Stanford Research DS345 – 30MHz Synthesized Function Generator

The Stanford Research Systems DS345 is a 30 MHz synthesized function generator employing Direct Digital Synthesis (DDS) architecture to deliver high-precision, stable waveforms across research, development, and production environments. It generates standard waveforms (sine, square, ramp, triangle, noise), arbitrary waveforms with 16,300-point record length and 12-bit vertical resolution, and supports AM, FM, PM, and burst modulation with internal or external sources. Phase-continuous linear and logarithmic frequency sweeps, configurable burst patterns, and dual TTL/ECL outputs make it suitable for component characterization, signal integrity testing, and instrument control applications.

Technical Specifications

• Frequency range: 1 µHz to 30.2 MHz


• Frequency resolution: 1 µHz


• 48-bit phase accumulator; 40 MHz maximum phase accumulator addition rate


• Sine wave amplitude accuracy: ±0.2 dB (1 µHz–20 MHz), ±0.3 dB (20–30.2 MHz) at 5–10 Vpp; ±0.4 dB (1 µHz–20 MHz), ±0.5 dB (20–30.2 MHz) at 0.01–5 Vpp Waveform Capabilities


• Standard waveforms: sine (30.2 MHz), square (30.2 MHz), ramp (100 kHz), triangle (100 kHz), wideband noise (10 MHz)


• Arbitrary waveforms: 16,300-point record length, 12-bit resolution, 40 MSa/s update rate (25 ns minimum) Output Characteristics


• Amplitude: 10 mVpp to 10 Vpp into 50 Ω; 20 Vpp Hi-Z; 3-digit resolution


• Display units: Vp, Vpp, Vrms, dBm


• Output impedance: 50 Ω; floating to ±40 V relative to earth ground


• Square wave rise/fall time: <15 ns (10%–90% at full output)


• TTL and ECL outputs available Modulation & Sweeps


• AM (0–100%, 1% resolution; DSBSC supported); FM, PM (±7199.999°); burst with configurable count and starting point


• Modulation rate: 1 mHz to 10 kHz


• External AM input: ±5 V for 100% modulation, 100 kΩ impedance, 15 kHz bandwidth


• Frequency sweeps: linear or logarithmic, phase-continuous, up/down/up-down/single modes

Key Features

• Adjustable DC offset on all outputs


• Modulation waveform sources: sine, square, triangle, ramp, arbitrary


• Dual independent outputs (TTL, ECL)


• Phase-locked frequency control

Typical Applications

• Frequency response and impedance measurements


• Analog filter characterization and validation


• RF/IF circuit development and testing


• Audio and instrumentation signal simulation

Compatibility & Integration The DS345 operates as a standalone instrument with TTL/ECL trigger and output interfaces. External modulation input accepts ±5 V signals at 100 kΩ impedance.