One of the main difficulties in observing quantum coherence (MQC) in rf-SQUID based systems is extremely short coherence times. Quantum coherence in macroscopic system is rapidly destroyed by interaction with the environment. This precludes any MQC experiments from using high-speed data acquisition that allows direct evidence of coherent evolution of linear combination of rf-SQUID eigenstates. In order to perform such experiments, isolation structures that effectively shield MQC experimental elements from small-signal interaction with data acquisition circuitry on chip and at the same time allow large signals such as RSFQ pulses to propagate through. We consider design and simulation of series of Josephson junctions with varied parameters as an example of such isolation filters.