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.
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 at a 1 GHz carrier, 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.
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 |
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 |
10Counter & I/O
Frequency Counter
| Parameter | Specification |
|---|
| Functions | Frequency, period, +width, -width, +duty, and -duty |
| Frequency range | 100 mHz to 200 MHz |
| Frequency resolution | 7 digits |
Input / Output
| Parameter | Specification |
|---|
| Display | 8-inch 800 by 600 pixel touchscreen LCD |
| Port types | Frequency counter, external modulation input, external trigger input, external reference clock input / output |
| Communication interfaces | USB Host, USB Device, and LAN |
11Applications
- 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.
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.
