The HP/Agilent 5315B is a 100 MHz universal counter delivering frequency, period, time interval, ratio, and totalize measurements with 8-digit LED display resolution. Its metal cabinet construction provides enhanced electromagnetic shielding suitable for laboratory and rack-mounted test systems. Expandable to 1 GHz with optional Channel C, the 5315B combines flexible input coupling, variable trigger control, and multiple time base options for precision frequency measurement from 0.1 Hz to 100 MHz.
## Technical Specifications
**Measurement Capabilities**
• Frequency: 0.1 Hz to 100 MHz; up to 1 GHz with Option 003 (Channel C)
• Period: 10 ns to 10 s
• Time Interval: Single-shot (100 ns resolution), Averaging (10 ps resolution), and Delay modes
• Ratio: Two-input frequency ratio measurement
• Totalize: 0 to 100 MHz, manual or external gating via Input A or Input B
**Input Channels A & B**
• Frequency Range: DC-coupled 0 Hz to 100 MHz; AC-coupled 30 Hz to 100 MHz
• Sensitivity: 10 mV rms to 10 MHz; 25 mV rms to 100 MHz; 75 mV peak-to-peak pulse (5 ns minimum width); continuously variable to 500 mV rms
• Dynamic Range: 30 mV to 5 V peak-to-peak (0–10 MHz); 75 mV to 5 V peak-to-peak (10–100 MHz)
• Signal Operating Range: +2.5 Vdc to −2.5 Vdc
• Input Impedance: 1 MΩ nominal shunted by <40 pF
• Attenuator: X1 or X20 nominal
• Trigger Level: Variable +2.5 Vdc to −2.5 Vdc with independent slope selection
• Filter: 100 kHz low-pass, switchable on Channel A
**Channel C (Option 003)**
• Frequency: 50 MHz to 1 GHz at 25 mV sensitivity to 100 MHz
**Time Base Options**
• Standard: 10 MHz, <3 parts in 10⁷/month aging, ±5 parts in 10⁶ temperature stability (0–50 °C)
• Option 001 (TCXO): 10 MHz, <1 part in 10⁷/month aging, ±1 part in 10⁹ temperature stability (0–40 °C)
• Option 004 (Oven): 10 MHz, <3 parts in 10⁸/month aging, ±2 parts in 10⁸ temperature stability (0–50 °C)
## Key Features
• Metal cabinet for RFI immunity and mechanical durability
• Reciprocal counting at low frequencies for enhanced resolution
• AC/DC coupling selection per input
• Selectable attenuator for extended dynamic range
• Multiple time base stability grades
## Typical Applications
• Frequency and period measurement in RF/microwave development
• Precision time interval analysis and jitter characterization
• Signal ratio and event counting in automated test systems
• Laboratory calibration and standards verification
## Compatibility & Integration
Rack-mountable metal construction integrates into benchtop and ATE environments with minimal EMI considerations.
