JP4992614B2 - COMMUNICATION DEVICE, COMMUNICATION METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a communication device, a communication method, and a program, and more particularly to a communication device, a communication method, and a program that can control an amplification factor so that a received signal has an optimum amplitude.

  Conventionally, in a wireless LAN (Local Area Network), a communication device on the transmission side modulates a carrier wave of a predetermined frequency with a baseband signal that is a signal corresponding to data to be transmitted, and transmits the resulting modulated wave To do. On the other hand, the communication device on the reception side receives the modulated wave transmitted from the communication device on the transmission side, and acquires the baseband signal by demodulating the modulated wave.

  In the communication device on the receiving side, a baseband signal obtained by demodulating the modulated wave is amplified by an amplifier, and processing such as AD (Analog Digital) conversion is performed on the baseband signal amplified to a predetermined amplitude. Applied. For example, the communication device automatically sets the amplification factor of the amplifier so that the amplifier can output the baseband signal with a constant amplitude even when the reception intensity of the modulated wave received by the communication device fluctuates. An automatic gain control (AGC) circuit that adjusts automatically is provided.

  FIG. 1 is a block diagram illustrating a configuration of an example of a communication device including an AGC circuit.

  In FIG. 1, a communication device 11 includes an antenna 12, a BPF (Band Pass Filter) 13, an LNA (Low Noise Amplifier) 14, two mixer units 15 and 16, and two VGAs (Variable Gain). Amplifier: variable gain amplifier) 17 and 18, two BPFs 19 and 20, two ADCs (Analog Digital Converter) 21 and 22, digital filter 23, power integration processing circuit 24, RSSI (Received Signal Strength Indicator) The circuit 25 includes an AGC circuit 26 and a DAC (Digital Analog Converter) 27.

  The antenna 12 receives a modulated wave transmitted from a communication device (not shown) on the transmission side and supplies the modulated wave to the BPF 13. The BPF 13 filters the modulated wave supplied from the antenna 12 and supplies a modulated wave in a predetermined frequency band to the LNA 14. The LNA 14 amplifies the modulated wave supplied from the BPF 13 with low noise and supplies the amplified wave to the mixer units 15 and 16 and the RSSI circuit 25.

  The mixer units 15 and 16 demodulate the modulated wave by multiplying the modulated wave supplied from the LNA 14 with a signal of a predetermined frequency generated by an oscillator (not shown), and output a baseband signal.

  Here, it is assumed that QPSK (quadrature phase shift keying) is adopted as a modulation method for modulating a carrier wave. In QPSK, a baseband signal is transmitted by being divided into an I component in phase with a carrier wave and a Q component orthogonal to the carrier wave. For example, the mixer unit 15 outputs the I component of the baseband signal, and the mixer unit 16 Outputs the Q component of the baseband signal.

  The VGA 17 is supplied with the I component of the baseband signal from the mixer unit 15, and the VGA 17 amplifies the I component of the baseband signal with an amplification factor corresponding to a control signal (voltage) supplied from the DAC 27 as will be described later. Then, the signal obtained as a result is supplied to the BPF 19.

  The VGA 18 is supplied with the Q component of the baseband signal from the mixer unit 16, and the VGA 18 supplies a signal obtained by amplifying the Q component of the baseband signal to the BPF 20, similarly to the VGA 17.

  The BPF 19 filters the signal supplied from the VGA 17 and supplies a signal in a predetermined frequency band to the ADC 21. The BPF 20 filters the signal supplied from the VGA 18 and supplies a signal in a predetermined frequency band to the ADC 22. Here, the signals output by the BPFs 19 and 20 are analog signals.

  The ADC 21 performs AD conversion (quantization) on the signal supplied from the BPF 19, and supplies a signal obtained by digitizing the signal supplied from the BPF 19 to the digital filter 23. The ADC 22 AD-converts the signal supplied from the BPF 20 and supplies a signal obtained by digitizing the signal supplied from the BPF 20 to the digital filter 23.

  The digital filter 23 filters the digital signals supplied from the ADCs 21 and 22 and supplies them to the power integration processing circuit 24.

  The power integration processing circuit 24 performs a process of integrating the sum of squares of the signal per unit time on the signal supplied from the digital filter 23 and calculates the reception intensity of the modulated wave received by the communication device 11. The power integration processing circuit 24 supplies a signal representing the reception intensity of the modulated wave to the AGC circuit 26.

  The RSSI circuit 25 is supplied with the modulated wave received by the antenna 12 via the BPF 13 and the LNA 14. The RSSI circuit 25 performs a process of extracting an envelope (envelope) on the modulated wave received by the antenna 12, calculates a received intensity (received electric field intensity) of the modulated wave, and a signal representing the received intensity of the modulated wave Is supplied to the AGC circuit 26.

  The AGC circuit 26 is supplied with the received intensity of the modulated wave from the power integration processing circuit 24 or the RSSI circuit 25. Then, the AGC circuit 26 outputs a control signal for controlling the amplification factors of the VGAs 17 and 18 based on the reception intensity of the modulated wave. For example, the AGC circuit 26 outputs a control signal for reducing the amplification factor of the VGAs 17 and 18 if the signal indicating the received intensity of the modulated wave is equal to or greater than a predetermined threshold, while the signal indicating the received intensity of the modulated wave. If it is less than the predetermined threshold, a control signal for increasing the amplification factors of the VGAs 17 and 18 is output.

  The control signal output from the AGC circuit 26 is supplied to the DAC 27, and the DAC 27 converts the control signal into an analog signal (voltage) and supplies it to the VGAs 17 and 18.

  In the communication apparatus 11 configured as described above, the amplification factor of the VGA 17 or 18 is controlled based on the reception intensity of the modulated wave obtained from the baseband signal AD-converted by the ADC 21 or 22. Alternatively, the amplification factor of the VGA 17 or 18 is controlled based on the received intensity of the modulated wave obtained from the modulated wave envelope by the RSSI circuit 25.

  By the way, as a transmission method for transmitting data to be transmitted, as described above, in addition to a transmission method for transmitting data by modulating a carrier wave with a baseband signal that is a signal corresponding to the data to be transmitted, a base is used. There is a transmission method (baseband transmission method) for transmitting the band signal itself.

  In the baseband transmission method, for example, by outputting a magnetic field of one pulse (with or without a magnetic field) from a communication device on the transmission side corresponding to one bit (H level or L level) of data to be transmitted. Data is transmitted.

  In addition, the baseband transmission method can transmit data at a higher speed than the transmission method in which data is transmitted by modulating a carrier wave with a baseband signal. For example, data can be transmitted at a speed of several Gbps or more. Can do.

  Here, as described with reference to FIG. 1, as a method for controlling the amplitude of a received signal in a communication apparatus that performs communication using the baseband transmission method, modulation obtained from the baseband signal AD-converted by the ADC 21 or 22. When a control method for controlling the amplification factor of the VGA 17 or 18 is used based on the wave reception intensity, the ADC 21 or 22 requires a sampling capability at a speed of several Gbps or more. However, it is difficult to perform sampling at a speed of several Gbps or more with a general AD converter, and it is difficult to apply such a control method to a communication device that performs communication using a baseband transmission method. .

  Further, as described with reference to FIG. 1, as a method for controlling the amplitude of a received signal in a communication apparatus that performs communication using the baseband transmission method, the received intensity of the modulated wave obtained from the modulated wave envelope by the RSSI circuit 25 is described. When the control method for controlling the amplification factor of the VGA 17 or 18 is used based on the above, for example, when the data to be transmitted is at the L level, no pulse is output, so it is difficult to obtain the envelope of the received signal. there were. Therefore, it has been difficult to apply such a control method to a communication apparatus that performs communication using the baseband transmission method.

  Here, Patent Document 1 discloses a technique for measuring a received electric field strength with high accuracy in a short time in a receiving circuit that receives a signal modulated by OFDM (Orthogonal Frequency Division Multiplexing). ing.

JP2003-110526A

  As described above, it is difficult to use a conventional control method as a method for controlling the amplitude of a received signal in a communication apparatus that performs communication using the baseband transmission method, and the amplification factor is set so that the received signal has an optimum amplitude. It was difficult to control.

  The present invention has been made in view of such a situation, and makes it possible to control the amplification factor so that the received signal has an optimum amplitude.

A communication apparatus according to an aspect of the present invention is a communication apparatus that performs communication using a baseband transmission method for transmitting data in a baseband, and that receives a reception signal that causes a peak according to a transition in the data level. A first amplification means for amplifying the received signal with a first amplification factor and outputting a first amplification signal; amplifying the first amplification signal with a second amplification factor; Second amplification means for outputting the amplified signal, and the first amplified signal is amplified at a third amplification factor obtained by multiplying the second amplification factor by a predetermined coefficient to obtain a third amplification Based on the comparison result obtained by comparing the third amplification means for outputting a signal, the peak value of the second amplified signal, and a predetermined threshold value, the level of the output data is changed, and the output data is outputted. Output data output means and a pin of the third amplified signal; And click value, the output data output means based on the comparison comparing the threshold and the same threshold used in the comparison result, by transitioning the level of the comparison data, the comparison data output means for outputting the comparison data, The output data output means measures a count value , which is the number of times the level of the comparison data has changed , for each measurement period corresponding to a predetermined period of the output data output period, and a time corresponding to the predetermined period of the measurement period For each gain control period corresponding to, a gain control means for controlling the first gain based on the count value is provided.

A communication method or program according to one aspect of the present invention performs communication using a communication method of a communication apparatus that performs communication using a baseband transmission method that transmits data in baseband, or performs communication using a baseband transmission method that transmits data using baseband. A program that is executed by a computer that controls a communication device, wherein the communication device receives a reception signal that causes a peak in response to a transition of the data level, and receives the reception signal with a first amplification factor. A first amplifying means for amplifying the first amplified signal and outputting a first amplified signal; a second amplifying means for amplifying the first amplified signal at a second gain and outputting a second amplified signal; A third amplification means for amplifying the first amplification signal by a third amplification factor obtained by multiplying the second amplification factor by a predetermined coefficient, and outputting a third amplification signal; Output data output means for outputting the output data by changing the level of the output data based on a comparison result obtained by comparing the peak value of the amplified signal of 2 and a predetermined threshold value; Comparison data output means for changing the level of comparison data and outputting the comparison data based on the comparison result of comparing the peak value with the same threshold value as the threshold value used for comparison by the output data output means. The output data output means measures a count value , which is the number of times the level of the comparison data has transitioned, for each measurement period corresponding to a predetermined period of the output data output period; And a step of controlling the first amplification factor based on the count value for each gain control period corresponding to the time .

In one aspect of the present invention, a communication device receives a reception signal that generates a peak in response to a transition in data level, amplifies the reception signal with a first amplification factor, The first amplification means for outputting, the second amplification means for amplifying the first amplified signal with the second amplification factor, and outputting the second amplified signal, and the first amplification signal for the second amplification factor And a third amplifying means for amplifying at a third amplification factor obtained by multiplying by a predetermined coefficient and outputting a third amplified signal. In addition, the communication device includes: an output data output unit that changes the level of the output data based on a comparison result obtained by comparing the peak value of the second amplified signal and a predetermined threshold; 3. Comparison data output that outputs comparison data by changing the level of comparison data based on the comparison result of comparing the peak value of the amplified signal 3 and the threshold value used by the output data output means for comparison Means. Then, for each measurement period corresponding to a predetermined period of the output data output period , a count value, which is the number of times the comparison data level has transitioned, is measured, and a gain corresponding to the predetermined period of the measurement period For each control period , the first amplification factor is controlled based on the measured count value .

  According to one aspect of the present invention, the amplification factor can be controlled so that the received signal has an optimum amplitude.

You description of the embodiments of the present invention are described below.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 2 shows an embodiment of a communication system to which the present invention is applied (a system refers to a logical collection of a plurality of devices, regardless of whether or not each configuration device is in the same housing). It is a perspective view which shows the structural example of this form.

  In FIG. 2, the communication system is composed of communication devices 41 and 42. The communication devices 41 and 42 are configured in the same manner. However, in the following, a case where data is transmitted from the communication device 41 to the communication device 42, that is, the communication device 41 is set as a transmission side for transmitting data, and communication is performed. The device 42 will be described as a receiving side that receives data.

Communication device 41 includes a transmission-side board 51, the transmission-side board 51, connector 52, and a transmission IC 53, and form the four coil antennas 54 ₁ to 54 _4.

  The connector 52 is connected to a cable for connecting the transmission-side substrate 51 to a power source or other substrate (not shown) provided in the communication device 41, and the connector 52 is connected to the transmission IC 53 via the connector 52. Power and data are supplied.

The transmission IC 53 is driven by power supplied from a power source (not shown) via the connector 52. Further, the transmission IC53, depending on the data to be transmitted to the communication device 42, supplying current to the antenna 54 ₁ to 54 ₄ (flow).

The antenna 54 ₁ to 54 _4, by flowing current supplied from the transmission IC 53, a magnetic field that penetrates the antenna 54 ₁ to 54 ₄ (the white arrow shown in FIG. 2) is generated . This magnetic field changes as the current flowing through the antennas 54 _{1 to} 54 ₄ changes.

Communication device 42 includes a reception-side board 61, the reception-side board 61, connector 62, and a receiving IC 63, and form the four coil antennas 64 ₁ to 64 _4.

  The connector 62 is connected to a cable for connecting the receiving-side board 61 to the power supply or other board (not shown) provided in the communication device 42, and the receiving IC 63 is connected to the receiving IC 63 via the connector 62. Power is supplied.

The receiving IC 63 is driven by power supplied from a power source (not shown) via the connector 62. Receiving IC63 is the induced electromotive force generated in the antenna 64 ₁ to 64 ₄ receives the data transmitted from the transmission-side board 51, the data, via the connector 62, fed to the other substrate (not shown) To do.

In the antennas 64 _{1 to} 64 ₄ , induced electromotive force is generated by electromagnetic induction due to a change in the magnetic field generated by the antennas 54 _{1 to} 54 ₄ of the transmission side substrate 51.

The antennas 64 _{1 to} 64 ₄ are configured in the same manner, and when it is not necessary to distinguish the antennas 64 _{1 to} 64 ₄ , hereinafter, the antennas 64 _{1 to} 64 ₄ are appropriately referred to as the antenna 64. Similarly, the antennas 54 _{1 to} 54 ₄ are referred to as the antenna 54.

  Next, transmission of data from the transmission side substrate 51 to the reception side substrate 61 will be described with reference to FIG.

  The first data from the top of FIG. 3 shows data transmitted by the transmission side board 51, and the second from the top of FIG. 3 flows to the antenna 54 for transmitting this data to the reception side board 61. Current is shown.

  That is, if the data transmitted from the transmission side substrate 51 is H level (for example, 1), the transmission IC 53 causes a current to flow through the antenna 54, and the data transmitted from the transmission side substrate 51 is L level (for example, 0), the current flowing through the antenna 54 is stopped. Therefore, when the data transmitted from the transmission-side substrate 51 changes from the L level to the H level, the current flowing through the antenna 64 increases. On the other hand, when the data transmitted from the H level to the L level, the current flowing through the antenna 64 increases. Decrease.

  Further, when a current flows through the antenna 54, a magnetic field that penetrates the antenna 54 is generated, and this magnetic field changes according to a change in the current flowing through the antenna 54. Then, an induced electromotive force due to electromagnetic induction is generated in the antenna 64 of the reception side substrate 61 due to a change in the magnetic field generated in the antenna 54.

  For example, when the current flowing through the antenna 54 of the transmission side board 51 increases, a positive induced electromotive force is generated at the antenna 64 of the reception side board 61, while when the current flowing through the antenna 54 of the transmission side board 51 decreases, reception occurs. A negative induced electromotive force is generated in the antenna 64 of the side substrate 61. The reception-side board 61 receives a reception signal corresponding to the voltage generated by the induced electromotive force generated in the antenna 64.

  The third from the top in FIG. 3 shows a reception signal (a reception signal amplified by a VGA 77 in FIG. 4 described later) corresponding to the induced electromotive force generated in the antenna 64.

  The reception signal corresponding to the induced electromotive force generated in the antenna 64 has a positive peak according to the transition from the L level to the H level of the data transmitted from the transmission side substrate 51 and is transmitted from the transmission side substrate 51. In accordance with the transition of the data from the H level to the L level, the shape has a negative peak.

  The reception-side board 61 outputs data based on the comparison result obtained by comparing the peak value of the reception signal with the threshold value H or L set in the reception IC 63 of the reception-side board 61.

  In the fourth (bottom) from the top of FIG. 3, data output from the reception-side board 61 is shown.

  That is, when the positive peak value of the received signal is greater than or equal to the threshold value H (> 0), the reception-side board 61 transitions from the L level to the H level, while when the received signal is less than or equal to the threshold value L (<0). Data that transitions from the H level to the L level is output.

  As described above, the reception-side board 61 receives and outputs the data transmitted from the transmission-side board 51.

  Here, the reception intensity of the received signal corresponding to the induced electromotive force generated in the antenna 64, for example, the peak value of the received signal varies depending on the distance between the communication devices 41 and 42, and As the distance increases, the peak value of the received signal decreases. For example, when the peak value P of the received signal shown in FIG. 3 is less than the threshold value H, the data transmitted by the transmission-side substrate 51 has transitioned from the L level to the H level. Nevertheless, the data output from the receiving side board 61 does not change from the L level to the H level. That is, the receiving side board 61 outputs erroneous data.

  Further, for example, the influence of ringing due to mismatch between the antenna 54 of the communication device 41 and the antenna 64 of the communication device 42 is increased, or the reception signal received by the antenna 64 is influenced by the influence of a magnetic field leaked from the adjacent antenna 54. Noise may occur. When the noise peak generated in this way becomes large, for example, when the noise peak value N shown in FIG. 3 is equal to or greater than the threshold value L, the data output from the receiving IC 63 is changed from the H level to the L level. Transition to the level. Also in this case, the receiving side board 61 outputs erroneous data.

  Thus, in order to avoid the reception side substrate 61 from outputting erroneous data, the reception IC 63 of the reception side substrate 61 has a sufficient width (guard band) between the peak value P of the reception signal and the threshold value H. ) And an amplification factor such that a sufficient width (guard band) is provided between the noise peak value N and the threshold value L. Controls the amplification factor of the amplifier.

  Next, FIG. 4 is a block diagram showing a configuration example of one embodiment of the reception IC 63 of FIG.

  In FIG. 4, the receiving IC 63 includes resistors 71 and 72, an amplifier (AMP) 73, an amplification control unit 74, an amplifier (AMP) 75, and a comparator 76. The amplification control unit 74 includes a VGA 77, an amplifier ( AMP) 78, memory 79, comparator 80, AGC circuit 81, and center voltage supply unit (VC) 82.

  In addition, a coiled antenna 64 is connected to the receiving IC 63, and both ends of the antenna 64 are connected to two input terminals of the amplifier 73, respectively. In addition, one end of a resistor 71 is connected to a connection point between one end of the antenna 64 and one of the two input terminals of the amplifier 73, and the other end of the antenna 64 and 2 of the amplifier 73 are connected. One end of a resistor 72 is connected to a connection point with the other input terminal of the two input terminals. The other end of the resistor 72 is connected to the other end of the resistor 71, and a predetermined reference voltage VREF is supplied to this connection point.

  As described above, the circuit composed of the antenna 64, the resistors 71 and 72, and the amplifier 73 generates an induced electromotive force in the antenna 64 in accordance with a change in the magnetic field generated in the antenna 54 of the transmission side substrate 51 in FIG. Then, a potential difference is generated between the two input terminals of the amplifier 73.

  The amplifier 73 amplifies the potential difference generated between the two input terminals, that is, the voltage between the two input terminals with a predetermined amplification factor, and outputs a reception signal corresponding to the induced electromotive force generated at the antenna 64.

  The amplification control unit 74 is supplied with the reception signal output from the amplifier 73. The amplification control unit 74 amplifies the reception signal to an optimum amplitude as described with reference to FIG. V is supplied to the amplifier 75.

  The amplifier 75 amplifies the signal V supplied from the amplification control unit 74 with a predetermined amplification factor A, and supplies the signal VA obtained as a result to the comparator 76.

A signal VA is supplied from the amplifier 75 to the input terminal + of the comparator 76, and a center voltage serving as a reference for comparison with the signal VA is supplied from the center voltage supply unit 82 to the input terminal −. The comparator 76 compares the signal VA supplied from the amplifier 75 with a threshold H (> 0) or a threshold L (<0) with the center voltage supplied from the center voltage supply unit 82 as a reference (0). Based on the comparison result, data D _A is output. For example, the comparator 76, the signal VA supplied from the amplifier 75, if the threshold value H or more, the level of data D _A to transition from L level to H level, if it is not more than the threshold L, the level of the data D _A Is shifted from the H level to the L level. The comparator 76 supplies the data D _A to the AGC circuit 81 of the amplification control unit 74 and also supplies the data D _A to other boards included in the communication device 42 as data (data to be transmitted) received by the reception side board 61. To do.

  The VGA 77 is supplied with the reception signal output from the amplifier 73. The VGA 77 amplifies the reception signal at an amplification factor corresponding to the control signal (voltage) supplied from the AGC circuit 81, and the signal V obtained as a result is amplified. , Supplied to amplifiers 75 and 78.

  The amplifier 78 amplifies the signal V supplied from the VGA 77 with an amplification factor B based on the threshold coefficient stored in the memory 79, and supplies the resulting signal VB to the comparator 80.

  Here, the threshold coefficient for determining the amplification factor B of the amplifier 78 is, for example, based on the evaluation (experiment or simulation) of communication between the communication devices 41 and 42 between the peak value P and the threshold value H in FIG. The value is set such that the guard band is maximized and the guard band between the noise peak value N and the threshold L is maximized. The amplification factor B of the amplifier 78 is a value obtained by multiplying the amplification factor A of the amplifier 75 by a threshold coefficient.

  For example, in the example of FIG. 4, 0.5 is stored as the threshold coefficient in the memory 79, and the amplification factor B of the amplifier 78 is 0.5 times the amplification factor A of the amplifier 75. Specifically, when the amplification factor A of the amplifier 75 is 4, the amplification factor B of the amplifier 78 is two.

  The memory 79 stores a threshold coefficient for determining the amplification factor B of the amplifier 78.

The comparator 80, similarly to the comparator 76 compares the signal VB supplied from the amplifier 78, and a threshold value H or L, based on the comparison result, and outputs the data D _B. For example, the comparator 80, the signal VB supplied from the amplifier 78, if the threshold value H or more, the level of data D _B to transition from L level to H level, if it is not more than the threshold L, the level of data D _B Is shifted from the H level to the L level. The comparator 80 supplies the data D _B to the AGC circuit 81.

The AGC circuit 81, together with the data D _A is supplied from the comparator 76, the data D _B fed from the comparator 80, the AGC circuit 81 based on the data D _A and data D _B, controls the amplification factor of VGA77 To do.

  The center voltage supply unit 82 supplies the comparator 76 and the comparator 80 with a center voltage serving as a reference for comparison.

  Next, the relationship between the amplification factor B of the amplifier 78 and the threshold values H and L and the relationship between the amplification factor A of the amplifier 75 and the threshold values H and L will be described with reference to FIG.

  A signal VB supplied from the amplifier 78 to the comparator 80 is shown on the upper side of FIG. 5, and a signal VA supplied from the amplifier 75 to the comparator 76 is shown on the lower side.

  As described with reference to FIG. 3, the signal V output from the VGA 77 has a positive peak according to the transition from the L level to the H level of the data transmitted from the transmission side substrate 51 of FIG. 2. The signal VB output from the amplifier 78 and the signal VA output from the amplifier 75 have a negative peak in accordance with the transition from the H level to the L level of the data transmitted from the transmission side substrate 51. It has the same shape as the signal V output from the VGA 77.

  As shown in FIG. 5, the amplifier 78 has a positive peak value of the signal VB output from the amplifier 78 that is substantially the same value as the threshold value H, and a negative peak value of the signal VB is substantially the same value as the threshold value L. The amplification factor B is set. Further, since the amplification factor B of the amplifier 78 is set to be 0.5 times the amplification factor A of the amplifier 75, the positive peak value of the signal VA output from the amplifier 75 is almost equal to the threshold value H. The value is doubled, and the negative peak value of the signal VA is almost twice the threshold value L.

  When the reception intensity of the received signal fluctuates, the AGC circuit 81 causes the signal input to the amplifier 78 so that the positive peak value of the signal VB output from the amplifier 78 becomes substantially the same value as the threshold value H. V is controlled, that is, the amplification factor of the VGA 77 that outputs the signal V is controlled. As a result, even if the reception intensity of the reception signal varies, the positive peak value of the signal VA output from the amplifier 75 falls within the amplitude range as shown in FIG. This is avoided. The same applies to the negative peak value of the signal VA output from the amplifier 75.

  Further, it is avoided that the noise peak value of the signal VA output from the amplifier 75 falls within the amplitude range as shown in FIG.

  Next, the control of the amplification factor of the VGA 77 by the AGC circuit 81 of FIG. 4 will be described with reference to FIG.

  FIG. 6 shows a signal VB output from the amplifier 78.

  As described with reference to FIG. 5, the AGC circuit 81 controls the signal V input to the amplifier 78 so that the positive peak value of the signal VB output from the amplifier 78 becomes substantially the same value as the threshold value H. For example, the AGC circuit 81 counts the number of times that the positive peak of the signal VB output from the amplifier 78 becomes equal to or higher than the threshold value H at every predetermined measurement cycle, and if the number is large, the amplification factor of the VGA 77 is increased. If the number is reduced and the number of times is small, the gain of the VGA 77 is controlled so as to increase the gain of the VGA 77.

  That is, as shown in FIG. 6, in the section S1 shown on the left side, the number of times that the positive peak of the signal VB output from the amplifier 78 becomes equal to or greater than the threshold value H is 0. Control is performed to increase the amplification factor of the VGA 77. In the section S3 shown on the right side, the positive peaks of the signal VB output from the amplifier 78 are all equal to or higher than the threshold value H, so that the AGC circuit 81 performs control to reduce the amplification factor of the VGA 77. I do. By such control, the positive peak value of the signal VB output from the amplifier 78 becomes substantially the same value as the threshold value H as in the section S2 shown in the center.

  Next, FIG. 7 is a block diagram showing a configuration example of the AGC circuit 81 of FIG.

  In FIG. 7, an AGC circuit 81 includes a measurement cycle determination unit 91, a gain control cycle determination unit 92, a detection unit 93, a counter 94, a gain table storage unit 95, a gain control value determination unit 96, a gain calculation unit 97, and a DA converter. 98.

The measurement cycle determining section 91, the data D _A is supplied from the comparator 76 in FIG. 4. Measuring cycle determining unit 91, based on the period of the data D _A from the comparator 76, the detection unit 93 determines the measurement period for measuring the supplied data D _B from the comparator 80 (range) (window). For example, the measurement cycle determining unit 91, as shown in FIG. 8 to be described later, the second period time of the data D _A from the comparator 76 is determined as the measurement period. Then, the measurement cycle determination unit 91 sends a trigger signal indicating the end of the measurement cycle (start of the next measurement cycle) determined based on the data D _A from the comparator 76 to the detection unit 93 and the gain control cycle determination unit 92. Supply.

  The gain control cycle determination unit 92 determines a gain control cycle, which is a cycle in which the AGC circuit 81 controls the amplification factor of the VGA 77, based on the trigger signal supplied from the measurement cycle determination unit 91. For example, as shown in FIG. 9 to be described later, the gain control cycle determination unit 92 determines a time corresponding to four measurement cycles determined by the measurement cycle determination unit 91 as a gain control cycle. The gain control cycle determination unit 92 supplies a trigger signal indicating the end of the gain control cycle (start of the next gain control cycle) to the counter 94.

The detection unit 93, the data D _B fed from the comparator 80 in FIG. 4. Detector 93, for each measurement period determined by measuring cycle determining unit 91 measures the level of the supplied data D _B from the comparator 80, toggle the data D _B (i.e., the switching of the level of data D _B) A detection signal indicating whether or not is detected is supplied to the counter 94. That is, the detection unit 93, supply for each measurement period, the detection signal indicating that the toggling of data D _B has been detected, or the detection signal indicating that the toggling of data D _B is not detected, the counter 94 To do.

Counter 94, for each gain control period determined by the gain control cycle determining section 92, the detection signal supplied from the detection unit 93 counts the number of times the toggling of data D _B indicates that it has been detected. Then, the counter 94, the count value indicating the number of times toggle data D _B has been determined, and supplies the gain control value determination unit 96.

A gain table storage unit 95, a count value indicating the number of times the toggling of data D _B has been determined, the gain table that associates control value used to calculate the amplification factor of VGA77 stored.

  In the gain table, the control value “0” is associated with the reference count value, and the negative control value is associated with the count value smaller than the reference count value, which is the reference. A positive control value is associated with a count value larger than the count value. For example, in the gain table, the count value “0” and the control value “+1”, the count values “2” and “3”, the control value “0”, the count value “3”, and the control value “−1” It is associated.

The gain control value determination unit 96, the count value indicating the number of times toggle data D _B has been determined is supplied from the counter 94. The gain control value determination unit 96 refers to the gain table stored in the gain table storage unit 95, determines a control value used for calculating the amplification factor of the VGA 77 based on the count value from the counter 94, and The control value is supplied to the gain calculation unit 97.

  The gain calculation unit 97 stores the current amplification factor of the VGA 77 and a change amount for changing the amplification factor of the VGA 77 corresponding to the control value “1”. Then, the gain calculation unit 97 calculates a new amplification factor of the VGA 77 based on the control value supplied from the gain control value determination unit 96.

  For example, when the control value “0” is supplied from the gain control value determination unit 96, the gain calculation unit 97 sets the same amplification factor as the current amplification factor as the new amplification factor of the VGA 77 (that is, the amplification factor). Do not change). Further, when the control value “+1” is supplied from the gain control value determination unit 96, the gain calculation unit 97 sets the value obtained by adding the change amount to the current amplification factor as a new amplification factor of the VGA 77, When the control value “−1” is supplied from the control value determination unit 96, a value obtained by subtracting the change amount from the current amplification factor is set as a new amplification factor of the VGA 77.

  Further, for example, when the control value “+2” or “+3” is supplied from the gain control value determination unit 96, the gain calculation unit 97 adds a value obtained by doubling or tripleting the change amount to the current amplification factor. The value is the new gain of VGA77.

  The DA converter 98 is supplied with the new amplification factor of the VGA 77 calculated by the gain calculation unit 97. The DA converter 98 converts the amplification factor into an analog control signal (voltage) and supplies it to the VGA 77 in FIG. To do.

  Next, the measurement cycle determined by the measurement cycle determination unit 91 and the detection signal output from the detection unit 93 will be described with reference to FIG.

In FIG. 8, in order from the top to the bottom, the data D _A supplied to the measurement cycle determination unit 91, the measurement cycle determined by the measurement cycle determination unit 91, the data D _B supplied to the detection unit 93, the detection unit 93 detects the operation timing represents a timing for detecting the toggling of data D _B, and the detection signal detection unit 93 outputs are shown.

As described above, the measurement cycle determining unit 91 determines the measurement period based on the period of the data D _A from the comparator 76 in FIG. 4. In the example of FIG. 8, between the time each other that data D _A is shifted from the level L to the level H, as one cycle of the data D _A, time of two cycles of the data D _A, are the measurement period.

In the example of FIG. 8, in the first measurement cycle from the left, the level of data D _B has the H level, data D _B are, at the timing of transition from L level to H level, the detection unit 93 has data D The toggle of _B is detected, and the detection operation timing is set to “1”. The detection operation timing is reset at the end of the measurement cycle. Thus, in this measurement cycle, the detection unit 93 transmits a "1" bit of the detection signal indicating that the toggling of data D _B are detected. Also, as with the measurement period, the 4-th measurement cycle from the left, the level of data D _B has the H level, at this timing, the detection operation timing is set to "1", detector 93 A detection signal “1” is transmitted. The detection unit 93, in the second and third measurement intervals from the left, and transmits the "0" 1-bit detection signal indicating that the toggling of data D _B has not been detected.

  Next, the gain control period determined by the gain control period determining unit 92, the count value output by the counter 94, and the control value determined by the gain control value determining unit 96 will be described with reference to FIG.

  In FIG. 9, the measurement cycle determined by the measurement cycle determination unit 91, the detection signal output by the detection unit 93, the gain control cycle determined by the gain control cycle determination unit 92, and the counter 94 are output in order from top to bottom. Processing according to the count value to be performed and the control value determined by the gain control value determination unit 96 is shown.

  As described above, the gain control cycle determination unit 92 determines the gain control cycle based on the measurement cycle determined by the measurement cycle determination unit 91. In the example of FIG. 9, a time corresponding to four measurement periods is set as a gain control period.

Further, in FIG. 9, in the first gain control cycle from the left, the detection signal of 1 bit indicating that the toggle data D _B has been detected "1" are output only once, the second from the left in gain control cycle, detection signal of 1 bit indicating that the toggle data D _B has been detected, not output. Further, in the fourth gain control cycle from the left, the detection signal of 1 bit indicating that the toggle data D _B has been detected "1" are output only once, in the fourth gain control cycle from the left , the detection signal of one bit indicating that the toggle data D _B has been detected "1" is output only three times.

  Accordingly, the counter 94 outputs a count value “1” in the first gain control cycle from the left, and outputs a count value “0” in the second gain control cycle from the left, and the third gain from the left. In the control period, the count value “1” is output, and in the fourth gain control period from the left, the count value “3” is output.

  Then, the gain control value determination unit 96 refers to the gain table stored in the gain table storage unit 95 based on the count value output by the counter 94, and in the first gain control cycle from the left, the control value “ 1 "is output, and the amplification factor of the VGA 77 does not change.

  In addition, the gain control value determination unit 96 outputs a control value “0” in the second gain control cycle from the left, thereby increasing the amplification factor of the VGA 77 and in the third gain control cycle from the left. A control value “1” is output, whereby the gain of the VGA 77 does not change, and a control value “3” is output in the fourth gain control cycle from the left, thereby reducing the gain of the VGA 77. .

  Next, FIG. 10 is a flowchart for explaining processing in which the AGC circuit 81 of FIG. 7 controls the VGA 77 of FIG.

For example, a receiving IC63 is ready for communication processing is started, in step S11, the detection unit 93 starts measuring the level of the supplied data D _B from the comparator 80.

After the process of step S11, the process proceeds to step S12, and the detection unit 93 determines whether or not the measurement cycle determined by the measurement cycle determination unit 91 has elapsed, that is, the measurement cycle determination unit 91 ends the measurement cycle. It determines whether the trigger signal is supplied indicating, to the measurement period determined by measuring cycle determining unit 91 is determined to have elapsed, a measurement of the level of the supplied data D _B from the comparator 80.

In step S12, the detection unit 93, when the measurement period determined by measuring cycle determining unit 91 is determined to have elapsed, the process proceeds to step S13, the detection signal indicating whether a toggle data D _B has been detected Is supplied to the counter 94. That is, the detection unit 93, within the measurement period, if it is detected toggling of data D _B, and supplies a detection signal indicating that the toggling of data D _B has been detected to the counter 94, whereas, the data D _B if the toggle is detected, and supplies a detection signal indicating that the toggling of data D _B has not been detected in the counter 94.

After the processing in step S13, the process proceeds to step S14, the counter 94, the detection unit 93 at step S14, the toggle data D _B counts the number of times the detection signal is supplied to indicate that it has been detected. That is, in step S15 to be described later until it is determined that the gain control cycle is finished, the processing of steps S12 to S15 is repeated, the detection unit 93 at step S13, the detection indicating that the toggling of data D _B has been detected If the signal is supplied a plurality of times, the counter 94 counts the number of times.

  After the process of step S14, the process proceeds to step S15, and the counter 94 determines whether or not the gain control period determined by the gain control period determining unit 92 has elapsed, that is, the gain control period determining unit 92 determines the gain control period. It is determined whether or not a trigger signal indicating termination has been supplied.

  In step S15, when the counter 94 determines that the gain control cycle determined by the gain control cycle determination unit 92 has elapsed, the process proceeds to step S16, while the gain control determined by the gain control cycle determination unit 92 is performed. If it is determined that the cycle has not ended, the process returns to step S12, and the same process is repeated thereafter.

  In step S <b> 16, the counter 94 supplies a count value indicating the number of times counted in step S <b> 14 to the gain control value determination unit 96.

  After the process of step S16, the process proceeds to step S17, and the gain control value determination unit 96 refers to the gain table stored in the gain table storage unit 95, and based on the count value supplied from the counter 94 in step S16. Thus, the control value used for calculating the amplification factor of the VGA 77 is determined. The gain control value determination unit 96 supplies the control value to the gain calculation unit 97, and the process proceeds to step S18.

  In step S18, the gain calculation unit 97 calculates a new amplification factor of the VGA 77 based on the control value supplied from the gain control value determination unit 96 in step S17. The new gain calculated by the gain calculation unit 97 is supplied to the VGA 77 in FIG. 4 via the DA converter 98, and the VGA 77 amplifies the received signal based on the new gain calculated by the gain calculation unit 97. And output. After the process of step S18, the process returns to step S12, and the same process is repeated thereafter.

As described above, AGC circuit 81, for each gain control period determined by the gain control cycle determining section 92, based on the count value, which is the number of times the toggling of data D _B has been detected, controlling the amplification factor of VGA77 Therefore, the amplification factor can be controlled so that the signal V output from the VGA 77 has an optimum amplitude. Thereby, the communication apparatus 42 can avoid outputting erroneous data as described with reference to FIG. 3, and the quality of communication with the communication apparatus 41 can be improved. That is, the communication error rate and the I component pattern of the received signal can be improved.

  Further, for example, when the amplification factor of the VGA 77 is fixed, the communication distance between the communication devices 41 and 42 becomes narrow. However, the AGC circuit 81 controls the amplification factor of the VGA 77 to optimize the VGA 77 amplification factor. Since a reception signal with a large amplitude can be obtained, the communication distance between the communication devices 41 and 42 can be increased.

  In addition, when the AGC circuit 81 controls the amplification factor of the VGA 77, the change range of the amplification factor of the VGA 77 is widened. Thereby, for example, the dimensional error at the time of attaching the receiving-side substrate 61 to the communication device 42 can be made wider than before, and the manufacturing yield of the communication device 42 can be improved.

  Here, for example, when the 8B10B encoding method is used as an encoding method for encoding data to be transmitted, the gain of the VGA 77 can be controlled using the envelope (envelope) of the received signal. In the 8B10B encoding method, a pulse is generated even when data is not transmitted, so that power consumption increases. On the other hand, when the AGC circuit 81 controls the amplification factor of the VGA 77, no pulse is generated when data is not transmitted, so that an increase in power consumption can be suppressed.

  In addition, when using the 8B10B encoding method as an encoding method for encoding data to be transmitted, in order not to generate a pulse even when data is not transmitted, before starting data transmission However, there is a problem that it is necessary to generate a preamble pulse for the envelope transition period, and that data cannot be transmitted without processing the data to be transmitted. These problems do not occur when controlling the amplification factor.

The measurement period and the gain control period may be not determined on the basis of the data D _A to the comparator 76 outputs, for example, it may be a fixed period set in advance.

Further, a count value indicating the number of times the toggling of data D _B has been measured, without referring to the gain table associating the control value used to calculate the amplification factor of VGA77, simply based on the count value, The amplification factor of the VGA 77 may be increased or decreased by a certain amount of change.

  In addition, when there are a plurality of channels for transmitting data, for example, when there are four channels for transmitting data as in the reception-side board 61 of FIG. A receiving circuit including the amplification control unit 74, the amplifier 75, the comparator 76, and the like is configured.

In this way, by configuring a receiving circuit for each channel for transmitting data, for example, the transmission side substrate 51 of the communication device 41 and the reception side substrate 61 of the communication device 42 do not face each other in parallel, When facing each other in an inclined manner, the distances between the antennas 54 _{1 to} 54 ₄ and the antennas 64 _{1 to} 64 ₄ are different from each other. Even in such a case, reception is performed so that the optimum amplitude is obtained for each channel. The signal is amplified, and good communication can be performed on all channels.

  Also, for example, when all the received signals of each channel are amplified with the same amplification factor, the transmission side substrate 51 of the communication device 41 and the reception side substrate 61 of the communication device 42 do not face each other in parallel. If they face each other in an inclined manner, as shown in FIG. 11, a skew occurs between a received signal of a channel with a short communication distance and a received signal of a channel with a long communication distance. On the other hand, by configuring a receiving circuit for each channel for transmitting data, the received signal is amplified so that all channels have the same amplitude. It is possible to avoid the occurrence of skew between the received signal and the long channel.

  Next, part or all of the processing performed by the AGC circuit 81 described above can be performed by hardware or can be performed by software. When a series of processing is performed by software, a program constituting the software is installed in a microcomputer functioning as the AGC circuit 81 (a computer built in the AGC circuit 81 and controlling the AGC circuit 81) or the like.

  Therefore, FIG. 12 shows a configuration example of an embodiment of a computer (microcomputer) in which a program for executing the series of processes described above is installed.

  The program can be recorded (installed) in advance in an EEPROM (Electrically Erasable Programmable Read-only Memory) 105 or ROM 103 as a recording medium built in the computer.

  Alternatively, the program is temporarily or permanently stored on a removable recording medium such as a flexible disk, CD-ROM (Compact Disc Read Only Memory), MO (Magneto Optical) disk, DVD (Digital Versatile Disc), magnetic disk, or semiconductor memory. Can be stored (recorded) automatically.

  The program is installed on the computer from the removable recording medium as described above, and is also wired to the computer via a wired or wireless network. The computer inputs the program transferred in this way. It can be received by the output interface 110 and installed in the built-in EEPROM 105.

  In a computer, a CPU (Central Processing Unit) (or DSP (Digital Signal Processor)) 102, a ROM (Read Only Memory) 103, a RAM (Random Access Memory) 104, an EEPROM 105, and an input / output interface 110 are connected via a bus 101. Connected.

  The CPU 102 loads a program stored in a ROM (Read Only Memory) 103 or an EEPROM 105 to a RAM (Random Access Memory) 104 and executes it. Thus, the CPU 102 performs processing according to the above-described flowchart or processing performed by the configuration of the above-described block diagram. Note that data exchange with the outside is performed via the input / output interface 110.

  The program executed by the computer may be a program that is processed in time series in the order described in this specification, or in parallel or at a necessary timing such as when a call is made. It may be a program for processing.

  Note that the processes described with reference to the flowcharts described above do not necessarily have to be processed in chronological order in the order described in the flowcharts, but are performed in parallel or individually (for example, parallel processes or objects Processing). The program may be processed by one CPU, or may be distributedly processed by a plurality of CPUs.

  The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows the structure of an example of the conventional communication apparatus. It is a perspective view which shows the structural example of one Embodiment of the communication system to which this invention is applied. It is a figure explaining the transmission of the data from the transmission side board | substrate 51 to the reception side board | substrate 61. FIG. 4 is a block diagram illustrating a configuration example of an embodiment of a reception IC 63. FIG. It is a figure explaining the relationship between an amplification factor and a threshold value. It is a figure explaining control of the amplification factor of VGA77 by AGC circuit 81. 3 is a block diagram illustrating a configuration example of an AGC circuit 81. FIG. It is a figure explaining the measurement period which the measurement period determination part 91 determines, and the detection signal which the detection part 93 outputs. It is a figure explaining the gain control period determined by the gain control period determination part 92, the count value which the counter 94 outputs, and the control value which the gain control value determination part 96 determines. 5 is a flowchart for explaining processing in which an AGC circuit 81 controls a VGA 77. It is a figure explaining the skew of a received signal. It is a block diagram which shows the structural example of one Embodiment of the computer to which this invention is applied.

Explanation of symbols

41 communication device, 42 communication device, 51 transmit side substrate, 52 a connector, 53 a transmission IC, 54 ₁ to 54 ₄ antennas 61 receiving-side substrate, 62 a connector, 63 a receiving IC, 64 ₁ to 64 ₄ antennas, 71 and 72 resistors, 73 amplifiers, 74 amplification control units, 75 amplifiers, 76 comparators, 77 VGA, 78 amplifiers, 79 memories, 80 comparators, 81 AGC circuit, 82 center voltage supply unit, 91 measurement cycle determination unit, 92 gain control cycle determination Section, 93 detection section, 94 counter, 95 gain table storage section, 96 gain control value determination section, 97 gain calculation section, 98 DA converter

Claims (5)

In a communication device that performs communication using a baseband transmission method for transmitting data in baseband,
Receiving means for receiving a received signal in which a peak occurs according to a transition of the data level;
A first amplifying means for amplifying the received signal at a first gain and outputting a first amplified signal;
Second amplification means for amplifying the first amplified signal at a second amplification factor and outputting a second amplified signal;
A third amplifying means for amplifying the first amplified signal by a third amplification factor obtained by multiplying the second amplification factor by a predetermined coefficient, and outputting a third amplified signal;
An output data output means for outputting the output data by changing the level of the output data based on a comparison result obtained by comparing the peak value of the second amplified signal with a predetermined threshold;
Based on the comparison result obtained by comparing the peak value of the third amplified signal with the same threshold value used by the output data output means for comparison, the level of the comparison data is changed, and the comparison data is output. Comparison data output means,
The output data output means measures a count value , which is the number of times the level of the comparison data has changed , for each measurement period corresponding to a predetermined period of the output data output period, and a time corresponding to the predetermined period of the measurement period A gain control means for controlling the first gain based on the count value for each gain control period corresponding to . The predetermined coefficient for obtaining the third amplification factor has a maximum width between a peak value of the received signal and a first threshold, and a noise peak value of the received signal, and the first coefficient The communication apparatus according to claim 1, wherein the width of the second threshold value smaller than the threshold value is set to a maximum value . The amplification factor control means includes
Storage means for storing a table in which the predetermined count value and the change amount of the first amplification factor are associated with each other;
A change amount determining means for determining a change amount of the first amplification factor with reference to a table stored in the storage means;
The communication apparatus according to claim 1, further comprising: a calculation unit that newly calculates the first amplification factor based on the change amount determined by the determination unit. In a communication method of a communication device that performs communication by a baseband transmission method for transmitting data in baseband,
The communication device
Receiving means for receiving a received signal in which a peak occurs according to a transition of the data level;
A first amplifying means for amplifying the received signal at a first gain and outputting a first amplified signal;
Second amplification means for amplifying the first amplified signal at a second amplification factor and outputting a second amplified signal;
A third amplifying means for amplifying the first amplified signal by a third amplification factor obtained by multiplying the second amplification factor by a predetermined coefficient, and outputting a third amplified signal;
An output data output means for outputting the output data by changing the level of the output data based on a comparison result obtained by comparing the peak value of the second amplified signal with a predetermined threshold;
Based on the comparison result obtained by comparing the peak value of the third amplified signal with the same threshold value used by the output data output means for comparison, the level of the comparison data is changed, and the comparison data is output. Comparison data output means for
The output data output means measures a count value , which is the number of times the level of the comparison data has changed , for each measurement period corresponding to a predetermined period of the output data output period, and a time corresponding to the predetermined period of the measurement period A control method including the step of controlling the first gain based on the count value for each gain control period corresponding to . In a program to be executed by a computer that controls a communication device that performs communication using a baseband transmission method for transmitting data in a baseband,
The communication device
Receiving means for receiving a received signal in which a peak occurs according to a transition of the data level;
A first amplifying means for amplifying the received signal at a first gain and outputting a first amplified signal;
Second amplification means for amplifying the first amplified signal at a second amplification factor and outputting a second amplified signal;
A third amplifying means for amplifying the first amplified signal by a third amplification factor obtained by multiplying the second amplification factor by a predetermined coefficient, and outputting a third amplified signal;
An output data output means for outputting the output data by changing the level of the output data based on a comparison result obtained by comparing the peak value of the second amplified signal with a predetermined threshold;
Based on the comparison result obtained by comparing the peak value of the third amplified signal with the same threshold value used by the output data output means for comparison, the level of the comparison data is changed, and the comparison data is output. Comparison data output means for
The output data output means measures a count value , which is the number of times the level of the comparison data has changed , for each measurement period corresponding to a predetermined period of the output data output period, and a time corresponding to the predetermined period of the measurement period A program for causing a computer to execute a process including a step of controlling the first gain based on the count value for each gain control period corresponding to .

Images