Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS52144902 In the distortion measurement method of input / output characteristic curve of a dual balanced connection circuit such as a balanced stereo demodulation circuit, an output BLeBR% of the dual balanced connection circuit to a certain input level B above level B The output ALeAR of the dual balanced circuit for an input level lower by a certain value and the output CI of a dual balanced circuit for an input level C higher by a value than the above input level B. Determining the distortion factor of the double balanced connection circuit by calculating OR and comparing the average value of the difference between AL and A and H and the difference between OI and CR with the difference between Bz and BR Characteristic distortion measurement method. Claims DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of measuring the distortion factor of a double balanced connection circuit combining two differential amplifiers, and in particular to the unbalance of the characteristics of differential pair transistors constituting the double balanced connection circuit. The present invention relates to a method of measuring the quality of distortion characteristics based on Generally, when measuring the linearity of the characteristic curve of a circuit, a sine wave signal is applied to the input side, harmonics are taken out with a filter on the output side, and the distortion factor is derived from the ratio of harmonics to the fundamental wave The method is used. However, in the measurement of the distortion factor by such ac measurement method, it has to be measured with a signal generator, strain gauge etc. equipped equipment, and in the case of a finished product with a completely attached terminal, in any case The measurement at the step □ is very troublesome. Therefore, measurement of the distortion factor by the direct current measurement method was tried. This is, for example, an output at an operating point level, an output O1 at an operating point level, a constant one value, an output Oa at an extremely high input level, an 10-05-2019 1 output Oc at a manual level lower by an operating point level. And 0a-Ob and Ob-Oc. If the two are equal, it is determined that there is no distortion, and it is determined that the larger the difference between the two, the larger the distortion. EndPage: 1 However, in order to directly measure the linearity with respect to such an input / output characteristic curve itself, the measurement accuracy of the measurement instrument must be extremely high. For example, in order to check whether the distortion rate conforms to the standard of 0.2% or less, a tester accuracy of about 0.02% is necessary. In accordance with the mass production pace with such a high-precision tester It is difficult and impractical to conduct a large amount of strain rate inspection. The present invention relates particularly to a method of measuring the distortion factor of a double balanced connection circuit, and the distortion factor characteristic of the double balanced connection circuit is an imbalance of the characteristics of two differential pair transistors constituting the circuit as described below. The two differential pair transistors are simultaneously set under the same bias condition, and the input / output characteristics of the double balanced connection circuit are measured to determine the distortion factor. In the case of applying the double balanced connection circuit to a stereo demodulation circuit as shown in FIG. 1, the inventor of the present invention has almost no distortion rate defect at the time of stereo signal reception, but has distortion rate defect at the time of monaural signal reception. It was found that many cases, that is, most distortion defects were distortion defects at the time of monaural signal reception, and as a result, it was clarified as follows. That is, in the case of receiving a stereo broadcast, if one of Q2 and Q4 of two switching transistors (two pairs of differential pair transistors) Q1 to Q4 is shut off, the other Q1 and Q4 are saturated, then In the moment of the moment, it is impossible that the problem of the imbalance of the transistors mutually becomes an issue at the moment, but in the case of receiving a monaural signal, the terminals A and B + are shorted and differential The same potential is applied to the input of each switching transistor, which is a pair transistor, so that the current is shared by half of the differential pair transistors. However, some characteristic differences in the differential pair transistors tend to result in deterioration of the linearity of the input / output characteristics at the time of monaural signal reception and high distortion factor when the balance becomes worse. It becomes. Figure 5 (-) and (→ are those with good distortion rate (a) and bad one (1)) to verify this, the input and output characteristic curves for each of the left and right channels in Figure 1 are examined with a curved laser It is a characteristic curve figure. As apparent from this, it can be considered that the input / output characteristics of the left and right channel do not match, and the balance of the differential pair transistors is bad when the monaural signal is received with a low distortion factor. Therefore, the distortion factor can be estimated by examining the balance of the left and right channels without strictly checking the input / output characteristic curve itself. The present invention has been made under such recognition, and an object of the present invention is to simply measure the distortion factor of the input / output characteristics of a double balanced connection circuit consisting of two sets of differential amplifiers. According to one embodiment 10-05-2019 2 of the present invention, in the distortion factor measurement method of the input / output characteristic curve of the double balanced connection circuit, the outputs BL of the left and right channels with respect to a certain input level B. BR1 For the input level A which is lower than the above level. The outputs OL and OR of the left and right channels with respect to the output ATtAR of the left and right channels and the input level 0 higher by a certain value than the above input level B are obtained, and the average value of AI, ARO difference and CI, and CR difference To determine the distortion rate by comparing the difference between BL and BR. Hereinafter, the present invention will be described based on a specific example in which a double balanced connection circuit is used for a balanced stereo demodulation circuit. FIG. 1 shows a balanced stereo demodulation circuit to be subjected to distortion measurement according to the present invention. A differential amplifier consisting of a switching transistor Q1sQ2, a load resistor RLLs RLR and an amplifying transistor Q is a cancellation circuit of a crosstalk component consisting of a switching transistor Q *, Q, a, an amplifying transistor q6 and resistors R1 to R. Provided to complete separation of the left and right channels. Ｒ４とＲ，はＱ６． Resistance that biases Qs. When receiving a stereo signal, the switch SW is on the S side, and a switching pulse vso (38KH,) is applied between the A and B terminals by superimposing on the DC reference voltage ■ R111ν applied to the A terminal, EndPage: Q2 μi is turned on and Q1 # Q4 is turned off at two timings, and Q2 pQl is turned off and Qll Q4 is turned on at the next timing. When a monaural signal is received by this stereo demodulation circuit, the switch SW is switched to the M side, and the same bias is applied to all the bases of the switching transistors Q1 to Q4 to turn them all on. As described above, when all the switching elements are turned on to receive monaural signals, for example, if there is variation in the characteristics of the switching transistor, current flows uniformly to the differential pair transistors of the differential amplifier. There is a problem of monotonic THD (Total Harmonic Distortion). As a result of measuring the input / output characteristic curve for each of the left and right channels with respect to the non-defective product which passed the monaural THD test with respect to each of the left and right channels with the curve tracer, all the former (non-defective product) The latter (defective product) is also apparent from, for example, a mismatch as shown in the figure (bl), that is, an imbalance between the left and right channels occurs. Therefore, as shown in FIG. 2, the outputs BL of the left and right channels with respect to the input B of the operating point level, the outputs ALjAR of the left and right channels with respect to the input A of the lower limit level of the BR1 dynamic range, and the left and right channels with respect to the input C of the upper limit level of the dynamic range. Measure the output CLtOR. Then, a calculated value V D representing the distortion factor is obtained by the following equation%). Then, the distortion factor is determined to be larger as the absolute value of the calculated value VD is larger. That is, the poor linearity of the input / output characteristic curve in monaural in the differential amplification type stereo demodulation circuit is due to the unbalance of the characteristics of the switching transistors forming the differential pair. Therefore, in the case where the characteristic is unbalunable, for example, having the characteristic shown in FIG. 2 as 10-05-2019 3 an example, input A (input level corresponding to upper limit of dynamic range), input B (operating point level), input C (dynamic range lower limit) If you check the output ALsARpBLsBR * CLsCR for the input level 5 that corresponds to the above, AI, AR is AR ', and, even though oL is higher than CR, BTJO is lower P) R lower It is. This indicates that the characteristic curves of both left and right channels are distorted. The distortion is considered to be thicker as the distortion is greater. That is, according to the present invention, the distortion is obtained by subtracting the difference between the left and right outputs of the operating point level at the normal time from the difference between the left and right outputs at the upper limit of the dynamic range and the difference between the left and right outputs at the lower limit. It is to estimate. Further, in the case of FIG. 3 (a) which is not caused by poor linearity, since the average value of AL-AR and aTJ-cR is equal to BL-BR, and the calculated value is approximately O, the distortion factor is defective. Is not determined. Similarly, in the case of FIG. 3 (ii), since (ALAR) + (OLOR) is 0 and BL-BR is also 0, it is determined that the distortion rate with a calculated value of 0 is not defective. As described above, the measurement method of the present invention makes it possible to distinguish between those with low distortion and those with good distortion. Of course, the cases of FIG. 3 (a) and (b) should also be distinguished from non-defective products that are defective. However, it should not be rejected in the strain rate test. Thus, according to the present invention, the quality of distortion can be determined. FIG. 4 shows the relationship between the distortion factor (MoNo, Tu: o) at the time of receiving a monaural signal and the calculated value by the distortion factor measurement according to the present invention for a semiconductor bellet in which several circuits of FIG. 1 are integrated. In the correlation diagram shown (where the abscissa is the value of the strain rate measured strictly by the strain rate measuring device and the ordinate is the calculated value measured by the measuring method of the present invention), a shows an ideal straight line. If the experiment is on the diagram, it is perfect. The further away it is from the straight line, the less complete. From this test result, it can be said that, according to the present invention, the EndPage: 3 position which is extremely close to the ideal straight line is correct even if it is not perfect. Of course, the smaller the strain 歪 value, the larger the ratio of the difference between the measured value according to the strict measurement method and the measured value according to the present invention. do not have to. Therefore, it can be said that there is virtually no difference in judging the acceptance or rejection of the distortion factor according to the present invention. According to the present invention, strain rate test can be performed only by calculation processing for measurement results at three levels, and it is necessary to measure IJ nearness of the characteristic curve strictly by dynamic measurement. The distortion factor can be easily measured. It is not necessary that the input levels A, B, 0 as measurement points correspond to the dynamic range lower limit level, the operating point level, and the dynamic range upper limit level, and A> B> 0% 6 or A (B <0 It should be O. That is, even if the level of the input cam is slightly higher than the dynamic range lower limit level, the level of C may be slightly lower than the upper limit level even if B slightly deviates from the operating point level. The present invention is not limited to 10-05-2019 4 the measurement of the distortion factor of the demodulation circuit, but is generally applied to a double balanced connection circuit consisting of two sets of nine differential amplifiers. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an example of a stereo demodulation circuit to be measured according to the present invention, and FIG. 2 is an input / output characteristic curve diagram of left and right channels in a circuit with a distortion factor failure; b) shows the input / output characteristic curves of the left and right channels showing an example of a defect that is not a defect in distortion, and FIG. 4 shows the relationship between the measured values of severe distortion for some pellets and the measured values according to the present invention It is a correlation diagram. FIG. 5 compares input / output characteristic curves of left and right channels of a non-defective product and a non-defective product regarding distortion factor, and (&) indicates a non-defective product. RLLeRLR · · · Load resistance, R1-R · · · · Resistance, Q1-Q6 · · · Transistor,-C · · · DC output, E · · power supply for bias, vco · power supply voltage, vsc · · subcarrier signal, VRIF · · DC reference voltage. Ｊキ？ ・。 Attorney Attorney Attorney 1) Toshiyuki. 1st 8c 3 c ˜ ˜) ■ Person EndPage: 4 5 5. (2) (b) input level 11 □ OOl Q-5, 1, or 5Y = I group L ')? MONO, chome U) (ヅ EndPage: ５ 10-05-2019 5

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