DS335

The Stanford Research Systems DS335 is a 3.1 MHz synthesized function generator that utilizes direct digital synthesis (DDS) to provide high-resolution, phase-continuous waveforms. It generates sine, square, triangle, and ramp waves, alongside a 10 MHz white noise source, with a frequency resolution of 1 µHz. The DS335 also includes linear and logarithmic frequency sweeps, binary FSK modulation, and optional GPIB and RS-232 digital interfaces for computer control.

Function Generation Signal Generation

Specifications

General

Parameter	Value
Interfaces	GPIB and RS-232 (with Option 01)
Display	12-digit green LED
Setup Storage	9 instrument configurations

Physical

Parameter	Value
Power Supply	100/120/220/240 VAC, 50/60 Hz, 22 W
Operating Temperature	0°C to 50°C
Dimensions (W×H×D)	216 mm × 89 mm × 330 mm
Weight	3.6 kg

Waveform Characteristics

Parameter	Value
Standard Waveforms	Sine, Square, Triangle, Ramp, Noise

Frequency Specifications

Parameter	Value
Sine Frequency Range	1 µHz to 3.1 MHz
Square Frequency Range	1 µHz to 3.1 MHz
Triangle Frequency Range	1 µHz to 10 kHz
Ramp Frequency Range	1 µHz to 10 kHz
Noise Bandwidth	10 MHz
Frequency Resolution	1 µHz
Frequency Accuracy	±5 ppm (0°C to 50°C)
Aging Rate	< 5 ppm/year

Amplitude & Output Characteristics

Parameter	Value
Amplitude Range (50 Ω)	50 mVpp to 10 Vpp
Amplitude Range (Open Circuit)	100 mVpp to 20 Vpp
Amplitude Resolution	3 digits
Amplitude Accuracy (at 1 kHz)	±0.1 dB (1.15%) of setting for amplitudes > 0.1 Vpp
Sine Flatness (100 Hz to 1 MHz)	±0.15 dB
Sine Flatness (1 MHz to 3.1 MHz)	±0.3 dB
Output Impedance	50 Ω
DC Offset Range (50 Ω)	±5 VDC
DC Offset Range (Open Circuit)	±10 VDC
Output Protection	Short-circuit protected

Sine Wave Distortion & Purity

Parameter	Value
Harmonic Distortion (DC to 20 kHz)	<-55 dBc
Harmonic Distortion (20 kHz to 100 kHz)	<-50 dBc
Harmonic Distortion (100 kHz to 1 MHz)	<-40 dBc
Harmonic Distortion (1 MHz to 3.1 MHz)	<-35 dBc
Spurious Noise (<100 kHz)	<-55 dBc (DC to 1 MHz)
Phase Noise	<-50 dBc in a 30 kHz band centered on the carrier

Square Wave Characteristics

Parameter	Value
Square Wave Rise/Fall Time	<15 ns (10% to 90% at full output)
Square Wave Overshoot	<5% (at full output)
Square Wave Symmetry	50% ± 1%

Ramp Characteristics

Parameter	Value
Ramp Symmetry Range	0% to 100%
Ramp Symmetry Resolution	1%
Ramp Linearity	<0.1% of full scale

Noise Characteristics

Parameter	Value
Noise Type	Pseudo-random White Noise
Noise Flatness (DC to 100 kHz)	<±1.0 dB
Noise Flatness (100 kHz to 1 MHz)	<±2.0 dB
Noise Flatness (1 MHz to 10 MHz)	<±3.0 dB

Sweep & Modulation

Parameter	Value
Sweep Type	Linear or Logarithmic
Sweep Rate	0.01 Hz to 1 kHz
Sweep Time Range	1 ms to 100 s
Sweep Span	1 µHz to 3.1 MHz
Sweep Phase	Phase continuous
Modulation Type	Binary FSK (Frequency Shift Keying)
FSK Rate (Internal)	0.01 Hz to 50 kHz
FSK Rate (External)	DC to 1 MHz (TTL input)

Inputs & Outputs

Parameter	Value
Main Output Connector	Front-panel BNC
Sync Output	Front-panel BNC, TTL level
Trigger Input	Rear-panel BNC, TTL level
FSK Input	Rear-panel BNC, TTL level
External Clock Input Frequency	10 MHz
Clock Output Frequency	10 MHz
Clock Output Level	TTL (into 50 Ω)
FSK/Trig Input Impedance	>10 kΩ

Clock & Synchronization

Parameter	Value
External Clock Input	Rear-panel BNC, 10 MHz, -2 dBm to +15 dBm
Clock Output	Rear-panel BNC, 10 MHz, TTL level into 50 Ω

Physical & Environmental

Parameter	Value
Operating Humidity Range	Up to 95% non-condensing

Connectivity

Parameter	Value
Standard Interfaces Option	Option 01 adds GPIB (IEEE-488) and RS-232

Timebase

Parameter	Value
Standard Timebase Stability	±5 ppm (0 °C to 50 °C)
Option 01 TCXO Frequency Stability	±1 ppm (0 °C to 50 °C)
Option 01 TCXO Aging Rate	±1 ppm/year
Standard Timebase Frequency	10 MHz

Phase

Parameter	Value
Phase Range	-360° to +360°
Phase Resolution	0.001°

Sine Wave Performance

Parameter	Value
Spurious Components (DC to 1 MHz)	<-50 dBc
Spurious Components (1 MHz to 3.1 MHz)	<-40 dBc

DC Offset

Parameter	Value
DC Offset Resolution	3 digits

Power

Parameter	Value
Power Consumption	35 W

Auxiliary Inputs & Outputs

Parameter	Value
Sync Output Level	TTL

Technology

Direct Digital Synthesis (DDS)

Applications

Electronic testing, signal modulation, and waveform generation