JPS5929907B2 - computing device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a nonlinear arithmetic device.

Generally, when using amplifiers, etc., amplifiers with linear input/output characteristics are often used, but on the other hand, when creating arithmetic units or correction devices, amplifiers with nonlinear input/output characteristics are sometimes required. It often occurs.

General forms of nonlinear systems include those in which the output has a power or logarithmic relationship with the input;
Alternatively, there are things that have a power relationship, or things that have an inversely proportional relationship.

An example of a method conventionally used when creating an arithmetic device with nonlinear arithmetic characteristics will now be described with reference to FIGS. 1 and 2.

In Fig. 1, the horizontal axis shows the voltage Vi of the input signal, and the vertical axis shows the voltage Vo of the output signal.Curve 1 shows the nonlinear calculation characteristics of the arithmetic unit that is currently required, and broken line 2 shows the conventional These are the calculation characteristics obtained by the method.

FIG. 2 is a block diagram showing a conventional example of a method for creating a system having characteristics approximating the characteristics of curve 1 in FIG. 1.

In Figure 2, 3 is an input resistor, 4 is an operational amplifier with negative gain and a very large absolute value, 5 is a feedback resistor, and 6
is a resistance value controller that controls the resistance value of the feedback resistor 5, γ is an adder, 8 is a constant voltage source, 9 is an input terminal, and 10 is an output terminal.

An input signal is applied to input terminal 9 and applied to operational amplifier 4 via input resistor 3 .

The output of the operational amplifier 4 is applied to a feedback resistor 5 and a resistance value controller 6, and the resistance value of the feedback resistor 5 is controlled by the magnitude of the output voltage of the operational amplifier 4.

On the other hand, the output from the operational amplifier 4 is added to the adder 7,
The voltages applied to the adder 7 from the constant voltage source 8 are added and an output signal appears at the output terminal 10.

In this way, a system whose input/output characteristics are represented by the broken line 2 which approximates the curve 1 in FIG. 1 is obtained.

As is clear from Fig. 1, in the conventional example shown in Fig. 2, the resistance value of the feedback resistor 5 is changed in stages, so it is impossible to make the input/output characteristics a smooth curve. ,
It is not possible to create an accurate arithmetic device.

Furthermore, it is quite difficult to accurately control the resistance value of the feedback resistor 5, and once the characteristics are set, they cannot be easily changed.

On the other hand, instead of changing the resistance value of the feedback resistor 5 in steps, if a nonlinear resistor whose resistance value changes depending on the voltage applied to the resistor, such as a varistor, is used as the feedback resistor, the input/output Characteristics can be made into smooth curves.

However, the shape of the input/output characteristics depends on the nonlinear resistor used, and the shape of the input/output characteristics that can be obtained is limited to some extent.

The present invention eliminates the above-mentioned drawbacks, and has an arithmetic characteristic that is inversely proportional, that is, the voltage of the input signal is Vi (volt), the voltage of the output signal is Vo (volt), and A, B, and C are constants. It provides equipment.

An embodiment of the present invention will be described below based on the drawings.

In FIG. 3, 11 is an oscillator, 12 is a charge transfer element, 1
3 is a p-wave generator, 14 is a voltage controlled oscillator, 15 is a clock signal generator, 16 is a phase comparator, IT is an input terminal, and 18 is an output terminal.

The input signal is applied to the input terminal 17 and the voltage controlled oscillator 1
The output signal is applied to a clock signal generator 15 to create a predetermined rank waveform, which drives the charge transfer element 12 or is supplied to the charge transfer element 12 as a rank signal.

On the other hand, a constant frequency signal generated by the oscillator 11 passes through the charge transfer element 12 and is applied to the p-wave generator 13, and unnecessary frequency components are removed and the signal is supplied to the phase comparator 16.

In the phase comparator 16, a phase comparison is performed between the signal from the r-wave generator 13 and the signal from the oscillator 11, and an output signal determined by the phase difference between the two appears at the output terminal 18.

Now, the number of stages of the charge transfer device 12 in FIG. Then, the delay time T is expressed as.

However, depending on the driving method of the charge transfer element, NIN
3 fcp 4 becomes.

On the other hand, the voltage of the input signal applied to the input terminal 17 is Vi (volt), the oscillation frequency of the voltage controlled oscillator 14 is fv (hertz), and the voltage controlled oscillator 1 when the voltage Vi of the input signal is zero
When the oscillation frequency of the voltage controlled oscillator 14 is Fo (hertz) and a certain constant series Kv (1/volt), the voltage controlled oscillator 14
However, its oscillation characteristics are fv-po(1+Ky ・Vt) ・”-(51
), then from equations (50) and (51), if the delay time T is expressed by the voltage Vi of the input signal, fcp and fv are equal.

On the other hand, if the oscillation frequency of the oscillator 11 is fs (hertz), the delay phase angle φ (radian) caused by the signal generated by the oscillator 11 passing through the charge transfer element 12 is φ=2π·fs-T... ...(53)
It is.

From equations (52) and (53), the delayed phase angle φ can be expressed by the voltage Vi of the input signal.

The phase comparator 16 sets the voltage of the output signal, that is, the phase difference signal, to Vo (volts), the gain to Kp (volts/radian),
When the constant voltage is Vp (volt), it generally has a phase comparison characteristic of Vo=Kp·φ+vp (55).

From equations (54) and (55), the output signal Vo generated at the output terminal 18, ie, Vo, is expressed by the voltage Vi of the input signal.

In equation (56), f s e Kp''N and Fo are each constants. Substituting the constant K into equation (56) gives the following equation. Comparing equations (58) and (49), it is clear that both They have the same shape.

Therefore, K in formula (58) is replaced by A in formula (49), and (58
), KV in the formula (49) is replaced by B in the formula (58), and V in the formula (58) is
By setting p equal to C in equation (49), it is possible to obtain an accurate arithmetic device having arithmetic characteristics exactly equal to those shown in equation (49).

In this embodiment, as is clear from equation (57), the constant can be easily changed to an appropriate value by changing any one of Fo, N, Kp, and fs, and KV It is also possible to change.

Therefore, depending on the settings of the constants KV and Vp, the values corresponding to A, B, and C in equation (49) can be changed, and the calculation characteristics can be freely determined or changed.

In Figure 4, the horizontal axis represents the input voltage Vi, and the vertical axis represents the output voltage V.
Curve 20 shows that K is a positive constant and KV is also a positive constant, and curve 19 shows that K is a positive constant and Kv is a positive constant. The curve 21 shows the calculation characteristics when K is a negative constant and KV is a positive constant, and the curve 22 shows the calculation characteristics when K is a negative constant and Kv is also a negative constant.

Figure 4 shows the difference that occurs depending on whether the constants K and 2 are positive or negative constants.Even if the sign remains unchanged, the arithmetic characteristics can be changed by changing the absolute value. Of course it can be changed.

Naturally, the calculation characteristics can also be changed depending on how Vp is set.

Furthermore, if a sawtooth wave shown in waveform 23 in FIG. 5 whose repetition period is sufficiently larger than the delay time of charge transfer element 12 is used as an input signal to input terminal 17 in FIG. can get.

In FIG. 5, the horizontal axis indicates time t, and the vertical axis indicates the voltage Vi of the input signal and the voltage Vo of the output signal, respectively.

The slope portion 24 of the waveform 23 has the following formula: V1=P-1+Q (59) where the time is t (seconds), P and Q are constants, and the voltage of the slope portion 24 is Vl (volts).
It is indicated by.

However, when waveforms 2 and 3 are applied to the input terminal 17 in FIG. 3, the waveform appearing at the output terminal 18 becomes waveform 25 in FIG.
4 is a curved portion 26.

The voltage v2 (volts) of the curved portion 26 is clearly expressed by using certain constants R, S, and V from equations (58) and (59).

Therefore, if a sawtooth wave such as waveform 23 in FIG. 5 is used as the input signal of the embodiment of the present invention shown in FIG. It is possible.

Note that the delay element in this embodiment is not limited to a charge transfer element, but may be any element whose delay time can be controlled by the frequency of a clock signal, and the charge transfer element in this embodiment is a BBD (Bucket Brigade Device). ,
CCD (Charge Coupled Device)
), capacitor memory, etc.

FIG. 6 shows an example of a BBD using an equivalent circuit.

In FIG. 6, 27, 28, 29, 30, and 31 are transistors, and 32, 33, 34, and 35 are capacitors, each connected between the transistor and the collector.

38 and 39 are clock signal input terminals, 36 is a signal input terminal, and 37 is an output terminal.

The information added to the input terminal 36 is input to the clock signal input terminal 3.
According to the clock signals applied to 8 and 39, the signals are sequentially transferred from capacitor 32 to 33, 34.degree. 35, and then transmitted to output terminal 37.

Note that the clock signals for driving the charge transfer element shown in FIG. 6 have waveforms 40 and 41 in FIG. 7, and are applied to clock signal input terminals 38 and 39, respectively.

Although FIG. 6 shows a BBD made up of bipolar transistors, there are also BBDs made up of FETs and the like.

Naturally, the same effect can be obtained by using not only the BBD but also a COD or a capacitor memory in place of the charge transfer element 12 shown in FIG. 3.

It is also possible to replace the oscillator 11 in FIG. 3 with a rectangular wave oscillator and the charge transfer element 12 with a shift register.

That is, in FIG. 8, 42 is a square wave oscillator, 43 is a shift register, 44 is a phase comparator, 45 is a voltage controlled oscillator, 46 is a clock signal generator, 47 is an input terminal, and 48
is an output terminal, and a rectangular wave oscillator 42 applies a repeated signal of low level and bi level to a shift register 43, and its output is applied to a phase comparator 44.

Further, the rectangular wave oscillated by the rectangular wave oscillator 42 is also added to the phase comparator 44 for phase comparison, and an output signal is generated at the output terminal 48.

On the other hand, a voltage controlled oscillator 45 is controlled by an input signal applied to an input terminal 47, a clock signal is generated by a clock signal generator 46, and the clock signal is supplied to a shift register 43.

With the configuration shown in FIG. 8, the same effect as shown in FIG. 3 can be obtained.

In addition, in FIG. 8, if an analog-to-digital converter is inserted on the input side of the shift register 43 and a digital-to-analog converter is inserted on the output side, the input signal to the analog-to-digital converter can be an analog signal. The waveform to be used does not need to be a rectangular wave.

As is clear from the above examples, according to the present invention (49
) If you need an arithmetic device with the characteristics shown by the formula (4
9) It is possible to create an arithmetic device having exactly the same arithmetic characteristics as the arithmetic characteristics shown by the formula.

Moreover, it is possible to obtain an accurate arithmetic device, and it is also easy to change the arithmetic characteristics.

[Brief explanation of the drawing]

Fig. 1 is a graph showing a nonlinear calculation characteristic and the calculation characteristic according to a conventional example, Fig. 2 is a block diagram showing a conventional example for obtaining calculation characteristics approximate to nonlinearity, and Fig. 3 is an example of an embodiment of the present invention. Figure 4 is a block diagram showing the calculation characteristics obtained by the configuration shown in Figure 3. Figure 5 is an input waveform and output waveform diagram when a sawtooth wave is input. Figure 6 is an example of BBD in equal section. Circuit diagram shown in circuit, Figure 1 is BBD of Figure 6
FIG. 8 is a block diagram showing another embodiment in which a shift register is used. 11... Oscillator, 12... Charge transfer element, 13... F wave generator, 14... Voltage controlled oscillator, 15... Clock signal generator, 16
... Phase comparator, 17 ... Input terminal,
18...Output terminal, 42...Square wave oscillator, 43...Shift register, 44...
... Phase comparator, 45 ... Voltage controlled oscillator, 4
6... Clock signal generator, 47...
Input terminal, 48... Output terminal.

Claims (1)

[Claims] 1. An oscillator, a charge transfer element or shift register that receives the output of this oscillator as input, a voltage controlled oscillator whose oscillation frequency changes depending on an input signal, and a clock of the charge transfer element or shift register that uses the output of this voltage controlled oscillator as input. A clock signal generation circuit that generates a signal, and a phase that compares the phase of the signal that has passed through the charge transfer element or the signal that has passed through the shift register, with unnecessary components removed by a filter, and the signal created by the oscillator. An arithmetic device comprising a comparator circuit and using a phase difference signal output from the phase comparator circuit as an output signal.