JP2008167077A - Detection circuit of cdma modulated wave - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detection circuit of a CDMA modulated wave for obtaining detection voltage made to be a power value corresponding to a continuous signal wave even in the case of a burst signal wave. <P>SOLUTION: A control part performs correction of a detection voltage value outputted from a detection circuit 4 so as to make detection voltage values of outputted from both detection circuits to be the same value, calculates a differential voltage value between a detection voltage value outputted from a detection circuit 3 and a correction value of a detection voltage value outputted from the detection circuit 4, discriminates between a continuous signal wave and a burst signal wave by determining the differential voltage value, calculates an input level value of a modulated wave by the detection voltage value outputted from the detection circuit 3, calculates control voltage by the input level value, the detection voltage value and a discrimination result, outputs the control voltage, performs correction by signal processing by software or outputs a hardware command of the level adjustment value to a modulated wave distributor and the both detection circuits. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to level control of a burst signal having a high peak component, and more particularly, to a modulation wave detection circuit in which a continuous signal wave and a burst signal wave exist.

  In a control system that automatically controls the transmission output level of a transmission amplifier of a BTS (Base Transceiver Station Equipment), a transmission signal (carrier) transmitted from a controlled system is a continuous signal wave and a burst signal wave. In the case of a modulated wave in which a continuous signal wave is measured as an average power value, and a value obtained by measuring a burst signal wave power value as an average power value is the same peak power value. However, the latter average power value is measured lower. The difference depends on the ON / OFF time ratio of the burst signal wave.

  There was an integrated circuit (AD8362 detector; integrated circuit for detection manufactured by ANALOG DEVICES) as a detection element used in a detection circuit that detects a modulated signal wave and can automatically control power based on the detection voltage. . (For example, see Non-Patent Document 1)

  In this case, both the burst signal wave and the continuous signal wave can be detected. However, since a lower detection voltage is output in the detection of the burst signal wave, the true value (rms value) of the level of the burst signal wave is obtained. It was difficult to grasp.

  In the case of a transmission modulation wave of a CDMA2000 system using a CDMA (Code Division Multiple Access) system, the peak component level of the modulation wave itself may be higher, that is, the modulation wave is on the time axis. When the amplitude of the waveform appears large or small, a particularly large peak may appear, and there is a further peak value in the waveform when the burst signal is on. In the case of a burst signal wave in which the peak value of such a waveform changes greatly, the measurement difference becomes significant.

  Therefore, in the automatic level (gain) control of the output level of the signal waveform that generates a waveform having a large peak factor and a small waveform on the burst signal wave as described above, the input signal waveform is detected and the control voltage is detected. However, the level value (measured value) detected in the conventionally used detection circuit does not show a value corresponding to the level value of the actual peak power, and is deviated between the two.

  For this reason, when automatic gain control of the controlled system is performed by changing the bias of the amplifying element in accordance with the power, automatic gain control in which both the burst signal wave and the continuous signal wave are correlated cannot be performed. If automatic gain control is performed with reference to the level of the continuous signal wave, the amplification capability of the amplifier is insufficient when the burst signal wave is generated, and distortion is generated in the amplified transmission wave. On the other hand, if automatic gain control is performed on the basis of a burst signal wave, the efficiency of the amplifier is deteriorated when a continuous signal wave is obtained.

Conventionally, on the premise that it is detected whether a signal is a continuous wave or a burst wave, an apparatus using this for temperature control has been proposed. (For example, see Patent Document 1)
Japanese Patent Laying-Open No. 2004-40280 (FIG. 1) Analog Devices catalog (AD8362, AD8313)

  In the detection circuit using the AD8362 alone as the detection element of the prior art, in the detection voltage set when detecting a continuous signal wave of an arbitrary level and the detection circuit set at the level of the continuous signal wave, the burst EV− There is a difference between the detection voltage of the DO modulation wave and the detection voltage of both. In this case, there is a problem that the level of the detection voltage of the continuous signal wave cannot be distinguished, and the operation efficiency of the controlled system (for example, an amplifier) is thereby deteriorated.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and even if the carrier type information from the system side such as the carrier generation unit of the BTS cannot be obtained as control information, the signal input to the controlled system such as an amplifier Based on this, it can be determined whether the input carrier is a continuous signal wave or a burst signal wave, and even if it is a burst signal wave with a large peak level fluctuation when the burst is on, An object of the present invention is to provide a detection circuit for a CDMA modulation wave in which a detection voltage converted into a power value is obtained as a measurement value.

In order to achieve this object, the CDMA modulated wave detection circuit of the present invention receives a modulated wave having a continuous signal wave or burst signal wave as a carrier, detects the modulated wave, and outputs it as a control voltage. CDMA modulation wave detection circuit,
The CDMA modulation wave detection circuit includes: a modulation wave distributor that distributes and outputs the input modulated wave in two; a first detection circuit that receives one of the distribution outputs and performs detection; and The other of the distributed outputs is input, the second detection circuit that performs detection having characteristics different from those of the first detection circuit, and the detection voltage value output from the first and second detection circuits are input, and the detection is performed. A control unit that performs signal processing of a voltage value and outputs the control voltage, and
In the control unit, the detection voltage value output from the second detection circuit is corrected so that the detection voltage value output from the first and second detection circuits is the same value,
By calculating the voltage value of the difference between the detection voltage value output from the first detection circuit and the correction value of the detection voltage value output from the second detection circuit, and determining the voltage value of the difference The continuous signal wave and the burst signal wave are discriminated, and the control voltage corresponding to the carrier level is output.

Further, the control unit calculates an input level value of the modulated wave based on a detection voltage value output from the first detection circuit,
The control voltage is calculated based on the input level value, the detected voltage value, and the identification result, and the control voltage is output.
The correction is performed by the signal processing by software, or a hardware instruction of a level adjustment value is output to the modulated wave distributor and the first and second detection circuits.

  According to the present invention, even if carrier information from the system side such as BTS cannot be obtained, whether the signal is a continuous signal wave based on the currently input (transmission) signal in operation, It is possible to determine whether the signal is a burst signal wave.

  Furthermore, it becomes possible to calculate the set power of the input burst signal wave as a true value, and in both the continuous signal wave and the burst signal wave, the controlled system such as a transmission amplifier according to the true value level of the carrier. Automatic (gain) control can be performed accurately and efficiently, and both continuous signal waves and burst signal waves can be controlled to a predetermined power.

  A conceptual diagram in which the technology of the present invention is applied to a system is shown in FIG. This is a block diagram applied to the control of the controlled system 20. The system output signal is coupled by a coupler, and this is input to the CDMA modulation wave detection circuit 10 of the present invention, detected and output. Controls the (transmission amplification) signal level (amplification gain) of the controlled system 20 (for example, transmission amplifier).

  As long as the controlled system wants to control the power of the signal, it may be a transmission amplifier, a reception amplifier, or other equipment.

  FIG. 4 shows a block diagram of the detection circuit 3 using the AD8362. This is an example of a level detection circuit using the AD8362 alone. In this circuit, CDMA2000, that is, an initial standard of 1X (a system without the concept of a slot; a continuous signal wave) or a new standard of CDMA2000 incorporating a slot concept, EV-DO (Evolution Date Only); When a burst signal wave) is input, the input level versus the output voltage (detection voltage) of each modulated wave operates as a linear characteristic.

  FIG. 5 shows a characteristic diagram of the detection circuit 3 using the AD8362. This is an example of a characteristic diagram of a level detection circuit using AD8362 alone as a detection element. In such a linear characteristic, a burst voltage of EV− in a detection circuit set at a detection voltage a (V) when detecting a continuous signal wave of an arbitrary level α (dBm) and a level α of the continuous signal wave is obtained. In the case of the DO modulation wave, the detection voltage is b (V), and a difference of a (V) −b (V) = c (V) occurs between the two. This makes it impossible to distinguish from the level β (dBm) at which the detection voltage of the continuous signal wave is b (V).

  FIG. 6 shows a functional block diagram of the AD8362 element. This is a functional block of an internal circuit of the detection element AD8362, although the description is omitted.

  Next, FIG. 7 shows a block diagram of the detection circuit 4 using the AD8313. This is an example of a level detection circuit using AD8313 (an integrated circuit for detection manufactured by ANALOG DEVICES) alone. When this integrated circuit for detection (AD8313 detector) is used, the detection operation of the burst signal wave cannot be basically performed by itself.

  FIG. 8 shows a characteristic diagram of the detection circuit 4 using the AD8313. In the detection circuit using AD8313, when EV-DO (burst signal wave) is input, as shown in the characteristic diagram, the detection voltage as the linear characteristic is not output unless the level reaches a considerably high level. It cannot be used alone as a level detection circuit for burst signal waves. FIG. 9 shows a functional block diagram of the AD8313 element. This is a functional block of an internal circuit of the detection element AD8313, although the description is omitted.

  FIG. 1 shows an embodiment of the present invention. Detection of a CDMA modulated wave in which a detection circuit is duplicated by a detection circuit 3 (integrated circuit AD8362 is applied as an example) and a detection circuit 4 (integrated circuit AD8313 is applied as an example). It is a block diagram of a circuit and will be described next.

  A modulated wave (carrier) having a waveform of a continuous signal wave or a burst signal wave is input to the modulated wave input terminal 1. The modulated wave as the system output is detected by a circuit described later, and a control voltage as the final output is output.

  The modulated wave distributor 2 divides the input modulated wave into two for distribution output. Each distribution output is supplied to the detection circuits 3 and 4. The distribution loss is 3 dB lower than the level input to the modulated wave input terminal 1. This value is taken into account when calculating the detection voltage and the control voltage at the signal processing stage of the control unit.

  The detection circuit 3 (detection element AD8362 system) is a main and first detection circuit that performs detection in parallel, and one of the distribution outputs of the modulation wave distributor 2 is input.

  The detection circuit 4 (detection element AD8313 system) is a complementary second detection circuit that performs detection in parallel with the detection circuit 3, and the other of the distribution outputs of the modulation wave distributor 2 is input.

  The detection circuit 3 and the detection circuit 4 send the detected detection voltage to the control unit 5.

  The control unit 5 receives each detection voltage value output from the detection circuit 3 (AD8362 system) and the detection circuit 4 (AD8313 system) having a detection characteristic different from the detection circuit 3 as an input, as described below. Signal processing of each detected voltage value is performed and the control voltage is output.

  The operation of the control unit 5 is such that the detection voltage value output from the detection circuit 3 and the detection circuit of the detection circuit 4 is equal to the detection voltage value output from the detection circuit 4 (AD8313 system), That is, this correction operation is for setting the detection voltage of the continuous signal wave, which is the basis of power measurement, to be the same value between the two detection circuits.

  When a continuous signal wave is detected by such a correction operation, the detection voltage values of the detection circuit 3 and the detection circuit 4 coincide with each other. However, when the burst signal wave is detected, there is still a discrepancy between the corrected detection voltage values of the two detection circuits even in the value after the correction operation. By detecting this discrepancy, it is determined that the input modulated wave (carrier) is a burst signal wave.

  On the other hand, when a burst signal wave is input, the detection voltage of the burst signal wave of the detection circuit 3 on the uncorrected side is the same input level as that of the continuous signal wave, but between the detection voltage of the continuous signal wave c ( There is a difference in V). Therefore, conversely, when γ (dBm), which is the difference in input level corresponding to c (V), is added to the input level of the burst signal wave, the set level of the carrier that is the modulated wave of the burst signal wave If used, it corresponds to a continuous signal wave showing a true value. (See Figure 5)

  Thereafter, the following signal processing is performed in order.

  The voltage value of the difference between the detection voltage value output from the detection circuit 3 and the correction value of the detection voltage value output from the detection circuit 4 is calculated.

  Next, discrimination between the continuous signal wave and the burst signal wave is performed by determining the voltage value of the obtained difference.

  Next, the input level value of the modulated wave is calculated from the detection voltage value output from the detection circuit 3.

  Next, a control voltage is calculated from the input level value, the detected voltage value, and the identification result, and this control voltage is output.

  The signal processing to be corrected may be performed by the signal processing by software built in the control unit 5, or the level adjustment value for the modulation wave distributor and the detection circuits 3 and 4 instead of software. It is good also as a hardware structure performed by the instruction | command (circuit shown by the broken line of FIG. 1) output from the control part 5. FIG. Alternatively, when correction is performed by hardware, the degree of coupling of the modulated wave distributor 2 (eg, coupler element) is changed by a command (a circuit indicated by a broken line in FIG. 1) output from the control unit 5.

  As described above, as a means for performing correction by hardware, a circuit system that changes the detection characteristics of the detection circuit 3 or the detection circuit 4 according to a command from the control unit 5 may be used.

  The control voltage output terminal 6 is connected to the control input of the controlled system and is a terminal that outputs the control voltage.

  FIG. 2 shows a relation table between the input level of the modulated wave (carrier) and the detected voltage value of the present invention, and an embodiment will be described.

  The input level (m) input to the detection circuit 3 and the detection circuit 4 is −40 (dBm) to 0 (dBm). The detection voltage value (n) of the CDMA2000 modulated wave (continuous signal wave) by the detection circuit 3 (AD8362 system) is 1.0 (V) to 3.0 (V) corresponding to the input level value. (See Figure 5)

  Similarly, the detection voltage value (p) of the CDMA2000 modulated wave (continuous signal wave) by the detection circuit 4 (AD8313 system) is 2.0 (V) to 4.0 (V) corresponding to the input level value. (See Figure 7)

  With respect to the detection voltage value of the detection circuit 4 (AD8313 system), an operation for correcting a difference in the detection voltage value corresponding to each input level value is performed by signal processing software included in the control unit 5.

  In this example, correction is performed by adding “−1.0 (V)” to each of detection voltage values 2.0 (V) to 4.0 (V) corresponding to each input level value. The correction value (q) of 1.0 (V) to 3.0 (V) is obtained, and the detection voltage value (n) 1.0 (V) to 3.0 (V) by the detection circuit 3 (AD8362 system) is obtained. To match.

  Since the present invention is a technique for recognizing a signal format from an input signal, first, with respect to an unknown input level X (dBm), a detection voltage value by the detection circuit 3 (AD8362 system) is 2.0 (V ) Detection voltage value (s) is obtained.

  At this time, if the detection voltage value (t) of the detection circuit 4 (AD8313 system) is 3.0 (V), the corrected voltage value (t ′) becomes 2.0 (V) and is input. Since the signal wave is s = t ′ (the detection results of the two detection circuits match), it can be determined that the signal wave is on the continuous signal wave side. That is, the true value of X = −20 (dBm) is obtained for the input level in the column where the two voltage values (s, t ′) are both 2.0 (V).

  On the other hand, if the detection voltage value (u) of the detection circuit 4 (AD8313 system) is 1.5 (V), the corrected voltage value (u ′) is 0.5 (V) and is input. The signal wave is out of the range of “2.0 (V) or less” as a continuous signal wave, that is, an undetectable region, and the detection results of the two detection circuits are inconsistent. It can be determined that there is.

  However, as shown by the detection voltage value (n) of the continuous signal wave and the detection voltage value (w) of the burst signal wave by the detection circuit 3 (AD8362 system), the detection voltage value of the burst signal wave is detected by the detection of the continuous signal wave. It is detected 0.5 (V) lower than the voltage value. The difference of the detection voltage value 0.5 (V) corresponds to the level difference of the input level 10 (dBm), as can be seen from the column of the input level (m).

  Therefore, if the detection voltage value (u, u ′) of the detection circuit 4 (AD8313 system) is 1.5 (V) (u) “corrected voltage 0.5 (V) (u ′)”, the detection is performed. The value “−” of the input level (m) in the column of the detected voltage value “u = 1.5 (V), u ′ = 0.5 (V)” indicated by the upper column of the voltage value of 2.0 (V). 10 (dBm) "is determined to indicate the set level (true value) of the input EV-DO burst signal wave.

  In the embodiment of the present invention, the correction value of the detection voltage value is obtained based on the detection voltage value of the detection circuit 4, but the detection circuits 3 and 4 are obtained based on the detection voltage values of both detection circuits. It is good also as a method of calculating | requiring as a correction value of the detection voltage value of either or both.

  In this embodiment, when the detection voltage value of the detection circuit 3 is V1, and the detection voltage value of the detection circuit 4 is V2, the obtained function Vc = f (V1, V1-V2) is tabulated, and V1 + Vc is corrected. Obtained as the true value of.

  Alternatively, the obtained function Vc = f (V2, V1−V2) is tabulated, and V2 + Vc is obtained as a true value after correction.

  Note that the number of detection circuits and the detection voltage obtained may be two or more, and a method of performing signal processing from the plurality of detection voltage values and further obtaining a control voltage may be used.

  As an example, the present invention is applied to a wireless communication system used for mobile communication and can be used for a communication business or the like.

FIG. 3 is a block diagram of a CDMA modulation wave detection circuit according to the present invention. It is a relational table of the input level and detection voltage value of the detection circuit of the CDMA modulation wave of the present invention. It is a block diagram in which the detection circuit was applied to the controlled system. It is a block diagram of a detection circuit using AD8362. It is a characteristic view of a detection circuit using AD8362. It is a functional block diagram of AD8362 element. It is a block diagram of a detection circuit using AD8313. It is a characteristic view of a detection circuit using AD8313. It is a functional block diagram of AD8313 element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Modulation wave input terminal 2 Modulation wave divider 3 Detection circuit (AD8362 system)
4 Detection circuit (AD8313 system)
DESCRIPTION OF SYMBOLS 5 Control part 6 Control voltage output terminal 10 CDMA modulation wave detection circuit 20 Controlled system 30, 40 Detection element

Claims (1)

A detection circuit for a CDMA modulation wave that receives a modulated wave having a continuous signal wave or a burst signal wave as an input, detects the modulated wave, and outputs it as a control voltage,
The CDMA modulation wave detection circuit includes: a modulation wave distributor that distributes and outputs the input modulated wave in two; a first detection circuit that receives one of the distribution outputs and performs detection; and The other of the distributed outputs is input, the second detection circuit that performs detection having characteristics different from those of the first detection circuit, and the detection voltage value output from the first and second detection circuits are input, and the detection is performed. A control unit that performs signal processing of a voltage value and outputs the control voltage, and
In the control unit, the detection voltage value output from the second detection circuit is corrected so that the detection voltage value output from the first and second detection circuits is the same value,
By calculating the voltage value of the difference between the detection voltage value output from the first detection circuit and the correction value of the detection voltage value output from the second detection circuit, and determining the voltage value of the difference A detection circuit for a CDMA modulation wave in which the continuous signal wave and the burst signal wave are discriminated and the control voltage corresponding to a carrier level is output.

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