JPS6130812A - Josephson sampling circuit - Google Patents

Abstract

PURPOSE:To obtain an output signal obtained from a sampling gate circuit by using a part of a signal current from a signal current source while inputting it as a trigger signal current of the sampling gate circuit. CONSTITUTION:A trigger signal current IT and a switching DC current TD are fed to control lines C1, C2 of superconduction quantum interferrometer 2 comprising a Josephson element together with a bias current IB to generate a sampling pulse current IP from a sampling pulse generating circuit 1. The sampling pulse current IP and a sampling DC current IS are fed to control lines C2, C3 of the superconduction quantum interferrometer 6 in the sampling gate circuit 5 to output an output signal voltages VS. A signal current S is fed from a signal current source 4 to the control line C3 of the circuit 1 and the control line C1 of the circuit 5 so as to suppress the effect of variance of the signal current S.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in Josephson sampling circuits constructed using Josephson elements.

BACKGROUND OF THE INVENTION As a deliberate Josephson sampling circuit using a Josephson element, one having the configuration described below with reference to FIG. 1 has been proposed.

In other words, the bias current I is intermittent with a scheduled period.
It has a sampling pulse generation circuit 1 connected to a bias power supply terminal TB from which S is obtained through a resistor R1, and therefore repeatedly operated by a bias current IB obtained from the bias power supply terminal TB to generate a sampling pulse current IP. .

In this case, the sampling pulse generation circuit 1 is a Josephson element (not shown) having two control lines C1 and C2.
The superconducting quantum interferometer 2 has a configuration in which a trigger signal current I from a trigger signal source terminal TT is supplied to the control line C1 via a variable delay circuit 3, and
A switching DC current ID from a switching DC source terminal TD is supplied to the control line C2,
Further, a sampling pulse current IP is obtained from the superconducting quantum interferometer 2 via a Josephson probe J.

Note that R2 is a resistor inserted into the control line C1 as necessary.

Further, the signal current S from the signal current source 4, the sampling pulse current IP from the sampling pulse generation circuit 1 described above, and the sampling DC current Is from the sampling DC source terminal TS are input, and the bias voltage It has a sampling gate circuit 5 which is operated by the current IB, generates the above-mentioned sampling pulse of the signal current S from the signal current source 4, and outputs an output signal voltage vS sampled by the sampling pulse current IP from the circuit 1.

In this case, the sampling gate circuit 5 has three control I
It is connected to the above-mentioned bias power supply terminal TB through a resistor R3 having l-wires C1, C2, and C3, and has the configuration of a superconducting quantum interferometer 6, and a signal from the signal current source 4 is connected to the control line C1. A current S is supplied, a sampling pulse current IP from the sampling pulse generation circuit 1 is supplied to C2 via a resistor R5, a sampling DC current Is is supplied to the control mwaC3, and the output signal voltage v
S is outputted from the superconducting quantum interferometer 6.

Further, the signal current source 4 is connected to the above-mentioned bias power supply terminal TB via the resistor R4, and is supplied with the trigger signal current IT from the above-mentioned trigger signal source terminal TT, so that the trigger signal current T is input, the circuit is operated by bias current IB from bias power supply terminal TB, and outputs signal current S.

The above is the configuration of a conventionally proposed Josephson sampling circuit.

According to the Josephson sampling circuit having such a configuration, although detailed explanation is omitted, the sampling pulse current I from the sampling pulse generation circuit 4 of the signal current S from the signal current source 4 is output from the sampling gate circuit 5.
The output signal voltage vS sampled by P can be obtained by adjusting the level of the sampling DC current Is from the sampling DC source terminal TS.

The invention attempts to solve the problem.

However, in the case of the conventional Josephson sampling circuit shown in FIG. Since fluctuations occur in the sampling pulse current IP obtained from the pulse generation circuit 1 with respect to the signal current S, the output signal voltage VS obtained from the sampling gate circuit 5 cannot be obtained with high precision.

Furthermore, in the case of the conventional Josephson switching circuit shown in FIG. However, in the case of a circuit that operates at room temperature, the signal current S fluctuates due to thermal noise, and therefore the output obtained from the sampling gate circuit 5 This method has a disadvantage in that the signal voltage S is affected by fluctuations in the signal current S and cannot be obtained with high precision.

1 - Therefore, the present invention seeks to propose a new Josephson sampling circuit which does not have the above-mentioned drawbacks.

In the Josephson sampling circuit according to the present invention, as in the case of the conventional Josephson sampling circuit described above in FIG. The sampling pulse generation circuit includes a Josephson element that repeatedly operates to generate a sampling pulse current.

In addition, the signal current from the signal current source, the sampling pulse current from the sampling pulse generation circuit, and the sampling DC current are input, and the sampling pulse current of the signal current from the signal current source is operated by the bias current. It has a sampling gate circuit configured using a Josephson element that outputs an output signal sampled by.

However, according to the Josephson sampling circuit according to the first invention of the present application, in the above-described configuration, a part of the signal current from the signal current source is inputted to the sampling pulse generation circuit as its trigger signal current. It is done like this.

Further, according to the Josephson sampling circuit according to the second invention of the present application, in the above-described configuration, the signal current from the signal current source is input to the sampling gate circuit via the delay circuit, and the signal current source is inputted to the sampling gate circuit via the delay circuit. A part of the signal current from the current source is sent to the sampling pulse generation circuit,
It is designed to be input as the trigger signal current.

Further, in the Josephson sampling circuit according to the third invention of the present application, in the above-described configuration, a part of the signal current from the signal current source is supplied to the sampling pulse generation circuit via the switch circuit for its first trigger. The signal current is inputted as a signal current, and a second trigger signal current is inputted to the sampling pulse generation circuit.

Function According to the Josephson sampling circuit according to the present invention described above, although detailed explanation is omitted, as in the case of the conventional Josephson sampling circuit described above in FIG. It is clear that the output signal of the signal current sampled by the sampling pulse current from the sampling pulse generation circuit can be obtained by adjusting the level of the sampling direct current.

However, in the case of the Josephson sampling circuit according to the first invention of the present application, a part of the signal current from the signal current source is inputted to the sampling pulse generation circuit as the trigger signal current. Even if the signal li flow from the signal current source fluctuates with respect to the trigger signal current, the sampling pulse current obtained from the sampling pulse generation circuit does not fluctuate with respect to the signal current.

Furthermore, when the signal current source is constructed from a circuit that operates at room temperature, even if fluctuations occur in the signal current due to thermal noise, etc., the output signal obtained from the sampling gate circuit is not affected by

Further, according to the Josephson sampling circuit according to the second invention of the present application, in addition to obtaining the same effect as the above-mentioned Josephson sampling circuit according to the first invention of the present application, it has a delay circuit, so that it is difficult to adjust the delay circuit. Therefore, even when the signal current is at a sufficiently small level, an output signal can be obtained from the sampling gate circuit.

Furthermore, according to the Josephson sampling circuit according to the third invention of the present application, by turning on the switch circuit, the same effect as in the case of the Josephson sampling circuit according to the first invention of the present application can be obtained; By turning off the circuit, an effect similar to that of the conventional Josephson sampling circuit described above in FIG. 1 can be obtained, and in this case fluctuations in the signal current can be measured.

Effects of the Invention According to the Josephson sampling circuit according to the first invention of the present application, the output signal obtained from the sampling gate circuit can be obtained with high precision.

Further, according to the Josephson sampling circuit according to the second aspect of the present invention, an output signal can be obtained from the sampling gate circuit even if the signal current has a sufficient level.

Furthermore, according to the Josephson sampling circuit according to the third invention of the present application, it is possible to selectively obtain the output signal obtained from the sampling gate circuit with high precision and measure the fluctuation of the signal current.

Embodiment 1 FIG. 2 shows a first embodiment of a Josephson sampling circuit according to the present invention.

In FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The Josephson sampling circuit according to the present invention shown in FIG. 2 is different from the conventional Josephson sampling circuit shown in FIG. Gate circuit 5
Also, a part of the signal current S from the signal current source 4 is input to the variable delay circuit 6 and the switch circuit 7.
The configuration is similar to that described above with reference to FIG. 1, except that the input signal is input to the sampling pulse generation circuit 1 via the sampling pulse generating circuit 1.

The above is the configuration of the embodiment of the Josephson sampling circuit according to the present invention. According to such a configuration, it has the same configuration as described above in FIG. 1 except for the matters mentioned above. Although a detailed explanation will be omitted, the same functions and effects as described in the section of the above-mentioned functions and effects of the invention can be obtained.

Embodiment 2 Next, a second embodiment of the Josephson sampling circuit according to the present invention will be described with reference to FIG.

In FIG. 3, parts corresponding to those in FIG. 2 are designated by the same reference numerals.

In the Josephson sampling circuit according to the present invention shown in FIG. 3, a sampling pulse generation circuit 1 includes a superconducting quantum interferometer 9 having control lines 01 to C3 in front of a superconducting quantum interferometer 2. A wave current generating circuit 10 is provided, and a signal current source 4 is connected to the control line C3 of the superconducting quantum interferometer 9 via a variable delay circuit 6 and a switch circuit 7.
In the case of FIG. 3, the signal current S is supplied from the superconducting quantum interferometer 2, and the sawtooth wave from the sawtooth wave generation circuit 10 is supplied to the control line C3 of the superconducting quantum interferometer 2. It has a similar configuration.

In the case of FIG. 3, the control line C1 is omitted in the superconducting m-son interferometer 2 in the sampling pulse generation circuit 1, and accordingly, the control line C1 in the superconducting Φ-son interferometer 9 in the sawtooth wave generation circuit 10 is omitted. A trigger signal current IT and a DC current ID' from a DC power supply terminal TD' are input to the control lines C1 and C2, respectively.

The above is the configuration of another embodiment of the Josephson sampling circuit according to the present invention, which has the same configuration as the Josephson sampling circuit according to the present invention described above in FIG. 2, except for the matters mentioned above. Although detailed explanation will be omitted, the same operation and effect as in the case of FIG. 3 can be obtained.

Note that the above description merely shows a few embodiments of the present invention, and various modifications and changes may be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing a conventional Josephson sampling circuit. FIG. 2 is a connection diagram showing an embodiment of the Josephson sampling circuit according to the present invention. FIG. 3 is a connection diagram showing another embodiment of the Josephson sampling circuit according to the present invention.

Claims (1)

[Claims] 1. It is constructed using a Josephson element that repeatedly operates with a bias current that is intermittent at the same cycle as a signal from a signal current source that operates repeatedly at a predetermined cycle to generate a sampling pulse current. a sampling pulse generation circuit that receives the signal current from the signal current source, the sampling pulse current from the sampling pulse generation circuit, and the sampling DC current as input, and is operated by the bias current to generate the signal current. A Josephson sampling circuit comprising a sampling gate circuit configured using a Josephson element that outputs an output signal sampled by the sampling pulse current of the signal current from the signal current source, a portion of the signal current of the signal current source. is input to the sampling pulse generation circuit as a trigger signal current thereof. 2. A sampling pulse generation circuit configured using a Josephson element that repeatedly operates using a bias current that is intermittent at the same cycle as a signal from a signal current source that operates repeatedly at a predetermined cycle to generate a sampling pulse current. , with the signal current from the signal current source, the sampling pulse current from the sampling pulse generation circuit, and the sampling DC current as inputs, operates with the bias current, and generates the signal current from the signal current source. A Josephson sampling circuit including a sampling gate circuit configured using a Josephson element that outputs an output signal sampled by the sampling pulse current, wherein the signal current from the signal current source passes through a delay circuit, The signal current of the signal current source is input to the sampling gate circuit, and a part of the signal current of the signal current source is input to the sampling pulse generation circuit as a trigger signal current. son sampling circuit. 3. A sampling pulse generation circuit configured using a Josephson element that repeatedly operates with a bias current that is intermittent at the same cycle as a signal from a signal current source that operates repeatedly at a predetermined cycle to generate a sampling pulse current. , with the signal current from the signal current source, the sampling pulse current from the sampling pulse generation circuit, and the sampling DC current as inputs, operates with the bias current, and generates the signal current from the signal current source. In the Josephson sampling circuit including a sampling gate circuit configured using a Josephson element that outputs an output signal sampled by the sampling pulse current, a portion of the signal current from the signal current source passes through the switch circuit. through which the first trigger signal current is input to the sampling pulse generation circuit, and the second trigger signal current is input to the sampling pulse generation circuit. A Josephson sampling circuit featuring: