adjusting a gain based on a gain control signal input from the outside.

  The gain control signal generation unit 34 generates a gain control signal for the amplification unit 31 based on the output signal from the correction unit 14. This gain control signal is a signal for controlling the gain so that the level of the output signal from the correction unit 14 becomes substantially constant according to the level fluctuation of the reception signal input to the analog circuit unit 20.

  The individual difference correction data storage unit 43 stores data for correcting fluctuations in the gain control signal accompanying changes in the atmospheric temperature as individual difference correction data.

  This individual difference correction data is detected by changing the ambient temperature while the power of the reception signal input to the demodulation circuit 3 is kept constant, for example, when the demodulation circuit 3 is inspected. For example, the individual difference correction data may be generated based on a difference between a gain control signal generated at a predetermined normal temperature and a gain control signal generated at an arbitrary ambient temperature.

  FIG. 7 shows a circuit configuration example in the case where a quadrature demodulator is employed in the demodulator 22 in the demodulator circuit 3 of the present embodiment. 7 receives an IF reception signal converted from an RF (Radio Frequency) band to an IF (Intermediate Frequency) band, and outputs a BB (Baseband) reception signal obtained by demodulating the IF reception signal. . The circuit configuration example of the demodulation circuit in the present invention is not limited to the following.

  In FIG. 7, the demodulation circuit 3 includes a BPF (Band Pass Filter) 301 and a VGA (Variable Gain Amplifier) 302 as analog circuits. The demodulating circuit 3 further includes an LO (Local Oscillator) 303, a π / 2 phase converter 304, quadrature demodulators 305 and 306, and LPFs (Low Pass Filters) 307, 308, and 317 as analog circuits. Is included.

  The demodulating circuit 3 further includes A / D converters 309 and 310, and converts the output from the analog circuit into a digital signal. Here, it is assumed that the digital signal after A / D conversion is handled as a decibel value.

  Further, the demodulating circuit 3 includes, as digital circuits, a temperature correction circuit 4, an IF AGC control circuit 312, FIR (Finite Impulse Response) filters 313 and 314, an EQL (Equalizer) 315, and a PD (PH DET, phase comparison). 316).

  Here, the amplifying unit 31 is configured by a VGA 302. The demodulator 22 includes an LO 303, a π / 2 phase converter 304, quadrature demodulators 305 and 306, and LPFs 307 and 308.

  The BPF 301 removes signals other than a predetermined IF band.

  The VGA 302 is configured using an amplifier whose gain changes in accordance with an external control signal. The gain of the VGA 302 is variable by increasing or decreasing the voltage value of the IF AGC control signal output from the IF AGC control circuit 312.

  The LO 303 generates a signal for downconverting the IF band signal to the baseband band.

  The π / 2 phase converter 304 performs π / 2 conversion on the phase of the LO 303 and inputs the result to the quadrature demodulator 305.

  The quadrature demodulator 305 extracts the in-phase component Pch by multiplying the output signal of the VGA 302 by the output signal of the LO 303 subjected to π / 2 phase conversion.

  The quadrature demodulator 306 multiplies the output signal of the VGA 302 and the output signal of the LO 303 to extract the quadrature component Qch.

  LPFs 307 and 308 block signals having a predetermined frequency or higher from the output signals of quadrature demodulators 305 and 306.

  The FIR filters 313 and 314 shape the waveform of the signal output from the temperature correction circuit 4.

  The EQL 315 removes the influence of intersymbol interference and the like.

  The PD 316 extracts the phase difference between the transmission side frequency and the LO 303.

  The LPF 317 suppresses the noise component by integrating the PD signal.

  The IF AGC control circuit 312 is a multiplier for calculating the power of output signals from the A / D converters 309 and 310, a memory for storing desired power information (reference), and comparing the output signal of the A / D converter with the reference. Have a comparator or the like.

  The IF AGC control circuit 312 outputs an IF AGC control value for making the output level from the A / D converters 309 and 310 substantially constant to the VGA 302. That is, the IF AGC control circuit 312 increases or decreases the IF AGC control value output to the VGA 302 based on the comparison result by the comparator.

  The IF AGC control circuit 312 also outputs this IF AGC control value to the temperature correction circuit 4.

  Next, a configuration example of the temperature correction circuit 4 will be described with reference to FIGS.

  In FIG. 8, the temperature correction circuit 4 includes a ROM 401, a ROM 402, an individual difference correction data generation circuit 403, a CPU 404, and adders 405 and 406. The configuration of the individual difference correction data generation circuit 403 is shown in FIG. In FIG. 9, the individual difference correction data generation circuit 403 includes a selector 407, a calculation unit 408, and a VGA 409.

  Here, the temperature correction data storage unit 12 is configured by the ROM 401. The individual difference correction data storage unit 43 includes an individual difference correction data generation circuit 403 and a ROM 402. The temperature acquisition unit 11 and the correction unit 14 are configured by the CPU 404.

  In the ROM 401, temperature correction data similar to the temperature correction data in the first embodiment of the present invention described with reference to FIGS. 3 and 4 is stored in advance as a decibel value.

  The individual difference correction data generation circuit 403 acquires the ambient temperature detected by the temperature detection unit 23 and the IF AGC control value generated by the IF AGC control circuit 312 as input signals.

  The selector 407 outputs an input signal to the calculation unit 408 when individual difference correction data is generated, such as at the time of inspection of the apparatus, and switches to not output the input signal to the calculation unit 408 otherwise.

  The calculation unit 408 calculates a difference between the IF AGC control value at a predetermined reference temperature and the IF AGC control value output from the IF AGC control circuit 312 at an arbitrary ambient temperature (for example, a temperature change of 1 ° C. with respect to the reference temperature). The difference of IF AGC control value for ΔIF AGC / ° C.) is detected. In addition, the calculation unit 408 outputs the detected difference to the VGA 409.

  The VGA 409 converts the difference value (for example, ΔIF AGC / ° C.) of the IF AGC control value into a decibel value.

  The ROM 402 stores information output from the VGA 409. Here, the individual difference correction data stored in the ROM 402 may be associated with data corresponding to an arbitrary atmospheric temperature, or a certain value is associated with the temperature range. There may be.

  The individual difference correction data generation circuit 403 is a circuit that detects a difference at the time of inspection and stores the individual difference correction data in the ROM 402, and may be provided outside the demodulation circuit 3.

  The operation of the demodulation circuit 3 configured as described above will be described.

  First, an operation in which the individual difference correction data storage unit 43 stores individual difference correction data in advance will be described. This process is executed while changing the ambient temperature with the power of the reception signal input to the demodulation circuit 3 being constant.

  First, the calculation unit 408 of the individual difference correction data generation circuit 403 temporarily stores the IF AGC control value output from the AGC control circuit 24 at a predetermined reference temperature. Then, the calculation unit 408 calculates the difference between the IF AGC control value output from the AGC control circuit 24 according to the change in the ambient temperature and the IF AGC control value at the temporarily stored reference temperature. The VGA 409 converts the difference value into decibel value correction data. Then, the calculation unit 408 stores the ambient temperature detected by the temperature detection unit 23 and the correction data in the ROM 402 in association with each other.

  Next, an operation in which the temperature correction circuit 4 compensates for temperature characteristics when the demodulation signal 3 is demodulated by the demodulation circuit 3 will be described.

  First, the CPU 404 reads temperature correction data corresponding to the ambient temperature detected by the temperature detection unit 23 from the ROM 401.

  Next, the CPU 404 reads individual difference correction data corresponding to the ambient temperature detected by the temperature detection unit 23 from the ROM 402.

  Next, the CPU 404 outputs correction data obtained by adding the read temperature correction data and individual difference correction data to the adders 405 and 406.

  Next, adder 405 adds the output signal from A / D converter 309 of the in-phase component Pch and the correction data, and outputs the result to FIR filter 313 and IF AGC control circuit 312.

  Adder 406 adds the output signal from quadrature component Qch A / D converter 310 and the correction data, and outputs the result to FIR filter 314 and IF AGC control circuit 312.

  Above, description of operation | movement of the temperature correction circuit 4 is complete | finished.

  The demodulating circuit 3 may be provided with a selector between the ROM 402 and the CPU 404, and may be provided with a high accuracy mode in which individual difference correction data is applied and a normal mode in which it is not applied.

  Next, effects of the third exemplary embodiment of the present invention will be described.

  A demodulating circuit according to a third embodiment of the present invention is a demodulating circuit having a function of adjusting a gain so as to make the level of an output signal substantially constant according to the level of a received signal. Can be compensated with higher accuracy.

  The reason is that the individual difference correction data storage unit stores in advance, as individual difference correction data, data for correcting fluctuations in the gain control signal accompanying a temperature change when the input signal level is the same. Here, the gain control signal is generated based on the output signal after the influence due to the temperature change has already been corrected based on the temperature correction data common to the amplifiers. Therefore, the fluctuation of the gain control signal accompanying the temperature change when the level of the input signal is the same can be regarded as being based on the difference due to the individual difference in the temperature characteristic of the amplifier. This is because the demodulating circuit according to the third embodiment of the present invention does not regard the gain fluctuation due to the individual difference of the temperature characteristic of the amplifying part as the fluctuation of the level of the input signal.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  FIG. 10 shows the configuration of the communication device 5 as the fourth embodiment of the present invention. In FIG. 10, the communication device 5 includes a processing unit 51, a modulation circuit 52, a demodulation circuit 3, and a multiplexer 53, and is connected to an antenna 54.

  The processing unit 51 generates a baseband transmission signal by performing modulation processing based on QPSK (quadrature phase shift keying) and the like, error correction coding processing, and the like on transmission target data. The processing unit 51 also performs error correction code decoding processing, demodulation processing based on QPSK, and the like on the baseband received signal output from the demodulation circuit 3.

  The modulation circuit 52 modulates the baseband transmission signal output from the processing circuit 51 into the IF band.

  The demodulation circuit 3 is configured using the third embodiment of the present invention, and demodulates the IF reception signal into a baseband reception signal.

  The multiplexer 53 branches the IF transmission signal and the IF reception signal.

  The communication device 5 configured as described above operates as follows. First, the communication device 5 receives a received signal via the antenna 54 and converts the RF band to the IF band. Next, the demodulation circuit 3 operates on the IF band received signal in the same manner as in the third embodiment of the present invention to correct the gain variation due to the temperature change and demodulate the baseband received signal. . The processing circuit 51 performs error correction code decoding processing, demodulation processing based on QPSK, and the like on the corrected baseband reception signal.

  As described above, the communication device according to the fourth embodiment of the present invention includes the demodulation circuit according to the third embodiment of the present invention, thereby enabling communication due to the temperature characteristics of the analog circuit and the influence of individual differences thereof. Degradation can be suppressed with higher accuracy.

  It should be noted that the above-described embodiments can be implemented in combination as appropriate.

  The present invention is not limited to the above-described embodiments, and can be implemented in various modes.

1, 4 Temperature correction circuit 2, 3 Demodulation circuit 5 Communication device 11 Temperature acquisition unit 12 Temperature correction data storage unit 13, 43 Individual difference correction data storage unit 14 Correction unit 21, 31 Amplification unit 22 Demodulation unit 23 Temperature detection unit 34 Gain Control signal generation unit 51 processing unit 52 modulation circuit 53 multiplexer 54 antenna 301 BPF
302 VGA
303 LO
304 π / 2 phase converter 305, 306 Quadrature demodulator 307, 308, 317 LPF
309, 310 A / D converter 312 IF AGC control circuit 313, 314 FIR filter 315 EQL
316 PD
401, 402 ROM
403 Individual difference correction data generation circuit 404 CPU
405, 406 Adder 407 Selector 408 Calculation unit 409 VGA

Claims (5)

A temperature acquisition unit for acquiring an ambient temperature around a predetermined analog circuit unit;
A temperature correction data storage unit that stores temperature correction data that compensates for gain variations of the analog circuit unit due to changes in the ambient temperature;
The analog circuit based on the temperature correction data according to the ambient temperature acquired by the temperature acquisition unit and the individual difference correction data for compensating for individual differences in gain fluctuation of the analog circuit unit due to the change in the ambient temperature A correction unit that outputs a signal obtained by correcting a variation due to a temperature change in the level of the output signal of the unit;
A gain control signal generated by adjusting the gain of the analog circuit unit so as to make the level of the correction output signal substantially constant according to the level fluctuation of the received signal, and generated based on the output signal of the correction unit, An individual difference data storage unit for storing data generated based on a difference between a gain control signal generated at a predetermined normal temperature and a gain control signal generated at an arbitrary ambient temperature as the individual difference correction data; ,
Temperature correction circuit with A temperature correction circuit according to claim 1 ;
An amplification unit included in the analog circuit unit for amplifying a received signal;
A demodulator that is included in the analog circuit unit and demodulates the received signal amplified by the amplifier;
A demodulation circuit comprising: The communication apparatus comprising the demodulation circuit according to claim 2 , which demodulates the reception signal and outputs a baseband reception signal. It acquires predetermined analog circuitry ambient temperature around,
Storing temperature correction data that compensates for gain fluctuations in the analog circuit unit accompanying changes in ambient temperature around the analog circuit unit ;
Based on the temperature correction data and individual difference correction data that compensates for individual differences in gain fluctuations in the analog circuit unit due to changes in the ambient temperature, a variation due to a temperature change in the level of the output signal from the analog circuit unit Output the corrected signal and correct it ,
The gain of the analog circuit is adjusted so as to make the level of the output signal from the correction substantially constant in accordance with the level fluctuation of the input signal input to the analog circuit unit accompanying the change in the ambient temperature, and the correction A gain control signal generated based on the level of the output signal, the data generated based on the difference between the gain control signal generated at a predetermined normal temperature and the gain control signal generated at an arbitrary ambient temperature Is stored as the individual difference correction data. It amplifies the received signal by using an analog circuit portion,
The amplified received signal is demodulated using the analog circuit portion,
Gets the ambient temperature around the analog circuit portion,
Storing temperature correction data that compensates for gain fluctuations in the analog circuit unit accompanying changes in ambient temperature around the analog circuit unit ;
The temperature correction data and, on the basis of the individual difference correction data to compensate for the individual difference of the gain variation of the analog circuit portion due to a change in the ambient temperature, corrected for variation due to temperature change in the level of the output signal of the demodulator It corrected and outputs the signal,
A gain control signal that is generated based on the output signal of the correction, adjusting the gain of the analog circuit unit so that the level of the output signal of the correction is substantially constant according to the level fluctuation of the received signal, A demodulation method characterized by storing data generated based on a difference between a gain control signal generated at a predetermined normal temperature and a gain control signal generated at an arbitrary ambient temperature as the individual difference correction data .

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