JP3046912B2 - Linear circuit gain detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear circuit gain detecting device for detecting the gain of a linear circuit to which various burst signals are input.

[0002]

2. Description of the Related Art In a linear circuit such as an amplifier incorporated in various signal processing devices, the gain changes in accordance with a change in ambient temperature and a change in input signal frequency. As a result, even if the input signal level is constant, the output signal level fluctuates greatly.

Therefore, in a test apparatus in which the output signal level fluctuation is not negligible, as shown in FIG. 7, in a linear circuit in which the amplifier 1 is incorporated, a variable gain circuit is provided before the amplifier 1 for amplifying the input signal a. 2, the automatic gain controller 3 controls the variable gain circuit 2 to control the signal level of the output signal b output from the amplifier 1 to outside the linear circuit to a constant value.

That is, after the output signal b input to the automatic level control device 3 is detected by the detector 3a, the noise component is removed by the low-pass filter 3b,
c. The differential amplifier 3c is a low-pass filter 3
by detecting the b output voltage V _S with a preset voltage difference between the reference voltage Vr (V _S -Vr), and sends a gain control signal corresponding to the difference voltage to the variable gain circuit 2.

[0005]

However, in the method of controlling the gain of the linear circuit shown in FIG. 7 to a constant value, the average value of the amplitude is almost constant such as an unmodulated signal, an AM signal, and an FM signal. When the signal is a continuous signal, the output signal level can be controlled to a constant value.

However, in the case where the input signal a is a burst signal a ₁ , a ₂ , a ₃ which is turned on only for a certain period T _S within a certain period T ₀ as shown in FIG.
The signal level of the output signal b becomes a signal level averaged over the entire period of one cycle T ₀ , and the signal ON time T
The correct output signal level in _S cannot be obtained.

The duty ratio [T _S / T ₀ ] represented by the ratio of the period T ₀ of the input signal a, which is the burst signals a ₁ , a ₂ and a ₃ , to the signal on time T _S is constant. If
By multiplying the gain control signal for the variable gain circuit 2 by a constant corresponding to the duty ratio [T _S / T ₀ ], the output signal level can be controlled to a predetermined value.

However, as shown in FIG. 8, when the period T _{0 of the} input signal and the signal on time T _S are different from each other, it is impossible to always obtain a correct signal level in the signal on time T _S of the output signal b. Very difficult.

The input signal a is a burst signal a ₁ , a
₂ , a ₃ and quadrature phase modulated,
Ni will as shown in the lower position of FIG. 8, in the signal on-time of the burst signal a ₃ T _S, in accordance with the data value of the digital data to be transmitted, amplitude changes. The cycle of the change of the amplitude changes according to the digital data transmission speed of the burst signals a ₁ , a ₂ and a ₃ .

Therefore, even if the signal level for a fixed time within the signal on-time T _S in the burst signal is simply averaged by the detector 3a and the low-pass filter 3b, the data included in the fixed time is not included. Since the number changes, all burst signals a ₁ , a ₂ , a
_The correct signal level cannot be detected over ₃ .

The present invention has been made in view of such circumstances, and detects an integrated value of an output signal when the integrated value of the input signal reaches a reference value. It is an object of the present invention to provide a linear circuit gain detection device that can always accurately detect the gain of a linear circuit even if a plurality of types of burst signals have different ON times.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an input signal in a linear circuit to which a plurality of types of input signals composed of burst signals having different periods and different signal ON times are inputted, and the linear circuit. In a linear circuit gain detection device for detecting the gain of a linear circuit from each signal level with an output signal output from an output signal, an input signal is integrated to output a first integrated value, and a burst within a predetermined measurement time is output. A first integrator having an integration constant whose integral value reaches a reference value corresponding to the ON state of the burst signal even for an input signal having the shortest total on-time of the signal, and a first integral value reaching the reference value Then, a comparator that outputs a measurement trigger signal, a second integrator that has the same integration constant as the first integrator, integrates the output signal, and outputs a second integrated value, and a measurement trigger. Each time a signal is output, a gain calculator that calculates and outputs the gain of the linear circuit using the second integral value and the reference value, and outputs first and second gains each time a gain is output from the gain calculator. And an arithmetic processing unit for sending a reset signal to the integrator and averaging each gain output within the measurement time.

[0013]

In the linear circuit gain detection device thus constructed, an input signal composed of, for example, a burst signal is input to the linear circuit and the first integrator. The output signal of the linear circuit is input to a second integrator. The first and second integrators have the same integration constant. Then, when the integrated value of the first integrator reaches a reference value corresponding to the ON state of the burst signal, a measurement trigger signal is output from the comparator.

At this timing, the gain of the linear circuit is calculated based on the integrated value of the second integrator indicating the signal level of the output signal and the reference value which is the signal level of the input signal.

Therefore, even if the input signal is a burst signal whose signal on-time is discontinuous, a signal value corresponding to the signal on-time is obtained by the above-mentioned integration processing, and the correct gain of the linear circuit is calculated.

Further, the integration constants of the first and second integrators are set such that the integrated value becomes a reference value within a total on-time within a preset measurement time of various burst signals inputted to the linear circuit. Set to reach. That is, even if the input signal has the minimum total on-time, one or more gains are calculated within the measurement time.

Therefore, a small number of gains can be obtained within one measurement time for an input signal having a short total on-time, and a large number of gains can be obtained within one measurement time for an input signal having a long total on-time. Gain is obtained. Then, the respective gains obtained within the measurement time are averaged to obtain the final gain.

In general, when transmitting the same amount of data, the data transmission speed of an input signal having a short total on-time within the measurement time is high, and the data transmission speed of an input signal having a long total on-time is high. Low. Therefore,
Even if the input signal has a short total on-time and an input signal with a small number of gains obtained during the measurement time, an amplitude component consisting of a large number of data is included during the signal-on period, so that a large number of gains are required. There is no particular decrease as compared to the gain measurement accuracy for an input signal having a long averaging total on-time.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a linear circuit gain detection device according to an embodiment.

A pair of modulation signals I and Q as input signals
Has a period T ₀ , as shown in the time chart of FIG. 3, and a predetermined time (signal-on time T _S ) within the period T ₀ .
Only a signal or a burst signal to be output.

The pair of modulation signals I and Q as the input signals are input to the quadrature modulator 5 in the linear circuit 4. As shown in FIG. 2, when the amplitude of each pair of modulated signals I and Q is I and Q, the quadrature modulator 5 has a P point of coordinates (I, Q) on the rectangular coordinates. Is converted into a quadrature modulated signal c having a predetermined carrier frequency f _C having an amplitude proportional to a distance (I ² + Q ² ) ^1/2 from the origin.

The quadrature modulated signal c output from the quadrature modulator 5 is converted to a desired frequency by the frequency converter 6 and then input to the variable gain circuit 7. The variable gain circuit 7 adjusts the amplitude of the frequency-modulated quadrature modulation signal c ₁ based on the gain control signal d input from the outside, and sends it to the next amplifier 8. The amplifier 8 amplifies the quadrature modulated signal c ₂ , the amplitude of which has been adjusted by the variable gain circuit 7, at a predetermined amplification factor, and outputs the output signal b ₁ from the linear circuit 4.

The pair of modulated signals I and Q as input signals are input to an input level calculator 9. The input level calculator 9 calculates and outputs the sum (I ² + Q ² ) of the squares of the two modulated signals I and Q as a value corresponding to the amplitude of the input signal input to the linear circuit 4. The output signal e of the input level calculator 9 is input to the first integrator 11 via the switch 10.

The first integrated value A obtained by the first integrator 11 is input to the comparator 12 and also to the gain calculator 13. The reference value Vr substantially corresponding to the signal level of the output signal e corresponding to the input signal at the signal ON time T _S is input to the comparator 12. When the first integrated value A reaches the reference value Vr, the comparator 12 sends the measurement timing signal g to the gain calculator 13 and
The open / close control signal h sent to the switches 10 and 14 is set to a high level to open the switches 10 and 14. Therefore, the switches 10 and 14 are closed when the first integrated value A is less than the reference value Vr.

The output signal b ₁ of the linear circuit 4 is supplied to the detection circuit 15
Is detected by the envelope. The detection signal E of the detection circuit 15 is squared (E ² ) by the next output level calculator 16. The output signal i of the output level calculator 16 is input to the second integrator 17 via the switch 14. Second integrator 17
The second integral value B obtained in step (1) is input to the gain calculator 13.

The gain calculating section 13 includes a gain calculating section 13a and A
/ D converter 13b. Gain calculator 13
a calculates the logarithmic ratio G between the first integral value A and the second integral value B according to the following equation.

G = 10 · log (B / A) The calculated logarithmic ratio G is input to the next input terminal of the A / D converter 13b. When the measurement timing signal g is input from the comparator 12, the A / D converter 13 b A / D converts the logarithmic ratio G applied to the input terminal at this time, and obtains the gain D of the linear circuit 4 as the gain D. It is sent to the next arithmetic processing unit 18.

When the measurement timing signal g is output, the first integral value A is equal to the reference value Vr as shown in FIG. D = 10 · log (B / Vr) The integration constant C of the first integrator 11 is, as shown in FIG. A predetermined measurement time T ^M in the input signal a consisting of Q
, The total on-time of the signal on-time T _S (T _S + T
_S + ...) is set to a value such that the first integrated value A to be output reaches the reference value Vr even if the input signal a has the minimum time.

Therefore, regardless of the input signal a having any period T ₀ and signal ON time T _S , one or more gains D are always output from the gain calculator 13 during the measurement time T _M.

Next, the configuration and operation of the arithmetic processing unit 18 to which the gain D is input from the gain calculating unit 13 will be described. The arithmetic processing unit 18 is constituted by a kind of microcomputer. Further, it has therein a data memory 18a for storing each gain D sequentially detected, a gain averaging unit 18b and a reset signal generation score 18c configured on an application program. A timer (not shown) is provided in the arithmetic processing unit 18.

In the data memory 18a, there are formed a plurality of areas for sequentially storing the gains D sequentially inputted from the gain calculator 13. Then, for example, when a measurement start command is input by the operation of the operator, the calculation processing of the average gain Dm for the linear circuit 4 is executed according to the flowchart shown in FIG.

When the flow chart of FIG. 4 is started, an index n for designating an area number of the data memory 18a is initialized to 0 in P (program step) 1.
When the above initial processing is completed, a timer is started at T2 (T = 0).

At P3, when it is confirmed that the timer time T has not reached the above-described measurement time T _M , at P4,
The reset signal generator 18c is activated to send a reset signal j to the first and second integrators 11 and 17.

Each integrator 1 to which the reset signal j has been input
1, 17 are their own integrated values A. Clear B to 0. As a result, the first integrated value A falls below the reference value Vr, so that the open / close control signal h sent from the comparator 12 to each of the switches 10 and 14 becomes low level, and each of the switches 10 and 14 It becomes a closed state. Therefore, each integrator 1
1, 7 are output signals e. Start the integration operation for i.

In P5 and P9, before the timer time T reaches the measurement time T _M , the first integral value A is set to the reference value V.
When r has been reached, the measurement trigger signal g is output from the comparator 12, so that one gain D output from the gain calculator 13 is read (P6). In this state,
The comparator 12 outputs a high-level open / close control signal h. As a result, the switches 10 and 14 shift to the open state, so that the integrated values A and B maintain constant values.

At P7, the read gain D is stored in the n-th area of the data memory 18a (Dn = D). When the storage processing for one gain D in the data memory 18a is completed, the index n is increased by 1 (P
8) Returning to P3, the timer time T is again measured time T
Check if _M has passed. If not, a clear signal is sent to each of the integrating circuits 11 and 17.

When the time T of the timer reaches the measurement time T _M at P3 or P9, the process of collecting the gain D is completed, and the process proceeds to P10, where the gain averaging unit 18b is started to activate the data memory 18a. Of the n gains D0. The average gain Dm of D1,..., Dn-1 is calculated.

When the process of calculating the average gain Dm is completed, a predetermined reference gain Dr and the average gain Dm calculated this time are calculated.
Is transmitted to the variable gain circuit 7 of the linear circuit 4 as a gain control signal d.

Therefore, the correct average gain Dm of the linear circuit 4
Is detected, and the gain of the linear circuit 4 is set to a predetermined reference gain Dr based on the detected average gain Dm.
Is automatically controlled.

In the linear circuit gain detection device thus configured, as shown in the time chart of FIG.
For example, a pair of modulation signals I and Q as an input signal composed of a burst signal having a period T ₀ and a signal on time T _S are input to the linear circuit 4 and the first integrator via the input level calculator 9. 11 is input.

The output signal b ₁ of the linear circuit 4 is input to the second integrator 17 via the detector 15 and the output level calculator 18. Since the first and second integrators 11 and 17 have the same integration constant C, the first and second integration values A and B are monotonic according to the integration constant C within the signal ON time T _S. To increase.

When the integrated value A of the first integrator 11 reaches the reference value Vr corresponding to the ON state of the burst signal, the comparator 12 outputs the measurement trigger signal h. At this timing, one gain D of the linear circuit 4 is adjusted based on the integrated value B of the second integrator 17 indicating the signal level of the output signal b ₁ and the reference value Vr which is the signal level of the input signal. Is calculated.

The integration constant C of each of the integrators 11 and 17 is
Also the total ON time in the measurement time within T _M which is previously set in various burst signal to be input to the linear circuit _{4 (T S + T S +} ...) is an input signal a having the lowest time, The first integrated value A output is the reference value Vr
Is set to a value that reaches

Therefore, the input signal a composed of a burst signal having any period T ₀ and signal ON time T _S
The gain D is always output from the gain calculator 13 during the measurement time T _M even for the pair of modulation signals I and Q. Therefore, a correct gain D corresponding to the signal ON time T _S state can always be obtained.

Further, as long as the signal ON time T _S continues within the measurement time T _M , a plurality of gains D are repeatedly collected according to the integration constant C described above, and the collected gains D are obtained.
Is obtained.

For example, as shown in FIG. 5, if the signal ON time T _S within the period T ₀ is long, the duty ratio [T _S / T
_0] If the large input signals a _5, one measurement time T
Within _M , a repeated measurement trigger signal g is output, and a number of gains D1, D2,..., D10 are obtained.

Therefore, the average gain Dm is obtained by averaging these ten gains D, so that the accuracy of measuring the gain D of the linear circuit 4 is greatly improved. As described above, the data rate of the input signal a ₄ total ON time in the measuring time T _M is shown shorter for example in FIG. 6 is high, the transmission of the data input signal a ₄ total on time is shown in the long 5 Speed is low.

Therefore, even if the input signal a is a quadrature-modulated burst signal, the input signal is an input signal with a short on-time of the synthesizer, and the gain D obtained within the measurement time T _M is obtained.
Even though the input signal a ₅ number is small, because it contains the amplitude component composed of a number of data in the signal ON period,
It never decreases particularly the total ON time for averaging a number of gain D as compared to the measurement accuracy of the gain D of the long input signal a _4.

The present invention is not limited to the embodiment described above. In the device of the embodiment shown in FIG. 1, a linear circuit 4 to which a pair of burst-like modulated signals I and Q is input is used as a linear circuit. However, it may be a linear circuit composed of only a frequency converter or a linear circuit composed of only an amplifier. Further, the input signal may be only one orthogonally modulated signal after the orthogonal transformation, and is not necessarily limited to the orthogonally modulated signal.

[0050]

As described above, in the gain detection apparatus for a linear circuit according to the present invention, when the integrated value of the input signal to the linear circuit reaches the reference value corresponding to the signal ON state, the output signal from the linear circuit is output. , And the gain is calculated. Further, the integration constant of each integrator is set to a value such that the integrated value always reaches the reference value within the total signal on time within the measurement time, and for an input signal having a long total signal on time, , A repetitive gain is obtained.

Therefore, even if the input signal is a plurality of types of burst signals having different periods and different signal ON times, the gain in the signal ON time in the linear circuit can always be detected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a linear circuit gain detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing output characteristics of a quadrature modulator in a linear circuit in the device of the embodiment.

FIG. 3 is a time chart showing the operation of the apparatus of the embodiment.

FIG. 4 is a flowchart showing the operation of an arithmetic processing unit in the apparatus of the embodiment.

FIG. 5 is a time chart showing the operation of each unit when an input signal having a long total signal on time is input to the linear circuit of the device of the embodiment;

FIG. 6 is a time chart showing the operation of each unit when an input signal having a short total signal on-time is input to the linear circuit of the device of the embodiment;

FIG. 7 is a block diagram showing a schematic configuration of a general automatic level control device;

FIG. 8 is a signal waveform diagram showing a plurality of types of burst signals having different periods and signal ON times.

[Explanation of symbols]

4 linear circuit, 5 orthogonal transformer, 6 frequency converter, 7
... variable gain circuit, 8 ... amplifier, 9 ... input level calculator,
Reference numerals 10, 14: switch, 11: first integrator, 12: comparator, 13: gain calculator, 13a: gain calculator, 13b
... A / D converter, 15 ... Detector, 16 ... Output level calculator, 17 ... Second integrator, 18 ... Calculation processing unit, 18s ...
Data memory, 18b: gain averaging unit, 18c: reset signal generation unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-30349 (JP, A) JP-A-5-347521 (JP, A) JP-A-5-129861 (JP, A) JP-A-5-129 7178 (JP, A) JP-A-4-239808 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 27/28 H03G 3/30 H03G 3/20

Claims (1)

(57) [Claims] 1. Period (T ₀ ) and signal on time (T _S )
Are linear signals for detecting the gain of the linear circuit from the signal levels of the input signal and the output signal output from the linear circuit in a linear circuit (4) to which a plurality of types of input signals composed of different burst signals are input. in the gain detector circuit, the input to output the first integration value by integrating the input signal (a), the total on-time of the burst signal in a predetermined measuring time (T _M) having the shortest time A first integrator (11) having an integration constant at which the integrated value reaches a reference value (Vr) corresponding to the ON state of the burst signal, when the first integrated value reaches the reference value; A comparator that outputs a measurement trigger signal; and a second integrator that has the same integration constant as the first integrator, integrates the output signal, and outputs a second integrated value (B).
(17) a gain calculator (13) that calculates and outputs a gain (D) of the linear circuit with the second integrated value and the reference value each time the measurement trigger signal is output; Each time a gain is output from the gain calculation unit, a reset signal is sent to the first and second integrators, and an arithmetic processing unit (18) that averages each gain output within the measurement time is included. Detector for linear circuit gain.