Name: Model 686 Arbitrary Waveform Generator
Brand: Berkeley Nucleonics

1Overview

The Berkeley Nucleonics Model 686 is the fastest 14-bit arbitrary waveform generator in the line. A programmable sample rate from 1 Sa/s to 20 GS/s, 14-bit vertical resolution, and up to 9 Gpts of waveform memory let a single instrument reproduce nearly any signal, ideal or distorted, standard or fully custom. Two or four analog channels are available, each capable of 5 Vpp single-ended or 1.25 Vpp differential into 50 ohm, with rise and fall times as short as 50 ps and a 6.5 GHz sine output. The instrument reaches 10 GHz of generation bandwidth, so the real-world edges and pulse shapes demanded by frontier test cases come straight off the front panel.

The 686 was built for mixed-signal work. Four-channel models add up to 32 synchronized digital channels through an optional license, so analog stimulus and digital patterns run together for debugging and validating high-speed digital designs. When one chassis is not enough, up to four instruments synchronize over a dedicated bus to form a single 16 analog and 128 digital channel generator, with intra-chassis timing held tight across the group.

Operation is organized around three software modes that share one touch-driven platform. Simple Rider AFG provides a DDS function-generator interface for fast, conventional waveform setup. TrueArb is a variable-clock arbitrary mode for long, sequenced waveforms with loops, jumps, and conditional branches. The optional Pulse Pattern Generator (PPG) produces PRBS and custom serial patterns up to 6.5 Gbaud with arbitrarily shaped bit transitions. A 7-inch capacitive touchscreen, front-panel buttons, and a control knob handle local operation, while LAN, USB-TMC, and GPIB cover remote control and automation.

Berkeley Nucleonics Model 686 arbitrary waveform generator, three-quarter view — Model 686, three-quarter view showing the 7-inch touchscreen, control knob, and front-panel SMA output bank.

2Key Features

Up to 20 GS/s, 14-bit. Sample rate programmable from 1 Sa/s to 20 GS/s with 14-bit vertical resolution for exceptional signal integrity.
Deep memory. Arbitrary waveform memory up to 9 Gpts for long, complex playback without re-loading.
Mixed-signal generation. 2 or 4 analog channels with up to 32 synchronized digital channels for debugging and validating digital designs.
Three operation modes. Simple Rider AFG (DDS function generator), TrueArb (variable-clock arbitrary AWG), and PPG (pulse and serial pattern generator, optional).
High-rate digital outputs. Up to 10 Gb/s per channel in programmable CML; a CML-to-LVTTL adapter is available.
Advanced sequencer. Up to 16,384 user-defined waveform entries build complex signal scenarios with efficient memory use.
Fast edges, high amplitude. 5 Vpp output with rise and fall times to 50 ps and 6.5 GHz sine, a strong amplitude-and-bandwidth combination.
Synchronization to 16 / 128 channels. Up to four units lock together for 16 analog and 128 digital channels over a dedicated sync bus.
Windows platform. 7-inch capacitive touchscreen, front-panel buttons and knob, Windows 10, and a compact 3U 19-inch rackmount form factor.
Standard remote interfaces. LAN, USB-TMC, and GPIB for instrument control and automated programming.

3Front & Rear Panels

The front panel groups the touchscreen, control knob, and numeric keypad on the left, with the analog output bank, marker outputs, and trigger inputs on the right. The rear panel carries the reference and sync clock connectors, the digital output pods, the QSFP synchronization links, the computing ports, and AC input.

Model 686 front panel: 7-inch touchscreen and knob, AFG keypad, CH OUT SMA bank, marker outputs, and trigger inputs.

Model 686 rear panel: reference and sync clock SMA connectors, sync I/O, computing ports, digital output pods, and AC inlet.

4Software Modes

The 686 presents one touch-driven platform with three operating interfaces. Each is purpose-built for a class of signal generation, and all share the same instrument hardware.

Simple Rider AFG: Function Generator Mode

The AFG interface puts the capabilities of a modern function generator at the user's fingertips, with a tablet-style touch layout. A swipe gesture exposes the output waveform parameters, a touch-friendly numeric keypad speeds data entry, and shortcuts and intuitive icons streamline setup. Standard waveforms include sine, square, pulse, ramp, noise, DC, Sin(x)/x, Gaussian, Lorentz, exponential rise, exponential decay, and Haversine.

Simple Rider AFG function generator interface — Simple Rider AFG: function-generator mode with carrier waveform, amplitude, frequency, phase, and run-mode controls.

Simple Rider TrueArb: AWG Mode

TrueArb lets users define complex waveforms with up to 16,384 sequence entries of analog waveforms and digital patterns, and lay out execution flow with loops, jumps, and conditional branches. Waveform memory of up to 9 GSamples per channel, combined with sequence repeats up to 4,294,967,294, makes the 686 suited to the most demanding scenarios. Synchronized digital output paired with the analog signals provides an effective tool for troubleshooting and validating digital designs.

TrueArb analog sequencer interface — TrueArb analog sequencer: per-entry waveform selection (sine, DC, ramp, Gaussian) with repetition and length control.

TrueArb digital pattern sequencer interface — TrueArb digital sequencer: synchronized digital pattern entries shown alongside the analog timeline.

Simple Rider PPG: Pulse Pattern Generator Mode

The optional PPG interface creates pattern scenarios in a few screen touches. It generates PRBS patterns and custom patterns up to 12 MSymbols, where bit transitions can take arbitrarily user-defined shapes, at rates up to 6.5 Gbaud. The architecture supports several generation modes and can modulate patterns with internal or external signals to introduce controlled impairments such as jitter and ripple.

Simple Rider PPG pulse pattern generator interface — Simple Rider PPG: pattern carrier and transition data with programmable rise and fall times and run mode.

5General Specifications

All specifications are typical unless noted otherwise. Guaranteed performance refers to a calibrated instrument stored for at least 2 hours within the operating temperature range of 41 to 104 F (5 to 40 C), after a 45-minute warm-up, and within 18 F (10 C) of the auto-calibration temperature.

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Operating modes	AFG mode, TrueArb mode, SPG / PPG mode (optional)
Analog channels	2 (2-channel models) or 4 (4-channel models)
Markers	2 (2-channel models) or 4 (4-channel models)
Digital channels	Up to 32 (4-channel models, optional license)
Output type	Single-ended, DC coupled	Differential, DC coupled
Output impedance	50 ohm single-ended	50 ohm single-ended / 100 ohm differential
Connectors	SMA on front panel
Vertical resolution	14-bit

DC Amplitude

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Amplitude range	±2.5 V (into 50 ohm)	±0.625 V SE (into 50 ohm); ±1.25 V diff. (into 100 ohm)
Resolution	500 µV nom, 5 digits	100 µV nom, 5 digits
Amplitude accuracy	±(1.5% of \|setting\| + 15 mV)	±(1% of \|setting\| + 2 mV)

DC Baseline Hardware Offset (Common-Mode Offset)

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Resolution	Less than 4 mV or 4 digits
Range (50 ohm into 50 ohm)	-2.5 V to +2.5 V	-2 V to +2 V
Range (50 ohm into high-Z load)	-2.5 V to +2.5 V	-4 V to +4 V
Accuracy (50 ohm into 50 ohm), guaranteed	±(1% of \|setting\| + 15 mV)	±(1% of \|setting\| + 5 mV)
AC accuracy (1 kHz sine, 0 V offset, >5 mVpp, 50 ohm), guaranteed	±(1% of setting [Vpp] + 5 mV)

Amplitude and AC accuracy specifications are guaranteed across 0% to 80% of full-scale output.

6TrueArb (Baseband) Specifications

Parameter	Specification
Operating modes	Full Rate mode (variable clock), Half Rate mode (variable clock)
Sampling rate, Full Rate	1 Sa/s to 20 GS/s
Sampling rate, Half Rate	1 Sa/s to 10 GS/s
Sin(x)/x corner	8.85 GHz at 20 GS/s (686-2CD / 686-4CD)
Run modes	Continuous, triggered continuous, single/burst, stepped, advanced
Vertical resolution	14-bit
Max waveform memory, Full Rate, 2-channel	CH1: 9.6 Gsamples; CH2: 1.17 Msamples
Max waveform memory, Full Rate, 4-channel	CH1, CH3: 9.6 Gsamples; CH2, CH4: 589 ksamples
Waveform granularity	1 if entry length > 8928 samples; 288 if entry length 288 to 8928 samples
Sequence length	1 to 16,384
Sequence repeat counter	1 to 4,294,967,294 or infinite
Timer range	17.6 ns to 429 ms
Timer resolution	±1 sampling clock cycle

Analog Channel-to-Channel Skew

Parameter	Specification
Range	0 to 1.63 µs
Resolution, 4-channel	CHx to CHx (x=1,2,3,4): 1 sampling clock cycle; CH1/CH2 to CH3/CH4: 100 fs
Resolution, 2-channel	CHx to CHx (x=1,2): 100 fs
Accuracy	±(1% of setting + 20 ps)
Initial skew	Less than 20 ps

Bandwidth, SFDR, and Edges

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Calculated bandwidth (0.35 / rise or fall, 10-90)	≥ 5 GHz	≥ 5.8 GHz
Measured 3 dB bandwidth (Sin(x)/x compensated)	5.8 GHz
SFDR at 100 MHz (Fs = 20 GS/s)	Less than -65 dBc
SFDR, 18 mHz to 100 MHz (Fs = 20 GS/s)	Less than -65 dBc
Rise/fall time (1 Vpp SE, 20% to 80%)	≤ 50 ps	≤ 45 ps
Rise/fall time (1 Vpp SE, 10% to 90%)	≤ 70 ps	≤ 60 ps
Overshoot (1 Vpp SE)	Less than 8%	Less than 6%
Random jitter on clock pattern	Less than 2 ps

SFDR is measured across DC to Fs/2, excluding Fs − 2·fout, Fs − 3·fout, and harmonics.

Model 686 waveform memory per channel in Full Rate mode — Waveform memory per channel in Full Rate mode (20 GS/s): CH1 and CH3 reach 9.6 Gsamples; secondary channels carry shorter playback memory.

7AFG Mode Specifications

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Amplitude range	0 to 5 Vpp (into 50 ohm)	0 to 2.5 Vpp diff. (into 100 ohm); 0 to 1.25 Vpp SE (into 50 ohm)
Resolution	500 µV nom, 5 digits	100 µV nom, 5 digits
Operating mode	DDS mode
Standard waveforms	Sine, square, pulse, ramp, noise, DC, Sin(x)/x, Gaussian, Lorentz, exponential rise, exponential decay, Haversine
Run modes	Continuous, modulation, sweep, burst
Arbitrary mode	14-bit vertical resolution; waveform length 16,384 points

Internal Trigger Timer

Parameter	Specification
Range	6.5 ns to 100 s
Resolution	31.25 ps
Accuracy	±(0.1% setting + 5 ps)

Sine Waves

Parameter	686-2C-SE / 686-4C-SE	686-2CD / 686-4CD
Max frequency	6.5 GHz
Frequency range vs. amplitude	18 mHz to 3.5 GHz: 5 Vpp; 3.5 to 4.5 GHz: 4 Vpp; 4.5 to 6.5 GHz: 3 Vpp	18 mHz to 6.5 GHz: 2.5 Vpp diff.; 18 mHz to 6.5 GHz: 1.25 Vpp SE
Flatness	DC to 6 GHz: ±0.5 dB (1 Vpp, ref. 1 kHz)	DC to 6.5 GHz: ±0.5 dB (1 Vpp diff., ref. 1 kHz)
Harmonic distortion (1 Vpp)	18 mHz to 1 MHz: < -60 dBc; 1 MHz to 1 GHz: < -50 dBc; 1 GHz to 6.5 GHz: < -40 dBc
Total harmonic distortion (1 Vpp)	10 Hz to 20 kHz: < 0.2%
Spurious (18 mHz to 1 MHz, Fs = 20 GS/s)	Less than -60 dBc
Phase noise (1 Vpp, 10 kHz offset)	20 MHz: < -127 dBc/Hz typ.; 100 MHz: < -124 dBc/Hz typ.; 1 GHz: < -105 dBc/Hz typ.

For single-ended models, spurious are evaluated at 1 Vpp single-ended nominal output amplitude.

Square, Pulse, and Double-Pulse Waves

Parameter	Specification
Square frequency range	18 mHz to 2.5 GHz (all channels)
Square rise/fall (10% to 90%)	120 ps
Square rise/fall (20% to 80%)	90 ps
Square overshoot / jitter (1 Vpp)	Less than 2% / less than 2 ps rms
Pulse frequency range	18 mHz to 2.5 GHz
Pulse width	150 ps to (Period − 150 ps)
Pulse width resolution	20 ps or 15 digits
Pulse duty	0.1% to 99.9% (pulse-width limits apply)
Leading/trailing edge transition (10% to 90%)	120 ps to 1000 s
Transition time resolution	2 ps or 15 digits
Double-pulse range (Vpp = \|Vpp1\| + \|Vpp2\|)	18 mHz to 1.25 GHz: 10 Vpp; 5 Vpp diff.; 2.5 Vpp SE

Below 150 ps width, the pulse amplitude reduces somewhat relative to the set value.

Ramp, Other Waves, and Noise

Parameter	Specification
Ramp frequency range	18 mHz to 250 MHz
Ramp linearity (< 10 kHz, 1 Vpp, 100%)	≤ 0.1%
Ramp symmetry	0% to 100%
Exponential rise / decay range	18 mHz to 250 MHz
Sin(x)/x, Gaussian, Lorentz, Haversine range	18 mHz to 500 MHz
Additive noise bandwidth (-3 dB)	4 GHz
Additive noise level	0 V to 2.5 V − \|carrier max [Vpk]\| (SE: to 0.625 V; diff.: to 1.25 V)
Arbitrary samples / frequency range	2 to 16,384 / 1 µHz to 2.5 GHz
Arbitrary analog bandwidth (-3 dB)	2.9 GHz
Frequency accuracy (non-ARB)	±2.0 ppm of setting; ±500 ppb of setting (opt.)

Modulation and Sweep

Parameter	Specification
Modulation types	AM, FM, PM, FSK, PSK, PWM
Modulation source	Internal or external
Internal modulating frequency	18 mHz to 80 MHz (external: 1 GHz max.)
AM depth	0.00% to 120.00%
FM peak deviation	DC to 6.5 GHz
PM phase deviation	0° to 360°
FSK hop frequency	1 µHz to 6.5 GHz
Sweep types	Linear, logarithmic, staircase, user defined
Sweep time	4 ns ≤ rise + hold + fall ≤ 2000 s
Total sweep time accuracy	≤ 0.4%
Burst count	1 to 4,294,967,295 cycles or infinite

8Pulse Pattern Generator (PPG) Specifications — Optional

Parameter	Specification
Operating mode	NRZ, RZ, or R1 bitstream pattern generator
Pattern types	Clock, custom, PRBS, Go-Through, pulse
Run modes	Continuous, modulation, burst (triggered, gated, continuous triggered)
Internal trigger timer	6.5 ns to 100 s, 31.25 ps resolution, ±(0.1% setting + 5 ps)
Transition shapes	Arbitrary or predefined (sine, square, pulse, ramp up/down, DC, Sin(x)/x, Gaussian, Lorentz, exp. rise/decay, Haversine)
Transitions memory length	64 points
Transition duration	150 ps to symbol duration (custom, PRBS, Go-Through)

Pattern Types

Pattern	Specification
Clock pattern	Max 3.25 GHz, 2 levels, overshoot < 2%, jitter < 2 ps rms
Custom pattern rate	Up to 6.5 Gbaud; 2, 3, or 4 levels
Custom pattern memory	Up to 12 Mbit (2 levels) / 6 MSymbols (3 or 4 levels) on 2-channel models; up to 6 Mbit / 3 MSymbols on 4-channel models
Custom pattern length	Min 16 bits, 1-bit resolution
PRBS pattern rate / types	Up to 6.5 Gbaud; PRBS-7, 9, 11, 15, 23, 31; 2 levels
Go-Through pattern rate	Up to 6.5 Gbaud; 2, 3, or 4 levels; max external pattern rate 1 Gbit/s
Pulse pattern	Up to 3.25 GHz; min rise/fall 150 ps; min pulse width 300 ps

Pattern Modulation and Burst

Parameter	Specification
Modulation types	AM, FM, PM, FSK, PSK
Internal modulating frequency	18 mHz to 80 MHz (external: 1 GHz max.)
AM depth	0.00% to 120.00%
FSK hop symbol rate	1 µSymbol/s to 6.5 GSymbol/s (custom, PRBS); 18 mHz to 3.25 GHz (clock)
Burst type / count	Block mode or bit mode; 1 to 4,294,967,295 cycles or infinite

9Timing & Clock

Parameter	Specification
Sampling rate range	1 Sa/s to 20 GS/s
Sampling rate resolution	64 Hz
Sampling rate accuracy	±2.0 ppm; ±500 ppb (opt.)
Reference clock input	SMA rear panel, 50 ohm AC coupled, 5 MHz to 500 MHz, 0.2 to 3.3 Vpp
Reference clock output	SMA rear panel, 10 MHz TCXO (100 MHz VCOCXO optional), 1.65 Vpp
Reference initial accuracy at 77 F (25 C)	±1.0 ppm; ±500 ppb (opt.)
Reference aging	±1.0 ppm/year; ±500 ppb/year (opt.)
External clock input	SMA rear panel, 50 ohm AC coupled, +0 to +10 dBm
Sync clock output	SMA rear panel, 50 ohm AC coupled, 1 Vpp into 50 ohm

10Digital Outputs

Parameter	Specification
Connectors	Mini-SAS HD on rear panel (custom pin-out), 4 connectors
Number of outputs	32 bits
Output impedance	100 ohm differential
Output type	CML with programmable peak-to-peak amplitude
Maximum update rate	10 Gb/s per channel
Memory depth	4.5 Gbit per digital channel

Digital channels are available on 4-channel models through an optional license (8, 16, or 32 channels). The AT-DTTL8 adapter probe converts 8 bits of LVDS to LVTTL, and the AT-LVDS-SMA8 cable breaks a Mini-SAS HD pod out to SMA.

11Auxiliary Input and Output

Parameter	Specification
Sync in / out	QSFP connector on rear panel (custom pinout)
Modulation input (MOD_IN)	SMA front panel, 50 ohm, ±1 V window; 2 (2-ch) or 4 (4-ch) connectors
Marker output	SMA front panel, 50 ohm; voltage window -0.5 V to 1.65 V; amplitude 100 mVpp to 2.15 Vpp
Marker accuracy / resolution	±(5% setting + 25 mV) / 1 mV
Marker max update rate (TrueArb)	20 Gb/s; > 4 Gb/s at 1 Vpp swing
Marker rise/fall (10% to 90%, 2 Vpp)	< 150 ps
Trigger / event inputs	SMA front panel; 50 ohm or 1 kohm; 2 (2-ch) or 4 (4-ch)
Trigger input range	±3.5 V (50 ohm); ±10 V (1 kohm)
Trigger threshold control	-8 V to 8 V, 10 mV resolution, ±100 mV accuracy
Trigger minimum pulse width (1 Vpp)	1 ns
Trigger programmable delay	0 ps to 2418 ps, 78 ps resolution

12Power & System

Parameter	Specification
Source voltage and frequency	100 to 240 VAC ±10% at 45 to 66 Hz
Max power consumption	250 W
Operating temperature	41 to 104 F (5 to 40 C)
Non-operating temperature	-4 to 140 F (-20 to 60 C)
Operating humidity	5% to 80% RH, non-condensing (de-rates at upper temperature)
Operating altitude	9,842 ft (3,000 m) max at or below 77 F (25 C)
Safety	EN 61010-1
EMC	EN 61326-1:2013
Display	7-inch, 1024 x 600, capacitive touch LCD
Operating system	Windows 10
Processor / memory / storage	Intel Pentium Gold G6400 4 GHz or better / 32 GB or better / 1 TB SSD or better
External dimensions	17.5 x 5.3 x 12.6 in (445 x 135 x 320 mm), 3U 19-inch rackmount
Weight	Max 26.45 lb (12 kg)
Remote interfaces	LAN (10/100/1000BaseT, RJ45), USB-TMC, GPIB

13Ordering & Part Numbering

The base instrument is selected by channel count and output type. Single-ended models deliver 5 Vpp into 50 ohm; differential models deliver 2.5 Vpp differential, equivalent to 1.25 Vpp single-ended. Digital channels, the serial pattern generator, fast sequence switch, and synchronization are added as options.

Model 686 part numbering — Model 686 configuration and part numbering.

Available Models

Model	Description
686-2C-SE	2 channels, 5 Vpp single-ended outputs, 20 GS/s
686-2CD	2 channels, 2.5 Vpp differential (1.25 Vpp single-ended) outputs, 20 GS/s
686-4C-SE	4 channels, 5 Vpp single-ended outputs, 20 GS/s
686-4CD	4 channels, 2.5 Vpp differential (1.25 Vpp single-ended) outputs, 20 GS/s

Options

Item	Description
686-PAT	Serial Pattern Generator (SPG)
686-8DIG	8-channel digital license (4-channel models only)
686-16DIG	16-channel digital license (4-channel models only)
686-32DIG	32-channel digital license (4-channel models only)
686-FSS	Fast Sequence Switch
686-WAR	3-year warranty extension
RIDER-MINI-SAS-HD	Mini-SAS HD cable for digital probe, 8 differential signals (4-channel models only)
RIDER-686-SYNC	Synchronization cable for all 686 models
GP-IB / USB-TMC	GPIB and USB-TMC ports for remote control

Accessories

Item	Description
DTTL8 (AT-DTTL8)	8-bit LVDS to LVTTL converter probe (4-channel models only)
LVDS-SMA8 (AT-LVDS-SMA8)	Mini-SAS HD to 16 SMA cable, 8 differential bits (4-channel models only)
RIDER-RACK	Rackmount kit for the Rider instrument system

14Applications

The Model 686 pairs fast edges, high amplitude, and deep sequencing to emulate real-world signals across research, communications, and defense work.

Quantum and QKD. Pulse shaping for quantum sensing and quantum key distribution, cold-atom experiments, and manipulation of nitrogen-vacancy color centers in diamond.
Optics and photonics. Driving electro-optic and acousto-optic modulators, pulsed laser diodes, and quantum-optics emitters with narrow, high-amplitude pulses.
Radar and electronic warfare. RF, IF, and IQ waveform synthesis, modulated radar emulation, and complex EW scenario generation through the advanced sequencer.
LiDAR and automotive. Physical-layer, transmitter, receiver, and channel testing for camera, LiDAR, radar, and ultrasound sensor systems.
High-speed serial. PRBS and multi-level PAM stimulus for SATA, USB, and PCI Express compliance and debug work.
High-energy and pulsed-power timing. Signal emulation for accelerators, tokamaks, and synchrotrons, including pulsed electron-beam, X-ray source, and HEL/ICF timing applications.

Optics and photonics laser bench — Optics and photonics: driving modulators and pulsed laser sources on an optical bench.

Quantum key distribution and secure communication — Quantum sensing and quantum key distribution for secure communication.

Large-scale physics experiment — Advanced research: signal emulation for accelerators, tokamaks, and synchrotrons.

Semiconductor device under test — Semiconductor test: high-speed serial stimulus and fast-edge device characterization.

Aerospace and defense platform — Aerospace and defense: radar, LiDAR, and sonar emulation and avionics testing.

15Software & Support

The Model 686 is programmed with the 686 SDK, which exposes the instrument's modes and sequencing to custom test software. Download the 686 SDK to integrate the generator into an automated test framework over LAN, USB-TMC, or GPIB.

For a quote, configuration help, or application support, reach the Berkeley Nucleonics team.

Email: info@berkeleynucleonics.com
Phone: 800-234-7858

Need the complete document set? To request the full datasheet or the product manual, contact Berkeley Nucleonics and a specialist will follow up.