Fundamental design consideration of sampling circuit

This paper discusses a theoretical issue of a sampling circuit to maximize SNR while keeping its bandwidth constant, in order to realize a wideband large dynamic range sampling circuit for communication system and measuring instrument applications. We consider two time-constants τ1, τ2 in the sampling circuit, where is a product of (signal source internal impedance + sampling switch on-resistance) and (hold capacitance), and τ2 is a sampling time window (aperture time). We have derived that τ2 = 1.50τ1 is the condition to maximize SNR keeping the bandwidth constant. We will call it as a strobe sampling circuit when τ2 = 1.50τ1 is realized.