Function Generator

DS345 Function/Arb Generator

The DS345 Function Generator is a full-featured 30 MHz synthesized function generator that uses an innovative Direct Digital Synthesis (DDS) architecture. It generates many standard waveforms with excellent frequency resolution (1 µHz), and has versatile modulation capabilities including AM, FM, Burst, PM and frequency sweeps. It also generates arbitrary waveforms with a fast 40 Msample/s update rate.

Functions and Outputs

The DS345 generates sine waves and square waves at frequencies up to 30.2 MHz, and triangle and ramp waveforms up to 100 kHz. The frequency resolution for all functions is 1 µHz. In addition to the standard waveforms, the unit also provides a wideband (10 MHz) white noise source.

Both the function output and a TTL SYNC output are available through floating, front-panel BNC connectors. Both outputs have 50 Ω output impedances and may be floated up to ±40 V relative to earth ground. The amplitude of all function outputs is adjustable from 10 mVpp to 10 Vpp with 3-digit resolution, and can be displayed in Vp, Vpp, Vrms or dBm. In addition, standard TTL and ECL output levels can be selected.

Additional useful connectors are provided on the rear panel. A trigger input is used to trigger arbitrary waveforms, modulation patterns, sweeps and bursts, while a TTL trigger output is provided to allow synchronization of external devices to sweeps and bursts. A sweep output generates a 0 V to 10 V ramp synchronous with frequency sweeps. The sweep marker outputs allow specified portions of a frequency sweep to be highlighted on an oscilloscope.

A 10 MHz rear-panel input allows the DS345 to be synchronized to an external timebase. A 10 MHz rear-panel output allows multiple DS345's to be phase locked.

Amplitude Modulation

Modulation

The DS345 Function Generator offers a wide variety of modulation options. It contains an internal modulation generator which can modulate any of its standard waveforms except noise. The modulation waveform can be a sine, square, triangle, ramp or an arbitrary waveform. Modulation rates from 1 mHz to 10 kHz can be selected.

The modulation generator can provide amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). When using AM, modulation depths of ±100 % can be selected with 1 % resolution. Negative values of modulation correspond to Double Sideband Suppressed Carrier (DSBSC) modulation. FM spans can be selected with 1 µHz resolution, and phase modulation can be set between 0° and 7200° with 0.001° resolution.

External Amplitude Modulation

In addition to the internal modulation generator, the output waveform can be amplitude modulated by an external signal applied to the rear-panel AM input. This input is always active—even when other modulation types are turned on.

Burst Mode

Burst Modulation

You can generate tone bursts of any output function except noise. In burst mode, the DS345 will output an exact number of complete waveform cycles after receiving a trigger. By adjusting the phase, you can control where in the waveform the burst begins. While using the burst mode, the maximum frequency for sine waves and square waves is 1 MHz, while triangles and ramps are limited to 100 kHz. Burst mode may be used with arbitrary waveforms at any frequency.

Frequency Sweeps

The DS345 Function Generator can frequency sweep any of its function outputs (except noise). You can sweep up or down in frequency using linear or log sweeps. Unlike conventional function generators, there are no annoying discontinuities or band-switching artifacts when sweeping through certain frequencies. The DS345's DDS architecture inherently allows it to perform smooth, phase-continuous sweeps over it's entire frequency range.

Frequency Modulation

Two sweep marker frequencies can be specified. When the sweep crosses either of the marker frequencies, a TTL transition is generated at the rear-panel MARKER output to allow synchronization of external devices.

Arbitrary Waveforms

The DS345 isn't just a function generator. It's also a full-featured arbitrary waveform generator. Output waveforms have 12-bit vertical resolution, and can be played back at rates up to 40 Msamples/s.

Since composing complex arbitrary waveforms at the keyboard can be a tedious task, Arbitrary Waveform Composer (AWC) software is provided at no charge. AWC is a menu-based program which lets you create and edit arbitrary waveforms on the screen, store them, and download them to the DS345. Click here for the latest version of the Windows AWC software.

DS345 Specifications
Frequency Range & Resolution
Frequency Range	Max. Frequency	Resolution
Sine	30.2 MHz	1 µHz
Square	30.2 MHz	1 µHz
Ramp	100 kHz	1 µHz
Triangle	100 kHz	1 µHz
Noise	10 MHz	(Gaussian weighting)
Arbitrary	10 MHz	40 MHz/N (sample rate)

Output
Source impedance	50 Ω
Grounding	Output may float up to ±40 V (AC + DC) relative to earth ground.
Amplitude
Range	0.01 to 10 Vpp (50 Ω), 20 Vpp (Hi-Z)
Resolution	3 digits (DC offset: 0 V)
Sine wave accuracy	(0 V DC offset)
5 to 10 Vpp	±0.2 dB (1 µHz to 20 MHz) ±0.5 dB (20 MHz to 30.2 MHz)
0.01 to 5 Vpp	±0.4 dB(1 µHz to 20 MHz) ±0.5 dB (20 MHz to 30.2 MHz)
Square wave accuracy
5 to 10 Vpp	±3 % (1 µHz to 100 kHz) ±6 % (100 kHz to 20 MHz) ±15 % (20 MHz to 30.2 MHz)
0.01 to 5 Vpp	±5 % (1 µHz to 100 kHz) ±8 % (100 kHz to 20 MHz) ±18 % (20 MHz to 30.2 MHz)
Triangle, ramp, ARB accuracy	±3 % (>5 Vpp) ±5 % (<5 Vpp)
DC Offset
Range	±5 V (\|VAC peak\| + \|VDC\| < 5 V)
Resolution	3 digits (VAC = 0)
Accuracy	1.5 % of setting + 0.2 mV (DC only) ±0.8 mV to ±80 mV, depending on AC and DC settings
Sine Wave
Spurious	-45 dBc (non-harmonic, typ.)
Phase noise	-55 dBc in a 30 kHz band centered on the carrier, exclusive of discrete spurious signals (typ.)
Sub-harmonic	<-50 dBc
Harmonic distortion	Level Freq. Range <-55 dBc DC to 100 kHz <-45 dBc 0.1 to 1 MHz <-35 dBc 1 to 10 MHz <-25 dBc 10 to 30 MHz
Square Wave
Rise/fall time	<15 ns (10 to 90 %), at full output
Asymmetry	<1 % of period + 4 ns
Overshoot	<5 % of peak to peak amplitude at full output
Ramp, Triangle and ARB
Rise/fall time	45 ns (10 MHz Bessel filter)
Linearity	±0.5 % of full-scale output
Settling time	<1 µs to settle within 0.1 % of final value at full output
Arbitrary Waveforms
Sample rate	40 MHz/N, N = 1 to 2³⁴-1
Memory length	8 to 16,300 points
Resolution	12 bits (0.025 % of full scale)
Phase
Range	±7199.999° with respect to arbitrary starting phase
Resolution	0.001°

Amplitude Modulation
Source	Internal (sine, square, triangle or ramp) or External
Depth	0 to 100 % AM or DSBSC
Rate	0.001 Hz to 10 kHz internal, 15 kHz max. external
Distortion	<-35 dB at 1 kHz, 80 % depth
DSB carrier	<-35 dB typ. at 1 kHz modulation rate (DSBSC)
External input	±5 V for 100 % modulation, 100 kΩ impedance, 15 kHz bandwidth
Frequency Modulation
Source	Internal (sine, square, triangle, ramp or arbitrary)
Rate	0.001 Hz to 10 kHz
Span	1 mHz to 30.2 MHz (100 kHz for triangle, ramp)
Phase Modulation
Source	Internal (sine, square, triangle, ramp)
Rate	0.001 Hz to 10 kHz
Span	±7199.999°
Frequency Sweep
Type	Linear or log, phase continuous
Waveform	Up, down, up-down, single sweep
Time	0.001 s to 1000 s
Span	1 mHz to 30.2 MHz (to 100 kHz for triangle, ramp)
Markers	Two markers may be set at any sweep point (TTL output)
Sweep output	0 to 10 V linear ramp signal, synchronized to sweep
Burst Modulation
Waveform	Any waveform except noise may be burst modulated
Frequency	Sine, square to 1 MHz Triangle, ramp to 100 kHz Arbitrary to 40 MHz sample rate
Count	1 to 30,000 cycles/burst (1 µs to 500 s burst time limits)
Trigger Generator
Source	Single, Internal, External, Line
Rate (internal)	0.001 Hz to 10 kHz (2-digit resolution)
External trigger	Positive or negative edge, TTL
Output	TTL level
Standard Timebase
Accuracy	±5 ppm (20 °C to 30 °C)
Aging	5 ppm/year
Input	10 MHz/N ± 2 ppm (N = 1 to 8) 1 Vpp minimum input level
Output	10 MHz, >1 Vpp sine into 50 Ω
Optional Timebase
Type	Ovenized AT-cut oscillator
Stability	<0.01 ppm, 20 °C to 60 °C
Aging	<0.001 ppm/day
Allan variance (1 s)	<5 × 10^-11
General
Interfaces	Optional RS-232 (300 to 19.2 kbaud, DCE) and GPIB with DOS based arbitrary waveform software (AWC). All instrument functions are controllable over the interfaces.
Non-volatile memory	Nine sets of instrument settings can be saved and recalled
Dimensions	8.5" × 3.5" × 13" (WHL)
Weight	10 lbs.
Power	50 W, 100/120/220/240 VAC, 50/60 Hz
Warranty	One year parts and labor on defects in materials and workmanship

DS345 Specifications
Frequency Range & Resolution
Freq. Range	Max. Frequency	Resolution
Sine	30.2 MHz	1 µHz
Square	30.2 MHz	1 µHz
Ramp	100 kHz	1 µHz
Triangle	100 kHz	1 µHz
Noise	10 MHz	(Gaussian weighting)
Arbitrary	10 MHz	40 MHz/N (sample rate)

Output
Source impedance	50 Ω
Grounding	Output may float up to ±40 V (AC + DC) relative to earth ground.
Amplitude
Range	0.01 to 10 Vpp (50 Ω), 20 Vpp (Hi-Z)
Resolution	3 digits (DC offset: 0 V)
Sine wave accuracy	(0 V DC offset)
5 to 10 Vpp	±0.2 dB (1 µHz to 20 MHz) ±0.5 dB (20 MHz to 30.2 MHz)
0.01 to 5 Vpp	±0.4 dB(1 µHz to 20 MHz) ±0.5 dB (20 MHz to 30.2 MHz)
Square wave accuracy
5 to 10 Vpp	±3 % (1 µHz to 100 kHz) ±6 % (100 kHz to 20 MHz) ±15 % (20 MHz to 30.2 MHz)
0.01 to 5 Vpp	±5 % (1 µHz to 100 kHz) ±8 % (100 kHz to 20 MHz) ±18 % (20 MHz to 30.2 MHz)
Triangle, ramp, ARB accuracy	±3 % (>5 Vpp) ±5 % (<5 Vpp)
DC Offset
Range	±5 V (limited such that \|VAC peak\| + \|VDC\| < 5 V)
Resolution	3 digits (VAC = 0)
Accuracy	1.5 % of setting + 0.2 mV (DC only) ±0.8 mV to ±80 mV, depending on AC and DC settings
Sine Wave
Spurious	-45 dBc (non-harmonic, typ.)
Phase noise	-55 dBc in a 30 kHz band centered on the carrier, exclusive of discrete spurious signals (typ.)
Sub-harmonic	<-50 dBc
Harmonic distortion	Level Freq. Range <-55 dBc DC to 100 kHz <-45 dBc 0.1 to 1 MHz <-35 dBc 1 to 10 MHz <-25 dBc 10 to 30 MHz
Square Wave
Rise/fall time	<15 ns (10 to 90 %), at full output
Asymmetry	<1 % of period + 4 ns
Overshoot	<5 % of peak to peak amplitude at full output
Ramp, Triangle and ARB
Rise/fall time	45 ns (10 MHz Bessel filter)
Linearity	±0.5 % of full-scale output
Settling time	<1 µs to settle within 0.1 % of final value at full output
Arbitrary Waveforms
Sample rate	40 MHz/N, N = 1 to 2³⁴-1
Memory length	8 to 16,300 points
Resolution	12 bits (0.025 % of full scale)
Phase
Range	±7199.999° with respect to arbitrary starting phase
Resolution	0.001°
Amplitude Modulation
Source	Internal (sine, square, triangle or ramp) or External
Depth	0 to 100 % AM or DSBSC
Rate	0.001 Hz to 10 kHz internal, 15 kHz max. external
Distortion	<-35 dB at 1 kHz, 80 % depth
DSB carrier	<-35 dB typ. at 1 kHz modulation rate (DSBSC)
External input	±5 V for 100 % modulation, 100 kΩ impedance, 15 kHz bandwidth
Frequency Modulation
Source	Internal (sine, square, triangle, ramp or arbitrary)
Rate	0.001 Hz to 10 kHz
Span	1 mHz to 30.2 MHz (100 kHz for triangle, ramp)
Phase Modulation
Source	Internal (sine, square, triangle, ramp)
Rate	0.001 Hz to 10 kHz
Span	±7199.999°
Frequency Sweep
Type	Linear or log, phase continuous
Waveform	Up, down, up-down, single sweep
Time	0.001 s to 1000 s
Span	1 mHz to 30.2 MHz (to 100 kHz for triangle, ramp)
Markers	Two markers may be set at any sweep point (TTL output)
Sweep output	0 to 10 V linear ramp signal, synchronized to sweep
Burst Modulation
Waveform	Any waveform except noise may be burst modulated
Frequency	Sine, square to 1 MHz Triangle, ramp to 100 kHz Arbitrary to 40 MHz sample rate
Count	1 to 30,000 cycles/burst (1 µs to 500 s burst time limits)
Trigger Generator
Source	Single, Internal, External, Line
Rate (internal)	0.001 Hz to 10 kHz (2-digit resolution)
External trigger	Positive or negative edge, TTL
Output	TTL level
Standard Timebase
Accuracy	±5 ppm (20 °C to 30 °C)
Aging	5 ppm/year
Input	10 MHz/N ± 2 ppm (N = 1 to 8) 1 Vpp minimum input level
Output	10 MHz, >1 Vpp sine into 50 Ω
Optional Timebase
Type	Ovenized AT-cut oscillator
Stability	<0.01 ppm, 20 °C to 60 °C
Aging	<0.001 ppm/day
Allan variance (1 s)	<5 × 10^-11
General
Interfaces	Optional RS-232 (300 to 19.2 kbaud, DCE) and GPIB with DOS based arbitrary waveform software (AWC). All instrument functions are controllable over the interfaces.
Non-volatile memory	Nine sets of instrument settings can be saved and recalled
Dimensions	8.5" × 3.5" × 13" (WHL)
Weight	10 lbs.
Power	50 W, 100/120/220/240 VAC, 50/60 Hz
Warranty	One year parts and labor on defects in materials and workmanship