The HP/Agilent 58503A GPS Time and Frequency Receiver delivers primary standard-level time and frequency references by locking to GPS satellite signals. This 6-channel parallel-tracking receiver provides two 10 MHz outputs and 1 pulse per second (1 PPS) timing with frequency accuracy better than 1 × 10⁻¹² over one-day averages and time accuracy under 110 ns relative to UTC. The instrument achieves exceptional phase stability through HP SmartClock technology, delivering 1.5 × 10⁻¹² aging per year and 5 × 10⁻¹² root Allan variance at 1 second. In holdover mode, frequency drift remains under 1 × 10⁻¹⁰ per 24 hours with phase accumulation below 8.6 µs after 24 hours unlocked.
## Technical Specifications
**GPS Receiver & Signal Acquisition**
• 6-channel parallel-tracking receiver
• C/A code, L1 carrier
• Lock-on time: 5 to 25 minutes
• HP SmartClock / HP Enhanced GPS technology
**Frequency & Time Outputs**
• 10 MHz: two outputs at >1 Vrms into 50 Ω load
• 1 PPS: >2.4 V pulse, 26 µs width, <750 ps rms timing jitter (locked)
• 1 PPS leading edge jitter: <50 ps rms (locked)
**Accuracy & Stability**
• Frequency accuracy (locked): better than 1 × 10⁻¹² (one-day average)
• Time accuracy (locked): <110 ns to UTC (95% probability); 20 ns typical (1 Sigma)
• Time base stability: 1.5 × 10⁻¹² per year
• Root Allan variance (1 sec): 5 × 10⁻¹²
• Holdover aging: <1 × 10⁻¹⁰ per 24 hours; phase accumulation <8.6 µs after 24 hours
**Phase Noise (10 MHz, locked)**
• 10 Hz offset: -85 dBc/Hz
• 100 Hz offset: -135 dBc/Hz
• 1 kHz offset: -140 dBc/Hz
• 10 kHz offset: -145 dBc/Hz
## Key Features
• Intelligent holdover mode compensates for environmental changes during GPS signal loss
• Front panel LED indicators: Power, GPS lock, Holdover, Alarm
• Optional 16-character vacuum-fluorescent display
• N-type (female) antenna connector
• RS-232-C DTE interface for remote monitoring and control
• Universal AC input 90-260 Vac, 50-60 Hz; DC power options available
• Over 500,000 hours MTBF with quartz oscillator
## Typical Applications
Precision frequency and time distribution for calibration laboratories, R&D facilities, and manufacturing environments requiring traceable primary standards and long-term frequency stability.
