JP3722777B2 - High frequency power detection circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency power detection circuit, and more particularly to a high-frequency power detection circuit that enables highly accurate power detection of multicarrier high-frequency signals.
[0002]
[Prior art]
For example, a high frequency power detector is used for output power display and output power control of the final stage power amplifier in the wireless transmission device. Just as the output power control found in W-CDMA is essential, its importance is increasing. However, the elements of the high-frequency power detectors such as diodes and LOG amplifiers used therein generate detection errors because their characteristics change with respect to temperature, input level, and frequency. Therefore, conventionally, a temperature sensor is built in, and based on the output, a reverse characteristic generation circuit compensates the temperature characteristic of the high frequency power detector, and a coupler having a characteristic opposite to the frequency characteristic of the high frequency power detector is provided. By connecting, frequency characteristics are compensated.
[0003]
The conventional high-frequency power detector corrects only the temperature characteristic and the frequency characteristic. However, in the conventional radio transmission apparatus and the like, there was no particular problem because only a single carrier signal of a narrow band signal was amplified. . However, in recent years, for example, in a wireless transmission apparatus for W-CDMA, the frequency band of one carrier is expanded, and multicarrier transmission is performed. Therefore, in addition to the frequency characteristics for a single carrier, the influence of multi-carrier due to carrier distribution in a wide band cannot be ignored.
[0004]
This will be described with reference to FIGS. FIG. 14 shows a conventional high-frequency power detection circuit. In the figure, 1 is a high-frequency signal input terminal, 2 is a directional coupler, 3 is a detection circuit for detecting a high-frequency signal, 9 is a temperature sensor, and 5 is an output characteristic of the detection circuit 3 based on the output of the temperature sensor 9. Is a reverse characteristic generation circuit that generates an output with reverse characteristics, and 6 is a synthesis circuit that combines the output of the detection circuit 3 and the output of the reverse characteristic generation circuit 5 to obtain high-frequency power detection that is less affected by temperature changes. The output of the synthesis circuit 6 is used as detection power.
[0005]
When a wideband signal of a W-CDMA signal is input from the high frequency signal input terminal 1 to this conventional high frequency power detection circuit, the output power and temperature of the detection circuit 3 using the carrier pattern (1 Carr to 5 Carr) as parameters. When the relationship is actually measured, the input / output characteristics as shown in FIG. 15 are shown. As can be seen from FIG. 15, in the conventional high-frequency power detection circuit of FIG. 14, even if the temperature characteristic can be compensated, a detection error due to the carrier pattern occurs. FIG. 15 is a graph of actual measurement values when an analog device AD8361 is used as a detection circuit, the center frequency is 2140 MHz, and the detection circuit input is 0 dBm.
[0006]
[Problems to be solved by the invention]
As described above, the conventional high frequency power detection circuit has a detection error in the detection power due to the carrier pattern. The present invention is intended to provide a high-frequency power detection circuit with high measurement accuracy without being affected by the multi-carrier.
[0007]
[Means for Solving the Problems]
The high-frequency power detection circuit according to the present invention receives a high-frequency signal from a multi-carrier high-frequency power source and generates an output corresponding to the power of the input signal according to the carrier pattern of the multi-carrier high-frequency signal. An inverse characteristic generation circuit that generates a signal for correcting the characteristic of the detection circuit, and a synthesis circuit that corrects and extracts the output of the detection circuit with the output of the reverse characteristic generation circuit. .
[0008]
In the high-frequency power detection circuit described above, the inverse characteristic generation circuit outputs a signal whose correction amount is corrected according to the output level of the detection circuit.
[0009]
In the high-frequency power detection circuit described above, carrier pattern information is extracted from a communication line for multi-carrier high-frequency signals.
[0010]
The high-frequency power detection circuit described above includes a carrier information detection circuit that detects carrier pattern information from a multicarrier high-frequency signal.
[0011]
In the high-frequency power detection circuit described above, the inverse characteristic generation circuit includes a correction value of the detection circuit output for the carrier pattern information measured in advance as a table.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a block diagram showing a high-frequency power detection circuit according to Embodiment 1 of the present invention. In the figure, 1 is a high-frequency signal input terminal, 2 is a directional coupler, 3 is a detection circuit for detecting a high-frequency signal, 4 is a signal received from the external device 7, and carrier information, that is, the carrier pattern to which the received signal belongs The carrier information receiving circuit for extracting the information, 5 is an inverse characteristic generating circuit for generating a signal for correcting the output characteristic of the detecting circuit 3 based on the output of the carrier information receiving circuit 4, and 6 is the output of the detecting circuit 3. The output of the synthesis circuit 6 is combined with the output of the inverse characteristic generation circuit 5 to obtain high-frequency power with reduced influence of errors caused by the carrier pattern. The output of the synthesis circuit 6 is used as detected power.
[0013]
Next, a carrier pattern that affects the input / output characteristics of the detection circuit 3 will be described with reference to FIGS. In the W-CDMA signal, 2110 MHz to 2170 MHz (bandwidth 60 MHz) is divided into three bands of L, M, and H every 20 MHz. Carriers F1 to F4 every 5 MHz are multiplexed in a maximum of 4 waves in each 20 MHz band. The carrier patterns, which are the parameters in FIG. 15 described above, include five patterns of 1 Carr to 5 Carr. Each carrier pattern is shown in FIG. 3, and the position on the frequency axis of the carrier is shown in FIG.
[0014]
Next, the operation will be described. A part of the high frequency signal input from the high frequency signal input terminal 1 is input to the detection circuit 3 via the directional coupler 2. The carrier information receiving circuit 4 receives a signal from the external device 7 and outputs carrier pattern information (that is, a signal indicating which of the carrier patterns 1 to 5 in FIG. 3), and an inverse characteristic generating circuit based on the carrier pattern 5 is driven. The inverse characteristic generation circuit 5 outputs a correction output signal having a characteristic opposite to the output characteristic of the detection circuit 3 according to the carrier pattern, and the synthesis circuit 6 corrects the output of the detection circuit 3.
[0015]
FIG. 3 shows carrier patterns 1 to 5 and correction values corresponding to the carrier patterns. This correction value is measured in advance and stored in the memory table of the inverse characteristic generation circuit 5. The inverse characteristic generation circuit 5 outputs a correction output signal corresponding to the correction value, and is combined with the output of the detection circuit 3 by the combining circuit 6. The output of the synthesis circuit 6 is shown in FIG. As described above, the output of the detection circuit 3 before correction in FIG. 14 varies as shown in FIG. 15 with respect to the carrier pattern and temperature. FIG. 15 shows that there are fluctuations due to the carrier pattern in addition to the temperature characteristics. Thus, in FIG. 15 in which carrier pattern correction is not performed, the carrier pattern deviation of 0.2 dBm or more can be suppressed to 0.1 dBm or less according to the present embodiment as shown in FIG. An output from which the influence of the pattern is removed can be obtained.
[0016]
Since the high-frequency power detection circuit configured as described above can minimize errors in the detection circuit due to the carrier pattern, it enables highly accurate power detection for a wideband modulation signal such as W-CDMA. .
[0017]
Embodiment 2. FIG.
5 is a block diagram of a high frequency power detection circuit according to Embodiment 2 of the present invention. In the figure, reference numeral 5a denotes an inverse characteristic generation circuit controlled by the output level of the detection circuit 3. The other elements are denoted by the same reference numerals as those in FIG.
[0018]
A part of the high-frequency signal input from the high-frequency signal input terminal 1 is input to the detection circuit 3 via the directional coupler 2. Carrier information is input from the external device 7 to the carrier information receiving circuit 4. The inverse characteristic generation circuit 5a receives a signal indicating the detection output level of the detection circuit 3 in addition to the carrier pattern information, and generates a correction signal according to this level and the carrier pattern. In the inverse characteristic generation circuit 5a, a correction coefficient is recorded on the memory table, and an inverse characteristic output is generated according to the carrier information and the detection circuit output level.
[0019]
The operation of the inverse characteristic generation circuit 5a will be described with reference to FIGS. FIG. 6 is a block diagram of the inverse characteristic generation circuit 5a, which includes an inverse characteristic table 17, an amplitude error table 21, and a D / A converter 19. FIG. 7 shows the recorded contents of the reverse characteristic table 17 of the reverse characteristic generation circuit 5a.
[0020]
The carrier information reception circuit 4 receives a signal from the external device 7, and outputs band information (L, M, H) and carrier pattern information to the inverse characteristic generation circuit 5a. The reverse characteristic table 17 in the reverse characteristic generation circuit 5a outputs the reverse characteristic correction value 18 using the band information and the carrier pattern information as arguments. This is shown in FIG. In the reverse polarity table 17, a total of 45 correction value data are recorded in advance, with three bands L, M, and H and 15 carrier patterns. A signal output from the amplitude error table 21 is further added to the inverse characteristic correction value 18 in accordance with the detection output level, and a signal D / A converted by the D / A converter 19 is output.
[0021]
For comparison, FIG. 8 shows the input / output characteristics with respect to the temperature of the detection circuit output when a wideband signal of a W-CDMA signal is input to the conventional high-frequency power detection circuit, using the carrier pattern as a parameter. The data of this graph is an actual measurement value using an AD8361 manufactured by Analog Devices as the detection circuit 3, the center frequency being 2140 MHz, and the detection circuit input level = −10 dBm.
[0022]
FIG. 8 differs from the first embodiment (input level = 0 dBm, FIG. 4) in output characteristics. Therefore, as shown in FIG. 3, when a correction value for the input level of 0 dBm is generated in the inverse characteristic generation circuit 5a and correction is performed thereby, the result is as shown in FIG. In FIG. 9, the deviation between the carrier patterns is increased as compared with FIG. 8 without correction. This is because the detection circuit characteristic is affected by the carrier pattern and the input level, and in order to eliminate this, the reverse characteristic generation is performed so that a signal corresponding to the output level of the detection circuit 3 is supplied to the reverse characteristic generation circuit 5a. The circuit 5a is configured as shown in FIG. 6, and its output is determined by the carrier pattern and the detection output level from the detection circuit 3. The output of the inverse characteristic generation circuit 5a is combined with the output of the detection circuit 3 by the combining circuit 6. The obtained corrected power detection circuit characteristics are shown in FIG .
[0023]
The high-frequency power detection circuit configured as described above can minimize the detection error of the detection circuit output, and can perform optimal power detection even for a wide band of a wireless communication power amplifier.
[0024]
Embodiment 3 FIG.
FIG. 11 is a block diagram of a high-frequency power detection circuit according to Embodiment 3 of the present invention. In the figure, reference numeral 20 denotes a directional coupler that extracts a part of a signal from the high-frequency signal input terminal 1, and 10 is a carrier information detection circuit that extracts carrier information from the output of the directional coupler 20. Other elements are denoted by the same reference numerals as those in FIG.
[0025]
A part of the high-frequency signal input from the high-frequency signal input terminal 1 is input to the detection circuit 3 via the directional coupler 2. The carrier information detection circuit 10 detects carrier information from a signal obtained by taking out a high-frequency signal input from the high-frequency signal input terminal 1 by the directional coupler 20. The inverse characteristic generation circuit 5a generates an inverse characteristic signal according to the carrier information obtained by the carrier information detection circuit 10. The reverse characteristic generation circuit 5a records the correction value on the memory table and generates a reverse characteristic signal according to the carrier information.
[0026]
FIG. 12 is a block diagram of the carrier information detection circuit 10. Reference numeral 11 denotes a frequency converter that converts the frequency of the high-frequency signal with the output of the frequency variable oscillator 12, reference numeral 13 denotes a band-pass filter (BPF) connected to the output side of the frequency converter 11, and reference numeral 14 detects the output of the band-pass filter 13. A detection circuit 15 is a control circuit. Reference numeral 16 denotes carrier pattern information to be output to the next stage inverse characteristic generation circuit 5a.
[0027]
Next, the operation will be described. The high frequency signal input to the carrier information detection circuit 10 is mixed with the output of the frequency variable oscillator 12 by the frequency converter 11 and output to the band pass filter 13. The band-pass filter 13 has a bandwidth of 5 MHz and extracts a signal having a bandwidth of one carrier of the W-CDMA signal. The detection circuit 14 detects the output of the band pass filter 13 and converts it into a DC component. The control circuit 15 determines the presence or absence of a signal based on the output of the detection circuit 14. The control circuit 15 detects the carrier pattern by determining the output of the detection circuit 14 while setting the oscillation frequency of the variable frequency oscillator 12 to the center frequency of each carrier shown in FIG. The detected carrier pattern information 16 is output to the inverse characteristic generation circuit 5a. As described above, carrier pattern information is extracted from the high-frequency signal.
[0028]
The carrier information detection method will be described using the flowchart of FIG. First, the oscillation frequency of the frequency variable oscillator 12 is set for the carrier L1 of the band L (20L). On the other hand, the presence or absence of the output of the detection circuit 14 is determined (21L). If there is a detection output, a carrier flag is set (22L). The above operation is repeated four times with F1, F2, F3, and F4 until the band L ends (23L). When the band L ends, it is checked whether at least one carrier flag is set (24L). If set, the carrier pattern information 16 is output to the inverse characteristic generation circuit 5a (25). If not set, the same operation as that performed for the band L is performed for the bands M and H (20M to 24M and 20H to 24H).
[0029]
As described above, the configuration of the present embodiment having the carrier information detection circuit 10 can detect the high-frequency signal power with high accuracy by directly obtaining the carrier information from the high-frequency signal.
[0030]
In the description of the first to third embodiments, the description of the temperature correction of the detector output by the temperature sensor is omitted, but it goes without saying that the temperature correction is performed as necessary.
[0031]
【The invention's effect】
As described above, according to the present invention, the output of the detection circuit that detects the monitor power from the high frequency source is provided with the circuit that corrects the carrier information, so that it is suitable for a wideband signal free from errors due to the carrier pattern. A high frequency power detection circuit can be obtained.
[0032]
In addition, since the correction amount is determined by the output level of the detector together with the carrier information, a high-accuracy high-frequency power detection circuit can be obtained.
[0033]
In addition, since carrier information is obtained from a communication line using a carrier information detection circuit, a high-frequency power detection circuit with high accuracy can be obtained with a simple configuration.
[0034]
Further, by recording the correction values as a table in the reverse characteristic generation circuit, an accurate correction amount can be easily obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a high frequency power detection circuit according to a first embodiment of the present invention.
FIG. 2 is a carrier arrangement diagram of W-CDMA.
FIG. 3 is a diagram showing a carrier pattern and a correction value for the carrier pattern.
FIG. 4 is a diagram showing input / output characteristics of a high-frequency power detection circuit according to the first embodiment.
FIG. 5 is a block diagram showing a high frequency power detection circuit according to a second embodiment of the present invention.
FIG. 6 is a block diagram illustrating an inverse characteristic generation circuit according to the second embodiment.
FIG. 7 is a diagram illustrating the contents of an inverse characteristic table of the inverse characteristic generation circuit according to the second embodiment.
FIG. 8 is a diagram showing input / output characteristics of a high-frequency power detection circuit for explaining the operation of the second embodiment.
FIG. 9 is a diagram showing input / output characteristics of a high-frequency power detection circuit for explaining the operation of the second embodiment.
FIG. 10 is a diagram showing input / output characteristics of a high frequency power detection circuit according to the second embodiment.
FIG. 11 is a block diagram showing a high frequency power detection circuit according to a third embodiment of the present invention.
12 is a block diagram showing a carrier information detection circuit in Embodiment 3. FIG.
FIG. 13 is a flowchart for explaining the operation of the carrier information detection circuit according to the third embodiment.
FIG. 14 is a block diagram showing a conventional high-frequency power detection circuit.
FIG. 15 is a diagram showing input / output characteristics of a conventional high-frequency power detection circuit.
[Explanation of symbols]
1 high frequency input terminal, 2 directional coupler,
3 detection circuit, 4 carrier information reception circuit,
5 reverse characteristic generation circuit, 5a reverse characteristic generation circuit,
6 synthesis circuit, 7 external device,
10 carrier information detection circuit, 11 frequency converter,
12 frequency variable oscillator, 13 band pass filter,
14 detection circuit, 15 control circuit,
16 carrier pattern information, 17 reverse characteristic table,
18 Reverse characteristic correction value, 19 D / A converter,
20 Directional coupler, 21 Amplitude error table.

Claims (4)

A detection circuit that receives a high-frequency signal from a multi-carrier high-frequency power source and generates an output corresponding to the power of the input signal, and a table that stores correction values of the detection circuit output for carrier pattern information measured in advance the inverse characteristic generating circuit for generating a signal for correcting the characteristics of the detection circuit in response to the carrier pattern of the multicarrier RF signal, the combining circuit extracting an output of the detection circuit is corrected by the output of the inverse characteristic generation circuit And a high-frequency power detection circuit.   2. The high frequency power detection circuit according to claim 1, wherein the inverse characteristic generation circuit outputs a signal whose correction amount is corrected according to an output level of the detection circuit.   3. The high frequency power detection circuit according to claim 1, wherein carrier pattern information is extracted from a communication line for multicarrier high frequency signals.   4. The high frequency power detection circuit according to claim 3, further comprising a carrier information detection circuit for detecting carrier pattern information from a multicarrier high frequency signal.

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