A two-channel arbitrary waveform generator delivering up to 250 MHz output, a 1.25 GS/s sample rate, and 14-bit vertical resolution in a compact, touchscreen-driven form factor. Built for circuit debugging, education, design verification, and bench-level signal generation.
Model A2255 · Datasheet rev. 1.0 · Specifications subject to verification against the published BNC datasheet
1Overview
The Berkeley Nucleonics Model A2255 is a two-channel arbitrary waveform generator built for the bench. It pairs a 1.25 GS/s sample rate with 14-bit vertical resolution and an output reach of 250 MHz, so the same instrument can produce a clean high-frequency sine, a fast-edged pulse, or a fully custom user-defined waveform up to 1 M points long. Setup and monitoring happen on an 8-inch multi-touch screen, and a high-accuracy frequency counter is integrated, so a single unit covers both generation and basic measurement at the bench.
The A2255 carries 152 built-in standard and arbitrary waveforms, a deep modulation suite spanning AM, FM, PM, PWM, FSK, PSK, ASK, BPSK and more, plus sweep and burst modes. Frequency resolution reaches 1 microhertz, and frequency accuracy holds to plus or minus 1 ppm across the operating range. USB Host, USB Device, and LAN interfaces make it straightforward to load custom waveforms and fold the unit into an automated setup.
The A2255 is a long-established model. It remains a strong, cost-effective choice for general-purpose signal generation, education, and production support. For new designs where there is a choice, Berkeley Nucleonics recommends the current high-speed models, the Model 685 and Model 686, which offer higher sample rates and wider bandwidth. Contact the BNC team to confirm the right fit for a given application.
The Model A2255 generates standard and arbitrary waveforms with 14-bit vertical resolution at sample rates up to 1.25 GS/s.
2Key Features
Two independent channels. Generate and control two outputs from a single instrument.
250 MHz output, 1.25 GS/s sample rate. High-frequency sine generation with a 1 microhertz frequency resolution.
14-bit vertical resolution. Arbitrary waveform memory up to 1 M points for detailed custom signals.
152 built-in waveforms. Standard shapes plus exponential rise and fall, sin(x)/x, step wave, and others, in addition to user-defined arbitrary waveforms.
Broad modulation suite. AM, FM, PM, PWM, FSK, 3FSK, 4FSK, PSK, OSK, ASK, BPSK, plus sweep and burst.
Low phase noise. Minus 85 dBc/Hz typical at a 10 kHz offset.
Integrated frequency counter. High-accuracy counting from 100 mHz to 200 MHz with 7-digit resolution.
8-inch multi-touch display. An 800 by 600 pixel touchscreen for direct local control.
Flexible connectivity. USB Host, USB Device, and LAN interfaces.
3Performance Specifications
Parameter
Specification
Channels
2
Frequency output
250 MHz
Sample rate
1.25 GSa/s
Vertical resolution
14 bits
Frequency resolution
1 microhertz
Frequency accuracy
Plus or minus 1 ppm, 32 to 104 F (0 to 40 C)
Arbitrary waveform length
2 points to 1 M points
Standard waveforms
Sine, square, pulse, ramp, noise, and harmonic
Arbitrary waveforms
Exponential rise, exponential fall, sin(x)/x, step wave, and others; 152 built-in waveforms total, plus user-defined arbitrary waveforms
4Frequency Range
Frequency resolution is 1 microhertz across waveform types. The upper frequency limit varies by waveform shape as listed below.
Waveform
Frequency range
Sine
1 microhertz to 250 MHz
Square
1 microhertz to 50 MHz
Pulse
1 microhertz to 25 MHz
Ramp
1 microhertz to 5 MHz
Harmonic
1 microhertz to 125 MHz
Noise
120 MHz (minus 3 dB, typical)
Arbitrary, built-in
1 microhertz to 15 MHz
Arbitrary, user-defined
1 microhertz to 50 MHz
5Amplitude & Offset
Parameter
Specification
Amplitude, into 50 ohm load
1 mVpp to 10 Vpp (at or below 40 MHz); 1 mVpp to 5 Vpp (at or below 80 MHz); 1 mVpp to 2.5 Vpp (at or below 120 MHz); 1 mVpp to 1 Vpp (at or below 250 MHz)
Amplitude, into open circuit or high-Z
2 mVpp to 20 Vpp (at or below 40 MHz); 2 mVpp to 10 Vpp (at or below 80 MHz); 2 mVpp to 5 Vpp (at or below 120 MHz); 2 mVpp to 2 Vpp (at or below 250 MHz)
Amplitude accuracy
Plus or minus (1% of |setting| + 1 mVpp), typical, 1 kHz sine, 0 V offset
Amplitude resolution
1 mV or 4 digits
Load impedance
50 ohm (typical)
DC offset range (50 ohm)
Plus or minus (5 Vpk minus Amplitude Vpp/2)
DC offset range (open circuit, high-Z)
Plus or minus (10 Vpk minus Amplitude Vpp/2)
DC offset accuracy
Plus or minus (1% of |setting| + 1 mV + Amplitude Vpp x 0.5%)
DC offset resolution
1 mV or 4 digits
6Sine Spectral Purity
Parameter
Specification
Harmonic distortion (typical, 0 dB)
DC to 1 MHz: less than minus 65 dBc; 1 MHz to 10 MHz: less than minus 60 dBc; 10 MHz to 120 MHz: less than minus 50 dBc; 120 MHz to 250 MHz: less than minus 45 dBc
Total harmonic distortion
Less than 0.05%, 10 Hz to 20 kHz, 1 Vpp
Spurious (non-harmonic, typical, 0 dB)
At or below 10 MHz: less than minus 70 dBc; above 10 MHz: less than minus 70 dBc + 6 dB/octave
Phase noise (typical, 0 dBm, 10 kHz deviation)
10 MHz: less than or equal to minus 110 dBc/Hz
7Waveform Characteristics
Square
Parameter
Specification
Rise / fall time
Less than 5 ns
Overshoot
Less than 3%
Duty cycle
50.0% (fixed)
Jitter (rms)
300 ps + 100 ppm
Pulse
Parameter
Specification
Pulse width
12 ns to 996875 s
Rise / fall time
Greater than or equal to 7 ns
Overshoot
Less than 3%
Jitter (rms)
300 ps + 100 ppm
Ramp
Parameter
Specification
Linearity
Less than or equal to 1% of peak output (typical, 1 kHz, 1 Vpp, 50% symmetry)
Symmetry
0% to 100%
Harmonic
Parameter
Specification
Harmonic order
Up to 16
Harmonic type
Even, odd, all, user
Harmonic amplitude
Settable for all harmonics
Harmonic phase
Settable
Arbitrary
Parameter
Specification
Waveform length
2 points to 1 M points
Vertical resolution
14 bits
Minimum rise / fall time
Less than 7 ns
Jitter (rms)
3 ns
8Modulation
The A2255 supports a full modulation suite: AM, FM, PM, PWM, FSK, 3FSK, 4FSK, PSK, OSK, ASK, BPSK, plus sweep and burst. Modulation may be sourced internally or externally, depending on the mode.
Amplitude Modulation (AM)
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Sine, square, ramp, noise, and arbitrary
Depth
0.0% to 100.0%
Modulation frequency
2 mHz to 100 kHz
Frequency Modulation (FM)
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Sine, square, ramp, noise, and arbitrary
Modulating frequency
2 mHz to 100 kHz
Phase Modulation (PM)
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Sine, square, ramp, noise, and arbitrary
Phase deviation
0 to 180 degrees
Modulation frequency
2 mHz to 100 kHz
Pulse-Width Modulation (PWM)
Parameter
Specification
Carrier waveform
Pulse
Source
Internal / external
Modulating waveform
Sine, square, ramp, noise, and arbitrary
Width deviation
0 to minimum of (pulse duty ratio, 100% minus pulse duty ratio)
Modulating frequency
2 mHz to 100 kHz
FSK / 3FSK / 4FSK
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Square with 50% duty cycle
Key frequency
2 mHz to 1 MHz
PSK
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Square with 50% duty cycle
Key frequency
2 mHz to 1 MHz
OSK
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal
Oscillation time
Square with 50% duty cycle
Key frequency
2 mHz to 1 MHz
ASK
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal / external
Modulating waveform
Square with 50% duty cycle
Key frequency
2 mHz to 1 MHz
BPSK
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Source
Internal
Modulating waveform
Square with 50% duty cycle
Key frequency
2 mHz to 1 MHz
9Sweep & Burst
Sweep
Parameter
Specification
Carrier waveform
Sine, square, ramp, and arbitrary (except DC)
Type
Linear and log
Sweep time
1 ms to 500 s, plus or minus 0.1%
Trigger source
Internal, external, and manual
Burst
Parameter
Specification
Carrier waveform
Sine, square, ramp, pulse, and arbitrary (except DC)
Burst count
1 to 50,000 periods, infinite, gating
Internal period
10 ns to 500 s
Gated source
External trigger
Sweep, burst, and a deep modulation suite let the A2255 stimulate circuits across a wide range of test scenarios.
10Counter & I/O
Frequency Counter
Parameter
Specification
Functions
Frequency, period, +width, -width, +duty, and -duty
Electronic circuit debugging. Stimulate and characterize circuits during development.
Education and training. A touchscreen-driven instrument well suited to the teaching lab.
Circuit testing. Verify response across a wide frequency and amplitude envelope.
Design and manufacture. Support design verification and production-floor signal generation.
Automobile maintenance and testing. Generate the signals needed for diagnostics and bench work.
From circuit debugging to design verification, the A2255 covers everyday bench signal generation.A deep modulation suite, including FSK, PSK, ASK, and BPSK, supports communications and signaling test scenarios.
12Software & Support
The Model A2255 is operated directly from its 8-inch multi-touch display, with USB Host, USB Device, and LAN interfaces for loading user-defined waveforms and connecting the unit to a host system. The integrated high-accuracy frequency counter and built-in waveform library mean most bench tasks can be handled without additional tooling.
Berkeley Nucleonics supports the A2255 with application guidance, configuration help, and service. For new designs where there is a choice, the current high-speed Model 685 and Model 686 generators are recommended, and the BNC team can help confirm which generator fits a given requirement.
Request the full datasheet. For complete specifications, ordering details, and configuration options, request the full Model A2255 datasheet through the Berkeley Nucleonics contact page.
13Contact
For a quote, configuration help, or application support, reach the Berkeley Nucleonics team.
