The Stanford Research Systems FS735-1-1 is a dual-amplifier distribution system housed in a 19-inch rack-mount chassis. It provides two independent signal paths, each with seven output channels, for a total of fourteen BNC-terminated outputs. This configuration allows simultaneous distribution of 10 MHz frequency references and CMOS logic pulses with maintained signal integrity and low phase noise.
Technical Specifications
-# Physical Configuration
• Chassis: 19-inch rack-mount enclosure (FS735 series)
• Inputs: 2 independent channels
• Outputs: 14 total (7 per amplifier)
• Connectors: BNC on all inputs and outputs
-# 10 MHz Distribution Amplifier
• Signal: Low-noise 10 MHz sine wave reference
• Input coupling: AC coupled with series LC network for DC offset accommodation
• Input source impedance: 50 Ω at 10 MHz
• Input conditioning: Limiter removes amplitude modulation, fixes output amplitude, blocks noise >50 mV from zero-crossing
• Signal path: Limiter → bandpass filter → fixed gain amplifier
• Output amplitude (50 Ω load): 1 Vrms (+13 dBm); adjustable to 2.82 Vpp
• Output source impedance: 50 Ω
-# CMOS Logic Distribution Amplifier
• Signal: Logic-level pulses
• Input impedance: 1 kΩ
• Schmitt trigger threshold (low to high): +1.3 VDC
• Hysteresis: 0.35 V
• Output levels: 0 VDC and 5.0 VDC
• Output source impedance: 50 Ω (reverse terminates reflected pulses on unterminated lines)
• Drive capability: High-impedance loads driven to 5 V; 50 Ω loads driven to 2.5 VDC
• Transition times: Fast
• Overshoot: Very low
• Output polarity: Configurable via internal jumper (non-inverting default)
• Channel isolation: High
– Key Features
• Modular FS735 chassis accommodates mixed configurations (10 MHz, 5 MHz, CMOS, broadband)
• Independent dual-channel architecture prevents crosstalk between signal paths
• Input limiting preserves frequency reference stability against varying input amplitudes
• 50 Ω output impedance provides proper termination for cable-driven loads
– Typical Applications
• Frequency reference distribution in metrology laboratories
• Clock synchronization across multiple instruments
• Precision calibration signal delivery
• Logic pulse distribution in timing-critical systems
