JPS6237346B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic adjustment system for electronic circuits, and more particularly to an automatic adjustment system for linear semiconductor integrated circuits.

In other words, in semiconductor integrated circuits, various element constants of various circuit elements such as active elements such as transistors and passive elements such as diodes and resistors within the semiconductor integrated circuit exhibit variations due to variations in manufacturing conditions. Generally speaking, the various DC or AC characteristics of integrated circuits exhibit variations.

Therefore, in order to inspect whether a manufactured integrated circuit is good or bad, it is necessary to measure whether the various DC or AC characteristics of the integrated circuit are within respective standard ranges.

On the other hand, in some types of integrated circuits, some of the characteristics of the integrated circuit depend on element constants such as the impedance of external circuit elements externally connected to the lead terminals of the integrated circuit. In order to perform measurement work, some of the above characteristics are set to the optimum state by adjusting the element constants such as the impedance of the external circuit element externally connected to the above lead terminal, and then other characteristics are adjusted. measurement work must be carried out.

Further, in some types of integrated circuits, the first and second characteristics of the integrated circuit are mutually related to the respective impedances of first and second external circuit elements externally connected to the lead terminals of the integrated circuit. Therefore, in order to perform the characteristic measurement work of the integrated circuit, the second characteristic is set to the optimum state by adjusting the impedance of the second external circuit element, and then the second characteristic is set to the optimum state. By adjusting the impedance of external circuit element 1,
When the first characteristic is set to the optimum state, the change in impedance of the first external circuit element affects the second characteristic, resulting in a complicated development in which the second characteristic deviates from the optimum state. may occur.

Therefore, in order for the adjuster to set and adjust the first and second characteristics to the optimum conditions, it is necessary to
There is a problem in that it is necessary to alternately repeat the adjustment of the impedance of the and the second external circuit element, and a long adjustment time is required.

The present invention has been made to solve the above problem, and its purpose is to adjust the first characteristic parameter of an electronic circuit in response to impedance changes of the first variable impedance means and the second variable impedance. The respective values of the first characteristic parameter and the second characteristic parameter of the electronic circuit, where the respective values of the first characteristic parameter and the second characteristic parameter change while being influenced by each other, are substantially deviated from their respective desired values. The present invention aims to provide an automatic adjustment method for an electronic circuit that can be set to the minimum state in a short period of time.

The basic structure of the present invention to achieve this object is characterized by having each of the constituent elements as described in the claims section, and each embodiment of the present invention will be described below. will be explained in detail with reference to the drawings.

1 Embodiment 1: FIG. 1 is a block diagram showing the main parts of an automatic adjustment system in which the automatic adjustment method of the first embodiment of the present invention is used. This is a linear semiconductor integrated circuit for FM IF systems that has functions such as wave detection and center meter drive, and the numbers in circles indicate the lead terminal numbers of the integrated circuit.

The input coupling capacitor is connected to the 1st lead terminal.
A signal source SG is connected via _C1 and an FM IF signal is applied. Applied to this No. 1 lead terminal
The FM IF signal is limiter amplified by an intermediate frequency amplifier within the integrated circuit, and a signal from which the AM component in the FM IF signal has been removed is taken out from the No. 8 lead terminal. Furthermore, the No. 8, No. 9, and No. 10 lead terminals are equipped with quadrature channels, which will be detailed later.
A phase shift circuit (double-tuned detection coil) composed of coils L ₀ , L ₁ , L ₂ , variable capacitance diodes D ₁ , D ₂ , and capacitors C ₃ , C ₄ , C ₅ for FM detection is connected, A right-angled quadrature signal having a phase difference of 90 degrees from the FM IF signal at the No. 8 lead terminal is obtained at the No. 9 lead terminal. In addition, this integrated circuit has a gate circuit for quadrature FM detection in the form of a differential switching circuit, and this gate circuit has an FM IF reference signal with a phase angle of 0 degrees at the No. 8 lead terminal and an FM IF reference signal at the No. 9 lead terminal. A quadrature quadrature signal with a phase angle of 90 degrees is applied. Therefore, this gate circuit separates the FM quadrature signal whose phase is shifted by the phase shift circuit and the original signal.
A product is created with the FM reference signal, an FM demodulated signal is obtained from the beat component, and this demodulated signal is sent to the No. 6 lead terminal. The quadrature that takes
The circuit operation of the FM detection circuit is as per IEEE
TRANSACTION ON BROADCAST AND
TELEVISION RECEIVERS NOVEMBER1967
VOLUME BTR-13 NUMBER 3 Please refer to pages 60 to 65 for detailed explanation. Furthermore, a center meter CM is connected between the No. 10 lead terminal and the No. 7 lead terminal, and the No. 7 lead terminal is connected to the center meter CM.
A center meter drive signal is generated based on the No. 10 lead terminal. As shown in Figure 3, when the FM receiver is correctly tuned to the center frequency of ₀ , the pointer of this center meter shows the zero point, and when the FM receiver is out of tune from the center frequency, the pointer shows the zero point. It must be adjusted to indicate a positive (+) or negative (-) value. The zero point adjustment of this center meter can be performed by adjusting the impedance of any of the primary impedance elements L ₁ , D ₁ , and C ₃ of the phase shift circuit connected to the 9th and 10th lead terminals. . Also, as shown in Figure 4, the harmonic distortion factor THD of the FM demodulated signal at the No. 6 lead terminal is determined by the change in the capacitance CD ₂ of the impedance element on the secondary side of the phase shift circuit, such as the variable capacitance diode D ₂ . According to
It varies along the characteristic curve L ₁ . In addition, since the impedance on the primary side and the impedance on the secondary side of this phase shift circuit are coupled by magnetic coupling M, the primary side of the phase shift circuit is connected to each impedance on the secondary side in response to a change in impedance on the secondary side. center meter
The CM guideline and the harmonic distortion factor THD of the FM demodulated signal change while being influenced by each other.

The automatic adjustment method according to the first embodiment of the present invention, which consists of each step described in detail later, includes zero point adjustment of the pointer of the center meter CM, and distortion rate adjustment to minimize the harmonic distortion rate THD. The aim is to complete the process in a short period of time.

First, the pointer of the center meter is measured in the form of a voltage drop caused by the center meter drive signal current flowing between the 7th lead terminal and the 10th lead terminal and the internal resistance of the center meter itself. The voltage drop across this center meter is determined by the impedance converter 1 such as an emitter follower.
4 and 15 to the feedback control circuit 13. This feedback control circuit 13 amplifies the center meter voltage drop applied via resistors R ₃ and R ₄ using a differential amplifier 13b. Furthermore, the resistors R ₁ and R ₂ and the operational amplifier 13a are
Detects the DC voltage level of lead terminal No. 10.
An analog adder circuit consisting of resistors R ₇ , R ₈ , R ₉ and an operational amplifier 13c generates an error amplification voltage of the differential amplifier 13b based on the DC voltage level of the No. 10 lead terminal, and outputs the error amplified voltage through the switch S ₁ . This error amplified voltage is applied to the variable capacitance diode on the primary side of the phase shift circuit.
Applied to D ₁ . Therefore, the error amplified voltage always defines the capacitance value of the variable capacitance diode _D1 so that the voltage drop across the center meter, which is proportional to the deviation of the pointer of the center meter from the zero point, becomes zero. On the other hand, the FM demodulated signal at the No. 6 lead terminal is applied to the harmonic distortion measurement circuit ₁₂ via the output coupling capacitor C2. The AC amplitude value of the fundamental wave component of this FM demodulated signal is
-Detected by the DC converter 12a, on the other hand, the fundamental wave component is removed by the band rejection filter 12b, only the harmonic component is amplified by the amplifier 12c, and the AC amplitude value of this amplified harmonic component is detected by a peak detector, etc. is detected by the AC-DC converter 12d. Further, the analog division circuit 12e divides the AC amplitude value of the detected harmonic component by the AC amplitude value of the detected fundamental wave component, and measures the harmonic distortion value. When switch S ₂ is ON to the 1 side, the analog-to-digital converter 6 connects to the harmonic distortion measurement circuit 1.
The analog value corresponding to the harmonic distortion factor value measured by 2 is converted into a digital signal and supplied to the digital signal comparison circuits 7 and 19, and further to the switch 8b.
This digital signal is supplied to the harmonic distortion factor storage circuit via the harmonic distortion factor storage circuit. When the output digital signal of the analog-to-digital converter 6 is smaller than the digital signal stored in the harmonic distortion factor storage circuit 10, the digital signal comparison circuit 7 controls the switch 8b to
Turn on the analog-to-digital converter 6 above.
The output digital signal is newly stored in the harmonic distortion rate storage circuit 10. Further, when the output digital signal of the analog-to-digital converter 6 is substantially equal to the digital signal stored in the harmonic distortion factor storage device 10, the digital signal comparison circuit 7
Control switch 8a to turn it on,
A first control signal generated by a stepped wave function generation control circuit 2, which will be described later, is stored in a control signal storage circuit 9. The maximum harmonic distortion storage circuit 20 stores a digital signal corresponding to the maximum value THDmax of harmonic distortion allowed by the standard. Therefore, the output digital signal of the analog-digital converter 6 corresponding to the harmonic distortion rate in the lowest harmonic distortion rate state set by the automatic adjustment method of the present invention and the maximum harmonic distortion rate allowed by the above standard. The magnitude relationship with the digital signal corresponding to the value THDmax is determined by the digital signal comparison circuit 19, and the harmonic distortion rate in the state of the lowest harmonic distortion rate is smaller than the maximum value THDmax of the harmonic distortion rate allowed by the upper standard. At times, the output signal of this digital signal comparison circuit 19 controls the program control device 11, and the work shifts to measuring the values of other characteristic parameters of the integrated circuit, such as the S/N ratio and AM rejection ratio, and vice versa. If it is large, the measurement operation is stopped at this stage, and a display device (not shown) displays the measurement result that the harmonic distortion rate of the integrated circuit is defective. On the other hand, analog-digital converter 6
When the switch S ₂ is ON at the 2 side, converts the error amplified voltage generated by the analog adder circuit 13c in the feedback control circuit 13 into a corresponding digital signal, and supplies this digital signal to the storage circuit 16. The digital signal stored in this memory circuit 16 controls the variable voltage generation circuit 17 for generating a DC second control voltage to control the capacitance value of the variable capacitance diode _D1 , and defines the magnitude of this second control voltage. do. Further, the staircase wave function generation control circuit 2 is
It is composed of an initial value storage circuit 2a, a step value storage circuit 2b, a subtraction circuit 2d, and a storage circuit 2c, each of which is capable of processing digital signals, and supplies a first control signal to the storage circuit 3 and the control signal storage circuit 9. Further, the digital signal stored in the initial value storage circuit 2a defines the voltage value of the applied voltage _V21 applied to the variable capacitance diode _D2 in [stage 1], which will be described later, and is stored in the step value storage circuit 2b. The digital signal is the difference voltage V _{21 −V 22} between the applied voltages V 22 and V ₂₁ applied to the variable capacitance diode D ₂ in [Stage 2] and [Stage 1], which will be described later, respectively, and the difference voltage in the subsequent stages. stipulate. Variable voltage generation circuit 4
generates a step wave function voltage V ₂ as shown in FIG. 4 under the control of the first control signal stored in the memory circuit 3, and successively defines the capacitance value CD ₂ of the variable capacitance diode D ₂ . The program control device also controls the timing of the staircase wave function generation control circuit 2.

Further, the automatic adjustment method according to the first embodiment of the present invention consists of the following steps.

[Step 1] First, the program control device 11 controls the step wave function generation control circuit 2 to apply a voltage V to the variable capacitance diode D ₂ as shown in FIG. Supply ₂₁ . Then, due to the magnetic coupling M of the double-tuned detection coil, the alternating current impedance seen from the primary side of this coil changes, and the pointer of the center meter CM deviates from the zero point. This deviation is detected by the feedback control circuit 13, and an applied voltage _V1 that minimizes this deviation is applied to the variable capacitance diode _D1 , and the capacitance value of the variable capacitance diode _D1 is defined. . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally defined, and the distortion factor of the linear integrated circuit 1 under test corresponding to state 1 on the characteristic curve _L1 in FIG. 4 is defined. Ru.
The distortion rate in this state is measured by the harmonic distortion rate measuring circuit 12, converted into a digital signal by the analog-to-digital converter 6, and then converted to a digital signal by the program control device 1.
The signal is applied to the harmonic distortion rate storage circuit 10 through the switch 8b which is turned on by the switch 8b, and is stored in the storage circuit 10.

[Step 2] Next, the program control device 11 similarly controls the step wave function generation control circuit 2 to apply the applied voltage V ₂₁ to the variable capacitance diode D ₂ in the previous [Step 1].
Supplying a smaller applied voltage V ₂₂ . Then, the capacitance value CD ₂ of this variable capacitance diode D ₂ increases,
Therefore, due to the magnetic coupling M of the double-tuned detection coil, the alternating current impedance seen from the primary side of this coil changes, causing the pointer of the center meter CM to deviate from the zero point. This deviation is detected by the feedback control circuit 13, and an applied voltage _V1 that minimizes this deviation is applied to the variable capacitance diode _D1 , and the capacitance value of the variable capacitance diode _D1 is defined. . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally specified, and the distortion factor of the linear integrated circuit 1 under test corresponding to state 2 on the characteristic curve _L1 in FIG. 4 is specified. Ru. The distortion rate in this state is the harmonic distortion rate measurement circuit 12.
is measured, converted into a digital signal by the analog-to-digital converter 6, applied to the digital signal comparison circuit 7, and compared with the distortion factor stored in the harmonic distortion factor storage circuit 10 in [Step 1].

Therefore, the strain rate measured in this [stage 2] is
Since it is smaller than the distortion rate measured in [Stage 1],
Since the output of the digital signal comparison circuit 7 controls the switch 8b and turns it ON, the harmonic distortion rate storage circuit 10 stores the analog-to-digital converter 6 corresponding to the distortion rate in this [stage 2] state. Store digital output signal.

[Stage 3]...Same as [Stage 2] [Stage 4]... [Stage 4']... [Stage 5] Similarly, the program control device 11 controls the staircase wave function generation control circuit 2 to An applied voltage V ₂₅ smaller than the applied voltage V ₂₄ ′ in the previous [stage 4] is supplied to the capacitive diode D ₂ . Then, the capacitance value CD ₂ of this variable capacitance diode D ₂ increases, and therefore, due to the magnetic coupling M of the double-tuned detection coil,
The alternating current impedance seen from the primary side of this coil changes, causing the pointer of the center meter CM to deviate from the zero point. This deviation is detected by the feedback control circuit 13, and the applied voltage V ₁ that minimizes this deviation is applied to the variable capacitance diode D _{1 .}
is applied to define the capacitance value of this variable capacitance diode _D1 . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally defined, and the distortion factor of the linear integrated circuit 1 to be tested corresponding to state 5 on the characteristic curve _L1 in FIG. 4 is defined. Ru. The distortion factor in this state is measured by the harmonic distortion factor measuring circuit 12, converted into a digital signal by the analog-to-digital converter 6, and applied to the digital signal comparison circuit 7. It is compared with the distortion factor stored in the storage circuit 10.

Therefore, the strain rate measured in this [step 5] is:
Since it is substantially equal to the distortion factor measured in [step 4'], the output of the digital signal comparison circuit 7 is output to the switch 8.
Turn on a and 8c and turn off switch 8d. In addition, since the control signal storage circuit 9 stores only the first control signal in [Stage 5] generated from the staircase wave function generation control circuit 2, the switch 8a is controlled to immediately turn off thereafter. Ru.

Therefore, in this state, the center meter
An applied voltage V ₁ that minimizes the deviation of the CM pointer from the zero point is applied to the variable capacitance diode D ₁ ,
An applied voltage _V25 such that the harmonic distortion factor THD is substantially minimized is applied to the variable capacitance diode _D2 , and this state is maintained.

In this holding state, the digital signal comparison circuit 19 calculates the maximum harmonic distortion rate allowed by the standard, which is stored in the harmonic maximum distortion rate storage circuit 20.
By comparing the digital signal corresponding to THDmax with the digital output signal of the analog-to-digital converter 6 corresponding to the distortion factor of the linear integrated circuit 1 to be tested in the holding state, the distortion factor of the linear integrated circuit 1 to be tested is determined. Determine whether the characteristics are good or bad.

After this determination, the distortion factor of this linear integrated circuit 1 to be tested is determined to be the maximum harmonic distortion factor TH allowed by the standard.
When it is smaller than Dmax, this linear integrated circuit 1 to be inspected is determined to be a good product, and switches S ₁ and S ₂
and switch from side 1 to side 2, respectively.

Then, the analog-to-digital converter 6 converts the applied voltage previously applied to the variable capacitance diode _D1 .
V ₁ is converted into a digital signal, and the storage circuit 16 stores this digital signal. This storage circuit 16 is controlled by the program control device 11 so that its stored contents do not change even if the output digital signal of the analog-to-digital converter 6 changes thereafter.
Further, the variable voltage generation circuit 17 is connected to the memory circuit 1.
Generates a DC voltage having the same voltage value as the previously applied voltage V ₁ in response to the digital signal stored in 6, and changes the capacitance value of the variable capacitance diode D ₁ from the zero point of the pointer of the center meter CM. is maintained at a minimum. In this way, even if the input signal conditions of the linear integrated circuit 1 to be inspected change, the applied voltages V ₁ and V ₂₅ in the holding state do not change and are kept constant.

Next, the applied voltage under the condition that this holding state is maintained is
With V ₁ and V ₂₅ applied to the variable capacitance diodes D ₁ and D ₂ , the characteristics of the linear integrated circuit 1 to be tested, such as the S/N ratio and AM rejection ratio, are measured, and the linear integrated circuit to be tested with respect to these characteristics is Good quality of integrated circuit 1. Determine defects.

In the unlikely event that the storage circuit 16 and the control signal storage circuit 9 do not hold the applied voltages V ₁ and V ₂₅ ,
When measuring various characteristics of the linear integrated circuit 1 to be tested, such as S/N ratio and AM rejection ratio, the variable capacitance is The applied voltages V ₁ and V ₂₅ applied to the diodes D ₁ and D ₂ change, causing the pointer of the center meter CM to deviate from the zero point and deviate from the minimum harmonic distortion rate condition.

Therefore, the function of holding the applied voltages V ₁ and V ₂₅ by the memory circuit 16 and the control signal memory circuit 9 is extremely important in testing the characteristics of electronic circuits using the automatic adjustment method of the present invention.

As explained above, according to the first embodiment of the present invention, the initial objective can be achieved for the following reasons.

That is, in response to a change in the capacitance value of the variable capacitance diode _D1 and a change in the capacitance value of the variable capacitance diode _D2 , the pointer of the center meter CM of the linear semiconductor integrated circuit 1 for the FM IF system and the harmonic distortion factor change relative to each other. According to an embodiment of the present invention, when adjusting the zero point of the center meter CM of the integrated circuit and adjusting the distortion rate to minimize the harmonic distortion rate, which changes while being influenced by the In this case, feedback control circuit 1
With the pointer of the center meter CM always adjusted to the zero point by the applied voltage V ₁ generated from 3, the capacitance value CD ₂ of the variable capacitance diode D ₂ is successively changed as a parameter, and the harmonic distortion rate is measured. By doing so, it is possible to detect the stage where the harmonic distortion rate is minimum.

Therefore, the applied voltage V ₂ applied to the variable capacitance diode D ₂ at the stage of the minimum harmonic distortion factor is memorized, the capacitance value of the variable capacitance diode D ₂ is defined by this stored applied voltage V ₂ , and further, By defining the capacitance value of the variable capacitance diode _D1 with the applied voltage _V1 through the feedback control action of the feedback control circuit 13, the zero point of the pointer of the center meter CM can be adjusted to the zero point and the harmonic distortion rate can be minimized in an extremely short time. It is possible to adjust the distortion rate to

On the other hand, the present invention is not limited to the above-mentioned embodiments, but can take various modified embodiments.

FIG. 2 shows a block diagram showing the main parts of an automatic adjustment system in which the automatic adjustment method of the second embodiment of the present invention is used. As shown in the characteristic curve L ₂ in Figure 4, the variable capacitance diode D ₂
When changing the capacitance value CD ₂ as a parameter,
If there are multiple minimum values, the center meter
This is extremely effective when attempting to complete the zero point adjustment of the CM pointer and the distortion rate adjustment to minimize the harmonic distortion rate THD in a short time.

Descriptions of the same parts as in the first embodiment of the present invention shown in FIG. 1 will be omitted, and only parts having particularly different functions will be described to avoid redundant explanation.

That is, the digital signal comparison circuit 7 compares the digital signal stored in the harmonic distortion rate storage circuit 10 and the output digital signal of the analog-to-digital converter 6, and determines whether the output digital signal from the analog-to-digital converter 6 is harmonic. When the wave distortion factor is smaller than the digital signal stored in the storage circuit 10, the switch 8a,
8b to turn them ON and store the first control signal generated by the step wave function generation control circuit 2 in the control signal storage circuit 9,
The output digital signal of the analog-to-digital converter 6 is newly stored in the harmonic distortion rate storage circuit 10.

Further, the automatic adjustment method according to the second embodiment of the present invention includes the following steps.

[Step 1] First, the program control device 11 controls the staircase wave function generation control circuit 2 to supply the applied voltage V ₂₁ to the variable capacitance diode D ₂ by the storage circuit 3 and the variable voltage generation circuit 4. Then, due to the magnetic coupling M of the double-tuned detection coil, the alternating current impedance seen from the primary side of this coil changes, and the pointer of the center meter CM deviates from the zero point. This deviation is detected by the feedback control circuit 13, and the applied voltage is further adjusted to minimize this deviation.
V ₁ is applied to the variable capacitance diode D ₁ and the capacitance value of the variable capacitance diode D ₁ is defined. Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally specified, and the distortion factor of the linear integrated circuit 1 under test corresponding to state 1 on the characteristic curve _L2 in FIG. 4 is specified. Ru. The distortion factor in this state is measured by the harmonic distortion factor side constant circuit 12, converted into a digital signal by the analog-to-digital converter 6, and then transmitted through the switch 8b turned ON by the program control device 11. It is applied to the distortion factor storage circuit 10 and stored within this storage circuit 10. Furthermore, in this state, the program control device 11 similarly controls the switch 8a to be in the ON state, so that the first control signal generated by the step wave function generation control circuit 2 is stored in the control signal storage circuit 9.

[Step 2] Next, the program control device 11 similarly controls the step wave function generation control circuit 2 to apply the applied voltage V ₂₁ to the variable capacitance diode D ₂ previously in [Step 1].
Supplying a smaller applied voltage V ₂₂ . Then, the capacitance value CD ₂ of this variable capacitance diode D ₂ increases,
Therefore, due to the magnetic coupling M of the double-tuned detection coil, the alternating current impedance seen from the primary side of this coil changes, causing the pointer of the center meter CM to deviate from the zero point. This deviation is detected by the feedback control circuit 13, and an applied voltage _V1 that minimizes this deviation is applied to the variable capacitance diode _D1 , and the capacitance value of the variable capacitance diode _D1 is defined. . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally defined, and the distortion factor of the linear integrated circuit 1 under test corresponding to state 2 on the characteristic curve _L2 in FIG. 4 is defined. Ru. The distortion rate in this state is the harmonic distortion rate measuring circuit 12.
The measured signal is applied to the digital signal comparison circuit 7, and compared with the distortion factor stored in the harmonic distortion factor storage circuit 10 in [step 1].

Therefore, the strain rate measured in this [stage 2] is
Since it is smaller than the distortion rate measured in [Stage 1],
The output of the digital signal comparison circuit 7 is sent to the switch 8a.
controls to turn it ON, causes the first control signal generated by the step wave function generation control circuit 2 to be stored in the control signal storage circuit 9, and controls the switch 8b to turn it ON, The output digital signal of the analog-to-digital converter 6 is newly stored in the harmonic distortion rate storage circuit 10.

[Stage 3]...Similar to [Stage 2] [Stage 4]... [Stage 5] Similarly, the program control device 11 controls the staircase wave function generation control circuit 2 to cause the variable capacitance diode _D2 to An applied voltage V ₂₅ smaller than the applied voltage V ₂₄ in [Stage 4] is supplied. Then, the capacitance value CD ₂ of this variable capacitance diode D ₂ increases, and therefore, due to the magnetic coupling M of the double-tuned detection coil,
The alternating current impedance seen from the primary side of this coil changes, causing the pointer of the center meter CM to deviate from the zero point. This deviation is detected by the feedback control circuit 13, and the applied voltage _D1 that minimizes this deviation is applied to the variable capacitance diode _D1.
is applied to define the capacitance value of this variable capacitance diode _D1 . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally specified, and the distortion factor of the linear integrated circuit under test corresponding to state 5 on the characteristic curve _L2 in Fig. 4 is specified. .
The distortion factor in this state is measured by the harmonic distortion factor measuring circuit 12 and compared with the distortion factor stored in the harmonic distortion factor storage circuit 10 in [step 4].

Therefore, the strain rate measured in this [step 5] is:
Since it is smaller than the distortion rate measured in [Step 4],
The output of the digital signal comparison circuit 7 is sent to the switch 8a.
controls to turn it ON, causes the first control signal generated by the step wave function generation control circuit 2 to be stored in the control signal storage circuit 9, and controls the switch 8b to turn it ON, The output digital signal of the analog-to-digital converter 6 is newly stored in the harmonic distortion rate storage circuit 10.

[Step 6] Similarly, the program control device 11 controls the staircase wave function generation control circuit 2 to apply an applied voltage V ₂₆ to the variable capacitance diode D ₂ that is smaller than the applied voltage V ₂₅ in the previous [Step 5]. supply Then, the capacitance value C of this variable capacitance diode _D2 increases, and therefore, due to the magnetic coupling M of the double-tuned detection coil,
The alternating current impedance seen from the primary side of this coil changes, causing the pointer of the center meter CM to deviate from the zero point. This deviation is detected by the feedback control circuit 13, and the applied voltage V ₁ that minimizes this deviation is applied to the variable capacitance diode D _{1 .}
is applied to define the capacitance value of this variable capacitance diode _D1 . Therefore, the AC impedance seen from the primary side of the double-tuned detection coil is finally specified, and the distortion factor of the linear integrated circuit under test corresponding to state 6 on the characteristic curve _L2 in Fig. 4 is specified. .
The distortion rate in this state is measured by the harmonic distortion rate measuring circuit 12, and in [step 5] the harmonic distortion rate storage circuit 1
It is compared with the distortion factor stored as 0.

Therefore, the strain rate measured in this [step 6] is
Since it is larger than the distortion rate measured in [Step 5],
The output of the digital signal comparison circuit 7 is connected to a switch 8a,
8b and turn them off. Therefore, the harmonic distortion rate storage circuit 10 stores the distortion rate in the [stage 5] state and does not store the distortion ratio in the [stage 6] state. Further, the control signal storage circuit 9 also stores the first control signal in the state of [stage 5] and does not store the first control signal in the state of [stage 6].

[Stage 7]... Same as [Stage 6] [Stage 8]... 〃 [Stage 1]... 〃 [Stage M] After each stage from [Stage 1] to [Stage 1] above has passed, Control signal storage circuit 9
The first control signal in [Stage 5] is stored in the harmonic distortion factor storage circuit 10, and the distortion factor in [Stage 5] is stored in the harmonic distortion factor storage circuit 10. Therefore, in this [stage m], the program control device 11 controls the switch 8c to be in the ON state and the switch 8d to be in the OFF state. Therefore, the first control signal in [Stage 5] stored in the control signal storage circuit 9 is transferred to the storage circuit 3 and stored therein, and further, this storage circuit 3 controls the variable voltage generation circuit 4 to perform the [Stage 5]. ] is applied to the _variable capacitance diode D ₂ . Therefore, just as in the case of [Stage 5], the distortion factor is adjusted to the minimum state, and the deviation of the pointer of the center meter CM from the zero point is minimized by the feedback control action of the feedback control circuit 13. applied voltage V ₁
is applied to the variable capacitance diode _D1 .

After this, the program control device 11 switches S ₁
and S ₂ are switched from the 1st side to the 2nd side, respectively.

Then, just like in the case of the first embodiment of the present invention described above, the analog-to-digital converter 6
converts the applied voltage V ₁ previously applied to the variable capacitance diode D ₁ into a digital signal, and the storage circuit 16 stores this digital signal. This storage circuit 16 is controlled by a program control device so that its stored contents do not change even if the output digital signal of the analog-to-digital converter 6 is subsequently converted. Furthermore, the variable voltage generation circuit 17 generates a DC voltage having the same voltage value as the previously applied voltage V ₁ in response to the digital signal stored in the memory circuit 16, and changes the capacitance value of the variable capacitance diode D ₁ to Maintain the state where the deviation of the center meter CM pointer from the zero point is minimized. In this way, even if the input signal conditions etc. of the linear integrated circuit under test 1 change,
The applied voltages V ₁ and V ₂₅ in the holding state do not change and are kept constant.

Next, the applied voltage under the condition that this holding state is maintained is
With V ₁ and V ₂₅ applied to the variable capacitance diodes D ₁ and D ₂ respectively, the characteristics of the linear integrated circuit 1 to be tested, such as the distortion rate, S/N ratio, and AM rejection ratio, are measured, and the Determines whether the linear integrated circuit under test is good or bad.

The present invention is not limited to the above two embodiments, but can take various embodiments.

For example, instead of the variable capacitance diode of the double-tuned detection coil, a variable inductance whose impedance changes depending on the rotation angle of the core may be used.
In this case, the rotation angle can be controlled by a motor or the like.

In addition to adjusting the zero point and distortion rate of the pointer of the center meter M of the linear integrated circuit for the FM IF system, the present invention also provides electronic The respective values of the first characteristic parameter and the second characteristic parameter of the electronic circuit, where the respective values of the first characteristic parameter and the second characteristic parameter of the circuit change while being influenced by each other, are set to respective desired values. This can be applied when trying to set the deviation to a substantially minimum state in a short time.

[Brief explanation of the drawing]

FIGS. 1 and 2 are block diagrams showing the main parts of an automatic adjustment system in which the automatic adjustment method of the embodiment of the present invention is used, and FIG.
Figure 4 shows the deflection of the pointer in response to detuning from the reception tuning frequency of the center meter CM of the linear integrated circuit for the FM IF system. Figure 5 shows the harmonic distortion factor of the FM demodulated output that changes in response to the capacitance change of _the variable capacitance diode D _{2 .} The waveform diagram is shown. 1... Linear integrated circuit for FM IF system under test, 2... Step wave function generation control circuit, 3... Memory circuit, 4... Variable voltage generation circuit, 6... Analog-digital converter, 7... Digital signal comparison circuit, 8a, 8b, 8c, 8d... switch, 9...
... Control signal storage circuit, 10 ... Harmonic distortion storage circuit, 11 ... Program control device, 12 ... Harmonic distortion measurement circuit, 13 ... Feedback control circuit, 14, 15 ... Impedance converter, 16
...Memory circuit, 17...Variable voltage generation circuit, 19
... Digital signal comparison circuit, 20 ... Harmonic maximum distortion rate storage circuit, C ₁ , C ₂ , C ₃ , C ₄ , C ₅ ... Capacitor, D ₁ , D ₂ ... Variable capacitance diode, L ₀ ,
L ₁ , L ₂ ... Coil, CM ... Center meter,
S ₁ , S ₂ ... switch.

Claims (1)

[Scope of Claims] 1. In response to changes in the first variable setting parameter and the second variable setting parameter, the respective values of the first characteristic parameter and the second characteristic parameter of the electronic circuit change while being influenced by each other. An automatic adjustment method for an electronic circuit for setting respective values of the first characteristic parameter and the second characteristic parameter of the electronic circuit to a state in which deviation from each desired value is substantially minimized. at least a first measuring means for measuring the value of the first characteristic parameter, a second measuring means for measuring the value of the second characteristic parameter, and the above measurement output signal of the first measuring means. a first characteristic parameter comparison and detection means for detecting a deviation of the first characteristic parameter from the desired value; and a first measurement parameter comparison and detection means for controlling the first variable setting parameter using a comparison detection signal of the first measurement parameter comparison and detection means. a feedback control path configured to minimize the deviation of the value of the first characteristic parameter from the desired value of the first characteristic parameter; a first control signal for controlling the value of the second variable setting parameter; The first occurrence
a control signal generating means, a second characteristic parameter storage device for storing a signal corresponding to the value of the second characteristic parameter, and a first control for storing a first control signal generated by the first control signal generating means. a signal storage device, a signal comparison means for comparing the signal stored in the second characteristic parameter storage device and the signal corresponding to the value of the second characteristic parameter detected by the second measuring means, and the first Utilizing a program control device for program-controlling at least the control signal generation means, the program control device sequentially program-controls the first control signal generation means to generate first control signals having different values sequentially;
While sequentially changing the values of the two variable setting parameters, at each stage under the sequential control of the program control device, the above values of the first characteristic parameter are changed by the control action of the first variable setting parameter of the feedback control path. The deviation of the value of the first characteristic parameter from the desired value is minimized, and the second characteristic parameter is detected by the second measuring means after the change in the second characteristic parameter due to the change in the first variable setting parameter has ended. By comparing the signal corresponding to the value of the second characteristic parameter with the signal detected in the previous step and stored in the second characteristic parameter storage device by the signal comparing means, the signal corresponding to the value of the second characteristic parameter is compared. The second characteristic parameter is determined by detecting a signal closer to the desired value of the two characteristic parameters, and sequentially advancing the measurement and control steps over a predetermined range under program control of the program control device. detecting a step in which the deviation of the value of the second characteristic parameter from the desired value is substantially minimal; storing a first control signal generated by the first control signal generating means at a minimum stage; and storing a first control signal generated by the first control signal generating means at a minimum stage;
The value of the second variable setting parameter is set by the first control signal stored in the control signal storage device, and the value of the second variable setting parameter is set by the feedback control path based on the comparison output signal of the first characteristic parameter comparison and detection means. By setting the value of the first variable setting parameter, each value of the first characteristic parameter and the second characteristic parameter of the electronic circuit is set to a state in which deviation from the desired value is substantially minimized. An automatic adjustment method for electronic circuits characterized by the ability to set settings. 2. In the electronic circuit automatic adjustment method according to claim 1, the value of the first variable setting parameter is set by the impedance of the first variable impedance means, and the value of the first variable setting parameter is set by the impedance of the second variable impedance means. An automatic adjustment method for an electronic circuit characterized in that a value of a setting parameter is set.