HP / Agilent 5328A 100 MHz Universal Counter

The HP/Agilent 5328A is a 100 MHz universal counter delivering precision frequency and time interval measurements for electronic testing, calibration, and research. Introduced in 1976, this modular instrument combines ROM-controlled measurement cycles with a 9-digit LED display to support frequency, period, time interval, ratio, and totalize functions. Single-shot time interval resolution reaches 100 ns standard, while repetitive interval measurements achieve better than 10 ps resolution down to 100 ps intervals. A comprehensive trigger system with adjustable levels from −2.50 V to +2.50 V and switchable AC/DC coupling accommodates diverse signal types.

Technical Specifications Measurement Ranges

Frequency (burst and CW): DC to 100 MHz

Period and period averaging

Time interval: 100 ns single-shot resolution; <10 ps for repetitive intervals ≥100 ps

Ratio (e.g., C/A) and totalize

Scale and arming functions Display & Output

9-digit LED readout with leading zero blanking

Gate output: TTL levels, rear panel

Timebase output: TTL levels, rear panel

Marker outputs: operational to 100 MHz for oscilloscope triggering Input System

Trigger level range: −2.50 V to +2.50 V

Trigger level resolution: 1 mV display

Each channel: attenuator, trigger slope detector, level control, AC/DC coupling

Switchable impedance (1 MΩ / 50 Ω) with Option 040 Timebase

Standard crystal oscillator; aging <3 × 10⁻⁷ per month

Line voltage stability: <1 × 10⁻⁷ for 10% change

Option 010 (oven oscillator): aging <5 × 10⁻¹⁰ per day Sampling

Measurement interval: <2 ms to HOLD (variable)

Key Features

Modular architecture supports frequency extensions to 512 MHz (Option 030) and 1300 MHz (Option 031)

Universal Module (Option 040): 10 ns single-shot resolution, improved averaging, A→B marker, hysteresis compensation

HP-IB interface (Option 011): remote programming and digital output at up to 500 readings/sec

Display storage preserves readings between samples

Typical Applications Frequency and period characterization, time interval analysis, signal ratio measurements, event counting, and precision calibration in RF and digital circuit validation.

Compatibility & Integration HP-IB interface option enables integration into automated test systems with maximum data throughput of 500 readings/sec.