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IEEE Transactions on Applied Superconductivity

Error Detection Method for RSFQ Voltage Multipliers Using a SQUID Detector

Fuminori Hirayama, Masaaki Maezawa, Motohiro Suzuki, M. Ochiai

Published Jun 1, 2005• 1 citation
Publisher

Abstract

The voltage multiplier (VM) is a principal component in high-precision digital-to-analog (D/A) converters based on rapid single flux quantum (RSFQ) circuits. Experimental confirmation of correct operation of the VM is important to guarantee the accuracy of the D/A converter. In this study, a circuit for direct comparison of the output voltages of VMs was designed and demonstrated. An on-chip SQUID sensor was utilized to detect the VM errors. Bit error rates of a single-stage VM were successfully measured down to 10/sup -12/ in the constant-voltage regions. A method of detecting errors during transients was also proposed and carried out.

DOI
10.1109/tasc.2005.849850

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The voltage multiplier (VM) is a principal component in high-precision digital-to-analog (D/A) converters based on rapid single flux quantum (RSFQ) circuits. Experimental confirmation of correct operation of the VM is important to guarantee the accuracy of the D/A converter. In this study, a circuit for direct comparison of the output voltages of VMs was designed and demonstrated. An on-chip SQUID sensor was utilized to detect the VM errors. Bit error rates of a single-stage VM were successfully measured down to 10/sup -12/ in the constant-voltage regions. A method of detecting errors during transients was also proposed and carried out.
We are developing a digital-to-analog (D/A) converter based on rapid single flux quantum (RSFQ) logic circuits. Since the RSFQ D/A converter operates according to the Josephson frequency–voltage relationship, arbitrary waveforms can be synthesized with an accuracy equivalent to that of the Josephson dc voltage standard. We have examined the characteristics of magnetically coupled voltage multipliers (VMs). The VM is a key component in the RSFQ D/A converter for use in metrological applications.
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Digital to analog converters based on the Josephson effect are promising for voltage standards, because they produce voltage steps with ultimate precision and stability. In this paper, we describe a project to develop a Josephson D/A converter designed for synthesizing a sinusoidal waveform with metrological accuracy. The D/A converter is based on RSFQ (Rapid Single Flux Quantum) logic circuits, and consists of a frequency multiplier (FM), a pulse distributor (PD), and a number of voltage multipliers (VMs). Each VM circuit, corresponding to the n-th bit digital code, multiplies the number of SFQ pulses by a factor of 2/sup n/. By gating the input SFQ pulses from the FM to the VMs using the PD circuits, a programmable output voltage is obtained. Possible sources of uncertainties in the measurement of the rms value of the synthesized sine wave are discussed.
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