The HP/Agilent 3780A is a portable pattern generator and error detector engineered for validation of digital transmission systems. Operating across bit rates from 1 kb/s to 50 Mb/s, it performs closed-loop binary error detection, code error analysis for AMI/HDB3/HDB2 violations, and supports optional B6ZS/B3ZS coding. The instrument generates pseudorandom binary sequences (PRBS) and user-defined word patterns, with zero substitution capability for timing recovery characterization.
## Technical Specifications
• **Bit Rate Range:** 1 kb/s to 50 Mb/s
• **Binary Error Detection:** Closed-loop bit-by-bit detection on any pattern generated by the instrument (excluding added zeros or alternating words)
• **Code Error Detection:** Violations of AMI, HDB3, or HDB2 coding rules; optional AMI, B6ZS, or B3ZS support
• **Pattern Generation:** PRBS sequences, user-defined WORD generation, zero substitution
• **Clock Sources:** Internal crystal clocks with clock recovery; external clock input 1 kHz to 50 MHz; three internal crystal options (1.544, 6.312, 3.152 MHz with Option 102)
• **Clock Offset:** ±50 ppm range (except Option 099)
• **Data Interfaces:** Binary clock and data; ternary coded data (RZ AMI or coded)
• **Data Output Formats:** NRZ or RZ; binary or ternary coding (HDB3/HDB2 or B6ZS/B3ZS)
• **Clock Output:** 75 Ω nominal to ground; 3 V ±0.3 V pk-pk; transition time < 4 ns
• **Data Output Impedance:** 75 Ω nominal to ground
• **Receiver Equalization:** Automatic at 2 Mb/s, 8 Mb/s, and 34 Mb/s
• **Error Display:** COUNT or BER over selectable gating periods; LED readout
• **Result Logging:** External printer output with graphical presentation
• **Frequency Offset Measurement:** Available at standard PCM/TDM transmission rates
## Key Features
• Automatic pattern recognition and synchronization for performance validation
• Dual interface support: binary clock/data and ternary coded configurations
• Selectable gating periods for BER and error count analysis
• Multiple crystal frequency options via plug-in modules
• Frequency offset generation and measurement capability
## Typical Applications
Validation of digital transmission equipment, regenerator timing recovery analysis, systematic error detection through zero substitution, BER characterization across PCM/TDM networks, codec performance evaluation.
## Compatibility & Integration
Available with Option 001, 002, 099, 100, 101, and 102 for customized clock frequencies and codec variants.
