Demonstration of 6-bit, 0.20-mV_pp Quasi-Triangle Voltage Waveform Generator Based on Pulse-Frequency Modulation

Abstract

We present our design and operation of a 6-bit quasi-triangle voltage waveform generator comprising three circuit blocks; an improved variable Pulse Number Multiplier (variable-PNM), a Code Generator (CG), and a Double-Flux-Quantum Amplifier (DFQA). They are integrated into a single chip using a niobium Josephson junction technology. While the multiplication factor of our previous m-bit variable-PNM was limited between 2^m-1 and 2^m, that of the improved one is extended between 1 and 2^m. Correct operations of the 6-bit variable-PNM are confirmed in low-speed testing with respect to the codes from the CG, whereas generation of a 6-bit, 0.20mV_pp quasi-triangle voltage waveform is demonstrated with the 10-fold DFQA in high-speed testing.