JP3133364B2 - Squarer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD This invention relates to electronic devices and, more particularly, to devices having a square law transfer characteristic for use in non-linear circuits.

[0002]

BACKGROUND ART An electronic device having a square law transfer characteristic, a so-called squarer, is an ideal device for theoretical study of a nonlinear circuit. Such ideal devices have been written, for example, by technical staff of Analog Devices, Inc.
4 Non-linear Circuit Handbook (non-linear
circuit handbook) ".

The transfer characteristics of such an ideal device can be described by the following mathematical formula. Uo = HUi ² (1) where Uo represents an output voltage, Ui represents an input voltage, and H is a constant.

[0004] To date, such ideal devices continually sought by the public have not been realized satisfactorily in reality, and the performance of real square law devices still leaves much room for improvement. It is. "Wide band multiplier" invented and filed by the same inventor as the applicant of the present invention (Chinese Patent No. CN1)
No. 003319513, filed on July 25, 1986, 1
The patent entitled "Notice Feb. 1, 989, Approved May 31, 1989" is a major step toward realizing such an ideal device.

In this wide band multiplier, the reverse breakdown characteristic of the reverse diode is used as the conduction direction showing zero feedthrough conduction characteristic, and the "dead zone" of the same diode forward conduction characteristic is used as the shielding direction. This is based on the concept that the peak currents of a pair of backward diodes compensate each other for the respective reverse conduction currents of these individual diodes. A multiplier constructed according to this concept exhibits a transfer characteristic in which the output current of the multiplier is substantially proportional to the square of the input voltage within a certain dynamic range. That is, this is i = k
with the characteristics of the u ^2. Where u is the input signal voltage and i
Is the output signal current, and k is a constant. However, this multiplier still has the following defects. That is, the upper part of the transfer characteristic curve deviates significantly from the square law, thus greatly limiting the dynamic range of the device. C. Signal and D.S. C. The difference between the transfer characteristics of the signals is large; moreover, the output circuit to be connected to the output of the multiplier must be driven by the output current of the multiplier.

It is an object of the present invention, therefore, to provide a square law device, and more particularly, a squarer that is very close to ideal square law characteristics. That is, the transfer characteristic of the squarer according to the present invention is exactly square-law characteristic (ie, Uo = Kui ² , where Ui is the input signal voltage, Uo is the output signal voltage, and K is a constant) within a fairly wide dynamic range. Match; C. Applies to the frequency range from to the microwave frequency band.

Another object of the present invention is to provide a squarer which can be used in various output circuits and has the above excellent characteristics.

It is still another object of the present invention to provide a low cost squarer having the above excellent characteristics.

[0009]

SUMMARY OF THE INVENTION In order to achieve these objects, improvements have been made to the above-mentioned patent CN 100003195B. According to the present invention, a resistor R having a selected resistance
Is added to compensate for the upper portion of the reverse conduction characteristic of the reverse diode, and the resulting characteristic exactly matches the square law. When the lower part of the reverse conduction characteristic of the reverse diode is compensated by the peak current of another reverse diode, the upper part of the reverse conduction characteristic of the same reverse diode also has the selected resistance according to the invention. Can be compensated by adding a resistor having In this way, the above-mentioned disadvantages of the prior art are overcome, so that the squaring device according to the invention has a square-law characteristic within a much wider dynamic range than that of the prior art. According to this application, the output of the squarer of the invention is
Can be connected to a capacitor or frequency selection circuit. Optionally, these two output terminals O and O 'can be short-circuited, so that the output signal is obtained directly through the two ends of the compensation resistor R. The output voltage from the capacitor or the frequency selection circuit connected to it, or the compensation resistor (when the terminals O and O 'are short-circuited)
It is proportional to the square of the input signal voltage and therefore the squarer according to the invention has a transfer characteristic of Uo = KUi ² .

[0010]

FIG. 1 shows one embodiment of the squarer of the present invention, which comprises two reverse diodes D.
1 and D2, and one compensating resistor having a selected resistance. The cathode of the diode D1 is connected to the anode of the diode D2, and one end of the compensation resistor R is connected to the diode D1.
The other end of the compensation resistor R is connected to one output of the squarer. The basic principle of operation of this squarer will be described below.

The reverse breakdown characteristic of the reverse diode D1 has a zero feedthrough conduction characteristic as shown by a dotted line in the first quadrant of FIG. However, this characteristic curve deviates greatly from the square law. To solve this problem, in this embodiment, when diode D1 is in reverse conduction, diode D2 is in forward conduction, so that the peak current of diode D2 is less than diode D2.
1 is provided to compensate for the lower part of the current-carrying characteristic curve, so that the lower part of this combined characteristic curve exhibits accurate square law characteristics. Further in accordance with the resistor compensation method of the present invention, resistor R having the selected resistance of FIG. 1 is used to compensate for the upper portion of the reverse conduction characteristic curve of reverse diode D1, resulting in a characteristic curve. Also shows the exact square law shape. Thus,
The resulting overall characteristic curve of the squarer of this embodiment is very high from the zero feedthrough point to a very high level, as shown by the solid line in the first quadrant of FIG. It has a square law characteristic within a wide dynamic range. By the way, in some applications,
It is not necessary to have a strict square law characteristic, so the diode D2 is eliminated. In this case, the lower part of the squarer characteristic deviates somewhat from the square law.

The squarer shown in FIG. 1 can be used for many applications. In accordance with these applications, the user would change the corresponding circuit from the line in FIG.
Connected to output terminals O and O 'as shown by
When these terminals are connected to a capacitor having an appropriate capacitance, D.C. A C signal or a low frequency signal is obtained via a capacitor. In the case where the user seeks to obtain an output signal at a specific frequency, for example, twice the frequency of the input signal Ui, or when the user attempts to obtain the upper sideband frequency signals of the input signals Ua and Ub. In that case, a corresponding frequency selection circuit or filter designed for these purposes is connected to these terminals O and O 'so as to obtain the required output signal. When the terminals O and O 'are short-circuited, a signal including all the frequency components within the square law characteristic generated by the squarer of the present invention is obtained from the two terminals of the compensation resistor R. In all the cases described above, the voltage value of the output signal is proportional to the square of the input signal voltage.

FIG. 2 shows another embodiment of the present invention. This is a two-quarter squarer. The lower part of the reverse conduction characteristic of D1 is compensated by the peak current of D2,
Similarly, the lower part of the reverse conduction characteristic of D2 is compensated by the peak current of D1, and two compensating resistors R with selected resistances are used to compensate for the upper part of these characteristic curves. In this way, the compensated transfer characteristic curve shows an accurate square law characteristic as shown by the solid line in FIG.

Similarly, various multiple-quadrant squarers can be formed. That is, according to the present invention, a new type of squarer can be formed in a series having the following advantages.

That is, X. The uncertainties on the Y axis are reduced; they have a square law characteristic within a very wide dynamic range, can operate in a very wide frequency band,
Furthermore, they have the performance of fast response, low noise and good thermal stability. In addition, the inputs and outputs of the squaring device of the present invention can be designed as balanced terminals or unbalanced terminals, and a single signal or a plurality of signals can be applied to the input of the squaring device according to the present invention. Further, the transfer characteristic of the squarer of the present invention can be described in the form of the above-described equation (1) in analyzing a nonlinear circuit. For example, two signals U
If a and Ub are input in balanced form to a 4-quadrant squarer, the output signal of this squarer is approximately equal to the pure product of Ua and Ub. This eliminates the need to expand the transfer function in the power series in the analysis of the relevant non-linear circuit, which simplifies the frequency selection or the selection of the filtering circuit, for example, a certain filtering circuit can be omitted, and the square of the present invention Because of the zero feed-through characteristics of the device, a new method (low-level design method) is provided for the design of circuits containing the squarer of the present invention. Using this method, the gain of the preceding stages of the circuit system can be reduced, and most of the gain of the entire system can be distributed to the later stages of the system.

The series of squarers of the present invention provides a simple and simple method and apparatus for measuring electronic signal power, true effective value and noise with high accuracy, and provides frequency conversion and good performance with good performance. Can be used for phase conversion.

While the preferred embodiment of the invention has been described, it is to be noted that the invention is not limited to this, and departs from the spirit and scope of the invention. Accordingly, the invention and all such changes and modifications are intended to be limited only by the appended claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the circuit of a 1-quarter squarer according to the present invention and its connection to an output circuit to be connected.

FIG. 2 is a schematic diagram of a circuit of a 2-quadrant squarer according to the present invention.

FIG. 3 shows a characteristic curve of a so-called ideal squarer.

FIG. 4 shows the compensation of the reverse conduction characteristics by adding a resistor with a selected resistance according to the invention.

FIG. 5 shows a transfer characteristic curve in two quadrants with a combination of reverse diode compensation and resistor compensation of a selected resistor according to the present invention.

[Explanation of symbols]

 D1, D2 Reverse diode R Compensation resistor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06G 7/20 H03G 11/02 H04N 5/202

Claims (1)

(57) [Claims] 1. A first reverse diode (D1) having an anode and a cathode; a resistor (R) having one end connected to the anode of the first reverse diode and having the other end; A second reverse diode (D2) having an anode connected to the cathode of the reverse diode and having a cathode, and an input for applying an input voltage (Ui) between the anode and the cathode of the second reverse diode. A terminal means, wherein an output voltage (Uo) from the cathode of the second reverse diode to the other end of the resistor is Uo = KUi ² where K is a constant. vessel.