JPH11344518A - Power detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce detection errors and the burden of adjustment work. SOLUTION: A detection circuit 11 detects an RF signal outputted from a power amplifier 8 by diode detection and a DC detection voltage indicating an amplitude value is outputted. After partially pressured by a partial pressure circuit 12, this detection voltage is A/D-converted by an A/D converter 13 to be converted into an amplitude value detection data Y. A calculation circuit 14A approximates the relationship between the output of the A/D converter 13 and the output power of the power amplifier 8 with an exponential function, calculates a transmitted power, and allows a power indicator 15 to indicate it. A coefficient of the exponential function used by the calculation circuit 14A is rewritably stored in a memory 16A. According to an adjustment operation with an adjustment panel 17A in advance, a parameter modifying circuit 18A adjusts errors of the output power of the power amplifier 8 and the output value of the calculation circuit 14A to become minimal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power detection apparatus, and more particularly to a power detection apparatus suitable for detecting a transmission power of a transmitter.

[0002]

2. Description of the Related Art In order to display transmission power, a transmitter detects an amplitude value of an RF signal (voltage signal) extracted from an output of a power amplifier and converts the amplitude value into a power value by a predetermined conversion formula. Some have a transmission power detection / display function of displaying and displaying. FIG. 7 shows a configuration of an FM type transmitter having a transmission power detection / display function. The audio signal input by the microphone 1 is FM-modulated by the modulator 2 and then converted by the frequency converter 3 into an RF signal of a desired transmission frequency. The transmission frequency is changed by the frequency control unit 5 performing frequency control on the frequency conversion unit 3 according to the frequency variable operation by the frequency variable operation unit 4. The level of the RF signal output from the frequency conversion unit 3 is changed in accordance with the output variable operation performed by the output variable operation unit 7 by the level variable unit 6, and then the power is amplified by the power amplification unit 8. Then, it is sent to the transmission antenna 9 and radiated outside.

On the output side of the power amplifying section 8, a transmission power detecting / displaying section 10 is provided. This transmission power detection
The display unit 10 receives a part of the RF signal output from the power amplification unit 8 by a coupling circuit, detects an amplitude value by performing linear detection by diode detection, and outputs a DC detection voltage representing the amplitude value. A detecting circuit 11, a voltage dividing circuit 12 for dividing a detection voltage output from the detecting circuit 11 at a predetermined voltage dividing ratio, and an output of the voltage dividing circuit 12 having a quantization bit number of 8 bits and a 256-step amplitude of 0 to 255. From the relationship between the power P and the voltage V (P = V ² / R), the transmission power T _POWER , which is the output power of the power amplifying unit 8, is obtained from the A / D converter 13 that quantizes the value detection data Y. It has a calculation circuit 14 for calculating by approximation with a broken line function based on the amplitude value detection data Y, and a power display 15 for digitally displaying the value of the transmission power calculated by the calculation circuit 14.

[0004] For detection circuit 11 that the diode detection, but the detection characteristic becomes as code A ₁ in FIG. 8, the forward voltage of the diode - variations in current characteristics, the variation of the circuit configuration such as variations in the coupling circuit As a result, the detection characteristics change as indicated by reference signs A ₁ , A ₂ , and A ₃ in FIG. 8, and a difference occurs in the detection efficiency for each circuit. Therefore, the calculation circuit 14 cancels the difference in the detection efficiency due to the variation in the circuit configuration.
As shown in, the line segment E ₁ of the Y-T domain in the coordinate system is 0 ≦ Y ≦ y _1, domain is y ₁ <Y ≦ y ₂ line segments E _2, domain is y ₂ <a Y The approximate calculation of the transmission power T _POWER is performed by using a polygonal line composed of the line segment E ₃ , and E ₁ , E ₂ , and E ₃ are adjusted for each circuit.

The equation of a straight line representing the line segment E ₁ in FIG. 9 is as follows: T = e ₁ · Y (1) e ₁ = T ₁ / y ₁ where 0 ≦ Y ≦ y ₁ and the line segment E ₁ The equation of a straight line representing ₂ is as follows: Te ₁ · y ₁ = e ₂ · (Y−y ₁ ) · (2) e ₂ = (T ₂ −T ₁ ) / (y ₂ −y ₁ ) y ₁ <Y ≦ y ₂ , and the equation of a straight line representing the line segment E ₃ is T- {e ₂ · (y ₂ −y ₁ ) + e ₁ · y ₁ } = e ₃ · (Y−y ₂ ) (3) e ₃ = (T ₃ −T ₂ ) / (y ₃ −y ₂ ) where y ₂ <Y.

The diode detection of each detection circuit 11 is performed in advance.
Coefficient e according to wave characteristics₁, E_Two, E _ThreeAnd coordinates y₁, Y_Two
Are set, and these e₁~ E_ThreeAnd y₁, Y_TwoDetermined
By using a line function on the Y-T coordinate, the input amplitude
Transmission power T according to value X_{PO WER}To ask.
Coefficient e that determines each line segment₁, E_Two, E_ThreeAnd coordinates y₁, Y_Two
, And an appropriate initial value of the parameter,
It is stored in the memory 16 in a rewritable manner,
The calculation circuit 14 can read the parameters stored in the
And

[0007] Then, instead of the microphone 1, a standard signal generator is connected to the transmitter to input a standard signal having a constant amplitude and a constant frequency, and a power meter with a dummy load is connected instead of the transmitting antenna 9. . The frequency variable operation unit 4 is operated to set the transmission frequency for adjustment. First, the adjustment panel 17 is set to the first adjustment mode. At this time, the parameter change circuit 18 becomes rewritable for e ₁ and y ₁ in the memory 16, and the calculation circuit 14 performs calculation processing using e ₁ in the memory 16 according to the equation (1).

[0008] The output variable operation section 7 is operated so that the power meter has a predetermined power value T ₁ (> 0), and y ₁ is registered on the adjustment panel 17. Then, the parameter changing circuit 18 updates rewrites the y ₁ of the memory 16 the amplitude value detection data output from the A / D converter 13 at that time. Subsequently, when the variable operation of e ₁ in adjustment panel 17, the parameter changing circuit 18 updates the e ₁ of the memory 16 in accordance with the operation.

The calculation circuit 14 uses the updated e ₁ to calculate
The correction processing is performed according to the equation (1). Stop variable operation of e ₁ when the display of the power indicator 15 showed T _1. Thus completes the adjustment of parameters of the line segment E _1. Next, the adjustment panel 17 is set to the second adjustment mode. At this time, the parameter change circuit 18 stores e ₂ and y in the memory 16.
₂ can be rewritten, and the calculation circuit 14 performs a calculation process according to the equation (2) using e ₁ , e ₂ , and y ₁ of the memory 16. By operating the output variable operation unit 7 so that the power meter has a predetermined power value T ₂ (> T ₁ ), y ₂ is registered on the adjustment panel 17. Then, the parameter change circuit 18 rewrites and updates y ₂ in the memory 16 with the amplitude value detection data output from the A / D converter 13 at that time. Then, when the variable operation e ₂ in adjustment panel 17, the parameter changing circuit 18 updates the e ₂ of the memory 16 in accordance with the operation.

The calculation circuit 14 performs a correction process in accordance with (2) using the updated e ₂ and e ₁ and y ₁ adjusted in the first adjustment mode. Stop variable operation e ₂ when the display of the power indicator 15 showed T _2. Thus, the line segment E
Adjustment of ₂ is completed. Next, the third adjustment mode is set on the adjustment panel 17. At this time, the parameter change circuit 18
Allows rewriting of e ₃ of the memory 16, and the calculation circuit 14 calculates e ₁ , e ₂ , e ₃ , y ₁ , y ₂ of the memory 16
Is used to perform calculation processing according to equation (3). By operating the output variable operation unit 7, the power meter is set to a predetermined power value T ₃ (>
T ₂ ) (at this time, the amplitude value detection data output from the A / D converter 13 is y ₃ in FIG. 9),
When a variable operation e ₃ in the adjustment panel 17, the parameter changing circuit 18 updates the e ₃ of the memory 16 in accordance with the operation.

The calculation circuit 14 updates e ₃ , e ₁ , y ₁ , and e ₁ adjusted in the first adjustment mode and the second adjustment mode.
Correction processing is performed according to (3) using e ₂ and y ₂ . Stop variable operation e ₃ when the display of the power indicator 15 showed T _3. Thus, the adjustment of the line segment E ₃ is completed. Thereafter, when the adjustment mode is canceled by the adjustment panel 17 and the set is shifted to the normal operation mode, the calculation circuit 14 inputs the data from the A / D converter 13 while referring to the parameters stored in the memory 16. According to the value of the amplitude value detection data Y, in the range of 0 ≦ Y ≦ y ₁ , the transmission power T _POWER is calculated from Y according to the equation (1), and y ₁ <Y ≦ y
_In the range of ₂ , transmission power T _POWER from Y according to equation (2)
Is calculated, and in the range of y ₂ <Y, the transmission power T _POWER is calculated from Y according to the equation (3). As a result, the detection circuit 11
Irrespective of the variation in the detection characteristics of the above, the transmission power T _{POWER with} a small error can be calculated.

[0012]

However, in the above-described conventional method for calculating the transmission power value, the relationship between Y and T is approximated by a polygonal line composed of E ₁ , E ₂ , and E _{3 in} FIG.
Each adjustment point _{(y 1, T 1),} (y 2, T 2), (y
Although the error is small at ₃ and T ₃ ), the display error of the transmission power T _POWER becomes large between the adjustment points. Further, there is a problem that the number of parameter items to be adjusted becomes very large, and the burden of the adjustment work is large.

As another problem, since the detection characteristics of the detection circuit 11 change depending on the frequency, there is a problem that an error increases when the transmission circuit is operated at a transmission frequency different from the frequency of the reference signal generated in the adjustment operation. there were. The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide a power detection device that can reduce an error at points other than an adjustment point and reduce the burden of an adjustment operation. Also,
It is an object of the present invention to provide a power detection device in which an error does not increase even if the frequency changes.

[0014]

In the power detection apparatus according to the first aspect of the present invention, detection means (11, 12) for detecting an AC signal taken from an arbitrary point of a device or a circuit to be detected and detecting a level. , 13), the power of any target point of the detection target device or circuit is approximated by an exponential function of the detection means output, and the power detection means (14A, 16A) for outputting the power and the exponential function of the power detection means are output. Adjustment means (17A, 18A) for adjusting the coefficient so that an error between the power of an arbitrary point of the detection target device or the circuit and the output value of the power detection means is reduced.

The detecting means detects an AC signal taken from an arbitrary point, such as in the middle of an apparatus or circuit to be detected or an output point, to detect a level, and the power detecting means detects an arbitrary point (AC) of the apparatus or circuit to be detected. (It may be the same as or different from the point from which the signal was extracted.) The power is approximated by an exponential function of the detection means output and output. The coefficient of the exponential function is adjusted in advance by the adjusting unit so that the error between the power of the arbitrary target point of the device or the circuit to be detected and the output value of the power detecting unit is reduced. As a result, the detection means performs linear detection by diode detection or the like, and the relationship between power and voltage (P = V ²
/ R), the relationship between the output of the detection means and the power of the detection target point of the detection target device or circuit is a quadratic function, or the detection means performs exponential function detection other than linear detection, and detects the output of the detection means. When the relation with the power of the detection target point of the target device or circuit is an exponential function other than a quadratic function, power detection with a small error can be performed. In addition, since it is only necessary to adjust the coefficient of the exponential function, the number of adjustment steps is small, and the adjustment work is simple.

In the power detection apparatus according to a second aspect of the present invention, the detection means (1) detects an AC signal taken from an arbitrary point of a device or a circuit to be detected and detects a level.
1, 12, 13) and the power of any target point of the detection target device or circuit are approximated by an exponential function of the detection means output, and at this time, the exponential function is adjusted according to the detection characteristics of the detection means for each frequency. And a power detection unit (14B, 16B) that outputs a power value obtained by approximating by an exponential function according to the frequency of the AC signal.

The detecting means detects the level by detecting an AC signal taken from an arbitrary point of the device or circuit to be detected, and the power detecting means detects the power of an arbitrary point of the device or circuit to be detected. Approximately calculated by an exponential function. At this time, a plurality of exponential functions are prepared for each frequency in accordance with the frequency-dependent detection characteristics of the detection means, and the power obtained by approximating the exponential function according to the frequency of the AC signal. Output the value. As a result, correction can be performed with a small error even in a detection unit whose detection characteristics change with frequency, such as diode detection.

According to a third aspect of the present invention, there is provided the power detecting device according to the second aspect, wherein
B, 16B)
Adjustment means (17B, 18B) for adjusting an error between the power of an arbitrary target point of the detection target device or circuit and the output value of the power detection means for each frequency is provided. As a result, power detection with a small error can be performed irrespective of variations in the input / output characteristics of the detection means, and the adjustment operation can be simplified.

According to a fourth aspect of the present invention, there is provided the power detecting device according to the third aspect, wherein the power detecting means (14) is provided.
B, 16B) output an electric power value by using an exponential function interpolated from two exponential functions having frequencies close to the AC signal when the frequency of the AC signal does not match the prepared exponential function; It is characterized by. Thus, no matter how the frequency of the AC signal changes, power detection with little error can be performed.

[0020]

Next, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an FM type transmitter having a transmission power detection / display function according to the present invention, and the same components as those in FIG. 7 are denoted by the same reference numerals. On the output side of the power amplification unit 8, a transmission power detection / display unit 10A is provided. The transmission power detection / display unit 10A inputs a part of the RF signal (here, a voltage signal) output from the power amplification unit 8 by a coupling circuit, detects an amplitude value by diode detection, and detects the amplitude value. A detection circuit 11 that outputs a detected DC voltage, a voltage division circuit 12 that divides the detection voltage output from the detection circuit 11 at a predetermined voltage division ratio, and an output of the voltage division circuit 12 that has 8 quantization bits. An A / D converter 13 that quantizes to 256-level amplitude value detection data Y of 0 to 255 and an amplitude value detection data Y output from the A / D converter 13 have a linear detection method in a detection circuit 11. In the case of exponential function detection other than detection or linear detection, from the relationship between power and voltage (P = V ² / R), the amplitude value detection data Y and the transmission power T _POWER which is the output power of the power amplification unit 8 have an exponential function. The relationship Et al., The calculation circuit 14A which calculates the transmit power T _POWER from the amplitude detection data Y by a predetermined exponential function and outputs the calculation circuit 1
A power indicator 15 for digitally displaying the value of the transmission power calculated in 4A, a memory 16A in which a coefficient of an exponential function used for calculation by the calculation circuit 14A is rewritably stored as a parameter, and an adjustment for performing an adjustment operation. It comprises a panel 17A and a parameter change circuit 18A for rewriting and changing parameters stored in the memory 16A in accordance with an adjustment operation on the adjustment panel 17A.

Since the detection circuit 11 performs linear detection or exponential function detection other than linear detection using diode detection, variations in forward voltage-current characteristics of diodes, variations in coupling circuits for inputting RF signals, etc. by variation of the circuit configuration of the detection circuit 11, as the code a _1, a _2, a ₃ in FIG. 8 to the detection characteristics, a difference in detection efficiency. For this reason, when the transmission power value is obtained from the amplitude value detection data Y output from the A / D converter 13 using a fixed exponential function, an error is generated based on the difference in the detection efficiency of the detection characteristics. The calculation circuit 14A suppresses the error by performing power calculation using an exponential function having a corrected coefficient so as to cancel the difference in detection efficiency generated in the detection circuit 11.

Specifically, the input amplitude value X of the detection circuit 11
And the amplitude value detection data Y output from the A / D converter 13
Y = aX ⁿ (4) where a is approximated by an n-order function of the coefficient (see FIG. 2). At this time, X = (Y / a) ^{1 / n} , and from the relationship between power and voltage (P = V ² / R), the transmission power T _POWER which is the output power of the power amplification unit 8 is given by T _POWER = bX ² = B ｛(Y / a) ^{1 / n} ｝ ² = b (Y / a) ^{2 / n} = cY ^{2 / n} (5) where b and c are approximated by an exponential function of Y in the form of coefficients. (See FIG. 3).

A good approximation can be obtained by setting n in equations (4) and (5) to, for example, 1 for linear detection and 2 for square detection. Depending on the detection method, n can be other than 1 or 2, and n is not limited to an integer, but a small number or a fraction may be used. FIG. 2 shows a case where the detection characteristic viewed between the input of the detection circuit 11 and the output of the A / D converter 13 is approximated by a linear function when approximated by a linear function and by an n-dimensional function other than linear. 3 shows an approximate curve. If n is fixed, the only adjustment item in equation (5) is c.

First, an appropriate initial value of the coefficient c in the equation (5) is rewritably stored in the memory 16A, and the output power of the power amplifying unit 8 and the calculation circuit 1 are adjusted through the adjustment process.
At 4A, correction is made so that the error from the calculated transmission power T _{POWER in} accordance with equation (5) is minimized. Adjustment panel 17A
, The coefficient c stored in the memory 16A can be changed. When the variable operation of the coefficient c is performed on the adjustment panel 16A in the adjustment mode, the parameter change circuit 18A rewrites c in the memory 16A according to the operation. Other components of the transmission power detection / display unit 10A and other components of the transmitter are configured exactly the same as those in FIG.

Next, the operation of the above embodiment will be described. It is assumed that n in the equations (4) and (5) is fixed to a predetermined value determined by the detection method in the detection circuit 11. For example, n = 1 for linear detection and n = 2 for squared detection. It is assumed that an appropriate initial value of the coefficient c in the equation (5) is stored in the memory 16A in advance.

First, a method of adjusting the coefficient c for canceling the variation in the circuit configuration of the detection circuit 11 will be described.
A standard signal generator is connected to the transmitter in place of the microphone 1 to input a standard signal having a predetermined constant amplitude and a predetermined frequency, and a power meter with a dummy load is connected in place of the transmission antenna 9. The transmission frequency is set to a predetermined value by operating the frequency variable operation unit 4. The standard signal is the modulator 2
After that, the frequency is converted into an RF signal of the set transmission frequency by the frequency conversion unit 3. The RF signal is supplied to the level variable unit 6
Then, the power is amplified by the power amplifying unit 8. When the adjustment mode key of the adjustment panel 17A is pressed to set the adjustment mode, the parameter change circuit 18A can rewrite the coefficient c of the memory 16A, and the calculation circuit 14A uses the coefficient c of the memory 16A according to the equation (5). The transmission power T _POWER is calculated from the amplitude value detection data Y.

Next, the output variable operation section 7 is operated so that the power meter becomes a predetermined reference value T ₀ (> 0) for adjustment (the value of the amplitude value detection data Y at this time is shown in FIG. 3). It is shown in the y ₀ of). In this state, when the coefficient variable key is pressed on the adjustment panel 17A to perform the variable operation of c, the parameter changing circuit 1
8A updates c of the memory 16A according to the operation. The calculation circuit 14A performs a calculation process using the updated c according to the equation (5). Stop variable operation c when the display of the power indicator 15 showed T _0. Thereafter, the adjustment mode is released by pressing the adjustment mode release key on the adjustment panel 17A, and the set is shifted to the normal operation mode. In the normal operation mode, even if the variable coefficient key is operated on the adjustment panel 17A, it is ignored by the parameter change circuit 18A. Thereby, the adjustment of the coefficient is completed, and the error between the power value of the RF signal output from the power amplification unit 8 and the output value of the calculation circuit 14A is reduced.

Next, the operation in the normal operation mode will be described. With the microphone 1 and the transmission antenna 9 connected, the audio signal input to the microphone is FM-modulated by the modulation unit 2, and then the RF signal of the transmission frequency corresponding to the operation of the frequency variable operation unit 4 by the frequency conversion unit 3. Converted to a signal. Then, after being changed to a level corresponding to the operation of the output variable operation unit 7 by the level variable unit 6, the power is amplified by the power amplification unit 8 and radiated from the transmission antenna 9.

The transmission power varies according to the operation of the output variable operation unit 7, and is detected and displayed by the transmission power detection / display unit 10A. That is, a part of the RF signal output from the power amplification unit 8 is input to the detection circuit 11 and diode-detected, and a detection voltage indicating an amplitude value is output.
The detected voltage is divided by a voltage dividing circuit 12 into a predetermined voltage dividing ratio, then quantized by an A / D converter 13 into 8 bits, and output as amplitude value detection data Y. When linear detection is performed, there is linearity between the input amplitude value X of the detection circuit 11 and the amplitude value detection data Y output from the A / D converter 13, and nonlinear detection is performed. In this case, there is an exponential non-linearity expressed by the expression (4) (n ≠ 1) between X and Y (see FIG. 2).

The calculation circuit 14A uses the adjusted coefficient c stored in the memory 16A to calculate the transmission power T from the amplitude value detection data Y by the exponential function of equation (5) (see FIG. 3).
_{POWER R} is calculated and output to the power display 15 for digital display.

According to this embodiment, the detection circuit 11 performs linear detection by means of diode detection, square detection, or the like, and looks between the input of the detection circuit 11 and the output of the A / D converter 13. When the detection characteristic can be approximated by an exponential function, the relationship between the output of the A / D converter 13 and the transmission power can be well approximated using an exponential function from the relationship between power and voltage (P = V ² / R). , Power detection with a small error can be performed, and accurate display of transmission power can be performed. Further, the coefficient parameter of the exponential function can be adjusted by setting the adjustment mode on the adjustment panel 17A. However, since there is only one adjustment item of the coefficient c, the number of adjustment steps is small, and the work can be simplified.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of an FM-type transmitter having a transmission power detection / display function according to the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. On the output side of the power amplification unit 8, a transmission power detection / display unit 10B is provided. In the transmission power detection / display unit 10B, since the detection characteristic of the detection circuit 11 that performs diode detection varies depending on the frequency, when the variable range of the transmission frequency of the wireless device is wide, optimal correction according to the transmission frequency can be performed. The display error of the transmission power is reduced regardless of the transmission frequency.

When the lower limit of the variable range of the transmission frequency is f _L , the upper limit is f _H , and the center is f _C , the input amplitude value X of the detection circuit 11 and the output from the A / D converter 13 when the frequency is f _L. that the relationship between the amplitude detection data ^{_{Y, Y = a L X n}} ·· (6) where, a _L is approximated by the n-th order exponential coefficient (see FIG. 5). At this time, X = (Y / a _L ) ^{1 / n} . From the relationship between power and voltage (P = V ² / R), the transmission power T _POWER which is the output power of the power amplifying unit 8 is expressed as T _POWER = b ^{_{L X 2 = b L {(}} Y / a L) 1 / n} 2 = b L (Y / a L) 2 / n = c L Y 2 / n ·· (7) where, b _L, c _L is The coefficient can be approximated by an exponential function of Y (see FIG. 6).

The detection circuit 11 when the frequency is f _C
The relationship between the input amplitude value X and the amplitude value detection data Y output from the A / D converter 13 is as follows: Y = a _C X ⁿ ··· (8) where a _C is approximated by an n-th exponential function of the coefficient (See FIG. 5). At this time, X = (Y / a _C ) ^{1 / n} , and from the relationship between power and voltage (P = V ² / R), the transmission power T _POWER is given by T _POWER = b _C X ² = b _C ｛(Y / a _C ) ^{1 / n} ｝ ² = b _C (Y / a _C ) ^{2 / n} = c _C Y ^{2 / n} (9) where b _C and c _C are approximated by an exponential function of Y, such as coefficients. (See FIG. 6).

Furthermore, the detection circuit when the frequency is f _H 11
The relationship between the input amplitude value X and the amplitude value detection data Y output from the A / D converter 13 is expressed as follows: Y = a _H X ⁿ (10) where a _H is approximated by an n-th exponential function of the coefficient (See FIG. 5). At this time, X = (Y / a _H ) ^{1 / n} , and from the relationship between power and voltage (P = V ² / R), the transmission power T _POWER becomes T _POWER = b _H X ² = b _H ｛(Y / A _H ) ^{1 / n} ｝ ² = b _H (Y / a _H ) ^{2 / n} = c _H Y ^{2 / n} (11) where b _H and c _H are exponential functions of Y in the form of coefficients. It can be approximated (see FIG. 6).

When the transmission frequency f _T is f _L <f _T <f _C , the calculation circuit 14B calculates the transmission power from the equations (7) and (9) using an exponential function interpolated as in the following equation. do. T = {c _L + [(f _T −f _L ) (c _C −c _L ) / (f _C −f _L )]} Y ^{2 / n} (12) Also, when the transmission frequency f _T is f _C In the case of <f _T <f _H , the calculation circuit 14B calculates the transmission power from the equations (9) and (11) using an exponential function interpolated as in the following equation. T = {c _C + [(f _T −f _C ) (c _H −c _C ) / (f _H −f _C )]} Y ^{2 / n} (13)

A good approximation can be obtained by setting n in the equations (6) to (13) to, for example, 1 for linear detection and 2 for square detection, but the value of n is not particularly limited. . FIG.
2 shows an approximation curve when the detection characteristic observed between the input of the detection circuit 11 and the output of the A / D converter 13 is approximated by an n-order function other than the first-order function. If n is fixed,
The adjustment items in the expressions (7), (9), (11), (12), and (13) are only c _L , c _C , and c _H.

At first, (7),
(9), coefficients c _L , c _C , and c _{H in} equations (11) to (13)
Is stored in a rewritable manner, and through the adjustment process, the output power of the power amplifying unit 8 and the calculation circuit 14B separately for the frequencies f _L , f _C , and f _H (7), (9),
Correction is performed so that the error from the calculated transmission power T _POWER according to the equation (11) is minimized. The calculation circuit 14B receives the transmission frequency data from the frequency control unit 5, reads out the coefficient c _L stored in the memory 16B if the transmission frequency f _T = f _L , and calculates the transmission power according to the equation (7). Then, if f _T = f _C , the coefficient c _C stored in the memory 16B is read, and the transmission power is calculated according to the equation (9). If f _T = f _H , the coefficient c _C is stored in the memory 16B. The coefficient c _H is read, and the transmission power is calculated according to the equation (11).

The calculation circuit 14B calculates f_L<F_T<F
_CIf so, the coefficient c stored in the memory 16B_LAnd c_C
And calculate transmission power according to equation (12).
Then f _C<F_T<F_HIs stored in the memory 16B.
Coefficient c_CAnd c_HAnd send it according to equation (13).
Calculate the transmission power. The first adjustment mode of the adjustment panel 17B
Press the mode key to enter the first adjustment mode.
Coefficient c stored in 6B_LCan be changed. First adjustment
In the adjustment panel 17B under the mode, the coefficient c_LIncrease or decrease
Coefficient c using key_LVariable operation, depending on the operation
Parameter changing circuit 18B_LWrite
Replace and update.

When the second adjustment mode key of the adjustment panel 17B is pressed to enter the second adjustment mode, the coefficient c _C stored in the memory 16B can be changed. Adjustment panel 17B under the second adjustment mode, when the variable operation of the coefficient c _C using the increase and decrease keys coefficients c _C, parameter changing circuit 18B is updated by rewriting the b _C of the memory 16B in accordance with the operation. Further, when the third adjustment mode is pressed by pressing the third adjustment mode key of the adjustment panel 17B, the coefficient c _H stored in the memory 16B can be changed. When the variable operation of the coefficient c _H is performed using the increase / decrease key of the coefficient c _{H on} the adjustment panel 17B in the third adjustment mode, the parameter change circuit 18B rewrites and updates c _H in the memory 16B according to the operation. Other components of the transmission power detection / display unit 10B and other components of the transmitter are configured exactly the same as in FIG.

Next, the operation of the above embodiment will be described. It is assumed that n in the equations (7), (9), and (11) to (13) is fixed to a predetermined value determined by the detection method in the detection circuit 11. For example, for linear detection, n
= 1, and n = 2 for square-law detection. It is assumed that appropriate initial values of the coefficients c _L , c _C , and c _{H in} the equations (7), (9), (11) to (13) are stored in the memory 16B in advance.

First, a method of adjusting the coefficients c _L , c _C , and c _H for canceling the variation in the circuit configuration of the detection circuit 11 will be described. A standard signal generator is connected to the transmitter instead of the microphone 1 to input a standard signal having a constant amplitude and a constant frequency. A power meter with a dummy load is connected instead of the transmitting antenna 9. The transmission frequency is set to the lower limit f _L by operating the frequency variable operation unit 4. The standard signal is FM-modulated by the modulator 2 and then converted by the frequency converter 3 into an RF signal of the transmission frequency f _L. After the level of the RF signal is changed by the level changing unit 6, the power is amplified by the power amplifying unit 8. When the first adjustment mode key of the adjustment panel 17B is pressed to set the first adjustment mode, the parameter change circuit 18B can rewrite the coefficient c _L of the memory 16B, and the calculation circuit 14B uses the coefficient c _{L of the} memory 16B. Then, the transmission power is calculated according to (7).

Next, the output variable operation section 7 is operated so that the power meter becomes the reference value T ₀ (> 0) for adjustment. In this state, when the increase / decrease key of the coefficient c _L is pressed on the adjustment panel 17B to perform a variable operation of c _L , the parameter change circuit 18
B updates c _L in the memory 16B according to the operation. The calculation circuit 14B calculates the transmission power according to (7) using the coefficient c _{L of the} memory 16B. When the display of the power indicator 16 indicates T ₀ , the variable operation of b _L is stopped. Thereby, the adjustment of c _L is completed, and the power value of the RF signal output from the power amplifying unit 8 at the time of the frequency f _L and the calculation circuit 14
The error of the output value of B is reduced.

Next, the frequency variable operation section 4 is operated to set the transmission frequency to f _C at the center of the variable range, and the adjustment panel 1
Press the second adjustment mode key of 7B to set the second adjustment mode. Then, the parameter change circuit 18B stores the memory 1
The coefficient c _C of 6B can be rewritten, and the calculation circuit 14B calculates the transmission power according to (9) using the coefficient c _{C of the} memory 16B.

Next, the output variable operation section 7 is operated so that the power meter becomes the reference value T ₀ (> 0) for adjustment. In this state, when the operator presses the increase / decrease key for the coefficient c _{C on} the adjustment panel 17B to perform a variable operation of c _C , the parameter change circuit 18
B updates c _C in the memory 16B according to the operation. The calculation circuit 14B calculates the transmission power according to (9) using the coefficient c _{C of the} memory 16B. When the display of the power indicator 15 indicates T ₀ , the variable operation of c _C is stopped. Thereby, the adjustment of c _C is completed, and the power value of the RF signal output from the power amplifying unit 8 at the time of the frequency f _C and the calculation circuit 14
The error of the output value of B is reduced.

[0046] Finally, the transmission frequency by operating the variable frequency operation unit 4 is set to the upper limit of f _H of the variable range, press third adjustment mode key adjustment panel 17B, is set to the third adjustment mode. Then, the parameter changing circuit 18B can rewrite the coefficient c _{H of the} memory 16B, and the calculation circuit 14B calculates the transmission power according to (11) using the coefficient c _{H of the} memory 16B.

Next, the output variable operation section 7 is operated so that the power meter becomes a reference value T ₀ (> 0) for adjustment. In this state, when the operator presses the increase / decrease key for the coefficient c _{H on} the adjustment panel 17B to perform a variable operation of c _H , the parameter change circuit 18
B updates c _H in the memory 16B according to the operation. The calculation circuit 14B uses the coefficient c _{H of the} memory 16B to obtain (11)
Calculate the transmission power according to When the display on the power indicator 15 indicates T ₀ , the variable operation of c _H is stopped. Thus, the adjustment of c _H is completed, and the power value of the RF signal output from the power amplifying unit 8 at the time of the frequency f _H and the calculation circuit 1
The error of the output value of 4B is reduced.

Thereafter, the adjustment mode release key is pressed on the adjustment panel 17B to release the adjustment mode, and the set is shifted to the normal operation mode. In the normal operation mode, the operation of increasing or decreasing the coefficient on the adjustment panel 17B is ignored by the parameter changing circuit 18B.

Next, the operation in the normal operation mode will be described. With the microphone 1 and the transmission antenna 9 connected, the audio signal input to the microphone is FM-modulated by the modulation unit 2, and then the RF signal of the transmission frequency corresponding to the operation of the frequency variable operation unit 4 by the frequency conversion unit 3. Converted to a signal. Then, after being changed to a level corresponding to the operation of the output variable operation unit 7 by the level variable unit 6, the power is amplified by the power amplification unit 8 and radiated from the transmission antenna 9.

The transmission power varies according to the operation of the output variable operation unit 7, and is detected and displayed by the transmission power detection / display unit 10B. That is, a part of the RF signal output from the power amplification unit 8 is input to the detection circuit 11 and diode-detected, and a detection voltage indicating an amplitude value is output.
The detected voltage is divided by a voltage dividing circuit 12 into a predetermined voltage dividing ratio, then quantized by an A / D converter 13 into 8 bits, and output as amplitude value detection data Y. The detection characteristics viewed between the input amplitude value X of the detection circuit 11 and the amplitude value detection data Y output from the A / D converter 13 include the input amplitude value of the detection circuit 11 when linear detection is performed. Between X and the amplitude value detection data Y output from the A / D converter 13, the equations (7), (9), and (11) are respectively provided for the transmission frequencies f _L , f _C , and f _H. In the case of performing linear detection with n = 1 and performing non-linear detection, between X and Y, for each of the transmission frequencies f _L , f _C , and f _H ,
There is an exponential non-linearity where n ≠ 1 in the equations (7), (9) and (11) (see FIG. 5).

The calculation circuit 14B determines that the transmission frequency f _T indicated by the transmission frequency data input from the frequency control section 5 is f
_{When L} (f _C or f _H ), using the adjusted coefficient c _L (c _C or c _H ) stored in the memory 16B,
(7) The transmission power T from the amplitude value detection data Y is calculated by the exponential function (see FIG. 6) of the equation ((9) or (11)).
_POWER is calculated and output to the power display 15 for digital display.

The transmission frequency input from the frequency control unit 5
Transmission frequency f indicated by wave number data_TIs f_L<F_T<F_C
, The adjusted coefficient c stored in the memory 16B_LWhen
c_C, The amplitude value is detected by the exponential function of equation (12).
From output data Y to transmission power T _POWERCalculate the power table
Output to the indicator 15. In addition, input from the frequency control unit 5
Transmission frequency f indicated by the transmission frequency data_TIs f_C<F
_T<F_HIn the case of, the adjusted member stored in the memory 16B
Number c_CAnd c_HAnd using the exponential function of equation (13),
From the amplitude value detection data Y to the transmission power T _POWERCalculate
Output to the power indicator 15.

According to this embodiment, the detection characteristic of the detection circuit 11 changes depending on the frequency.
The detection circuit 11 performs linear detection by diode detection,
When the detection characteristic seen between the input of the detection circuit 11 and the output of the A / D converter 13 can be approximated by an exponential function, for example, by square detection, the relationship between power and voltage (P = V ² / R) Therefore, the relationship between the output of the A / D converter 13 and the transmission power can be well approximated using an exponential function for each frequency, so that power detection with a small error can be performed regardless of the frequency, and accurate display of the transmission power can be achieved. It becomes possible. Further, since the coefficient of each frequency of the exponential function to the first to third adjustment mode adjustment panel 17B, but is adjustable, adjustment items coefficients c _L,
Since there are only three of c _C and c _{H, the number} of adjustment steps is small, and the work is easy.

When there is no exponential function coefficient data corresponding to the transmission frequency in the memory 16B, the calculation circuit 14B uses the exponential function coefficient data stored corresponding to the upper and lower frequencies of the transmission frequency. Since the transmission power is calculated by using the interpolated exponential function, correction can be performed with little error regardless of how the frequency of the RF signal changes.

In each of the above embodiments, in order to detect and display the transmission power of the transmitter, the RF signal output from the power amplifying unit 8 is detected by the detection circuit 11, and the divided voltage and A / D are detected. The calculation circuit 14A or 14B obtains the transmission power by exponential function approximation for the amplitude value detection data obtained by the conversion. However, when it is desired to detect and display the antenna input power of the receiver, The intermediate frequency signal extracted from the front end is input to the detection circuit 11 of FIG. 1, and the detection output of the detection circuit 11 is A / D converted to obtain amplitude value detection data Y. Then, in the calculation circuit 14A, the antenna input power with respect to the amplitude value detection data Y is converted into an exponential function of the equation (5)
It may be approximated by the calculation so that the error between the antenna input power and the output value of the calculation circuit 14A becomes small) and displayed on the power display 15.

[0056]

According to the present invention, power detection with a small error can be performed by a detection means for performing linear detection or exponential non-linear detection such as diode detection. Further, since the number of adjustment steps of the coefficient parameter of the calculation formula used for the power calculation is small, the adjustment work can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmitter with a transmission power detection / display function according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a graph of an approximate function of a detection characteristic viewed between an input of a detection circuit and an output of an A / D converter in FIG. 1;

FIG. 3 is a diagram illustrating an exponential function graph used by a calculation circuit in FIG. 1 to calculate a transmission power.

FIG. 4 is a block diagram of a transmitter with a transmission power detection / display function according to a second embodiment of the present invention.

5 is a diagram showing a graph of an approximation function of a detection characteristic for each frequency as seen between an input of a detection circuit and an output of an A / D converter in FIG. 4;

FIG. 6 is a diagram showing an exponential function graph used by a calculation circuit in FIG. 4 to calculate transmission power.

FIG. 7 is a block diagram of a conventional transmitter having a transmission power detection / display function.

FIG. 8 is a diagram showing a detection characteristic for each frequency as seen between an input of a detection circuit and an output of an A / D converter in FIG. 7;

9 is a diagram showing a line graph used by a calculation circuit in FIG. 7 for calculating transmission power.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Microphone 2 Modulation part 3 Frequency conversion part 4 Frequency variable operation part 5 Frequency control part 6 Level variable part 7 Output variable operation part 8 Power amplification part 9 Transmission antenna 10A, 10B Transmission power detection / display part 11 Detection circuit 12 Voltage dividing circuit 13 A / D converter 14A, 14B
Calculation circuit 15 Power display 16A, 16B
Memory 17A, 17B Adjustment panel 18A, 18B
Parameter change circuit

Claims (4)

[Claims] 1. A detecting means for detecting a level by detecting an AC signal taken from an arbitrary point of a device or a circuit to be detected, and an exponential function of an output of the detecting means with a power of an arbitrary point of the device or a circuit to be detected. The power detection means to be obtained by approximation and output, and the coefficient of the exponential function used in the power detection means, so that the error between the power of the arbitrary point of the detection target device or the circuit and the output value of the power detection means becomes small. An adjustment means for adjusting, and a power detection device. 2. A detecting means for detecting a level by detecting an AC signal taken from an arbitrary point of a device or a circuit to be detected, and an exponential function of an output of the detecting means by measuring a power of an arbitrary point of the device or a circuit to be detected. In this case, a plurality of exponential functions are prepared for each frequency in accordance with the detection characteristics of the detection means for each frequency, and the power value obtained by approximation with the exponential function corresponding to the frequency of the AC signal is obtained. A power detection device, comprising: power detection means for outputting. 3. The coefficient of each exponential function for each frequency used in the power detection means is adjusted so that the error between the power of the arbitrary target point of the detection target device or circuit and the output value of the power detection means is reduced for each frequency. 3. The power detection device according to claim 2, further comprising an adjusting unit that adjusts the power. 4. The power detection means uses an exponential function interpolated from two exponential functions having frequencies close to the AC signal when the frequency of the AC signal does not match the prepared exponential function.
The power detection device according to claim 3, wherein a power value is obtained.