Agilent/Keysight 438A

The Agilent/Keysight 438A is a dual-channel power meter designed for automated test equipment (ATE) systems requiring precise measurement of power levels and ratios across two independent sensor inputs. Its compact 212.6 mm width and 88.5 mm height conserve rack space while delivering measurement accuracy to ±0.5% in single-channel linear mode and ±0.02 dB in log mode. The instrument operates across 100 kHz to 50 GHz with a dynamic range of 50 dB and power measurement span from −70 dBm to +44 dBm, enabling characterization of signals from 100 pW to 25 W.

– Technical Specifications

• Frequency Range: 100 kHz to 50 GHz (sensor dependent)
• Power Range: −70 dBm to +44 dBm (100 pW to 25 W) (sensor dependent)
• Dynamic Range: 50 dB
• Measurement Accuracy (Single Channel): ±0.5% linear mode; ±0.02 dB log mode
• Measurement Accuracy (Dual Channel): +1% linear mode; ±0.04 dB log mode
• Power Reference: 1.00 mW at factory calibration (±0.7% traceable to NIST)
• Reference Accuracy: ±1.2% worst case (±0.9% RSS) over 1 year
• Automatic Zeroing: ±0.5% full scale on most sensitive range
• Cal Factor Adjustment: 1% to 150% in 0.1% increments
• Display: Four-digit with 20% over-range; five-digit high-resolution mode
• Resolution: 0.001 dB minimum

– Key Features

• Dual-channel measurement supports A, B, A−B, B−A, A/B, and B/A modes for ratio and difference analysis
• Programmable digital filter with AUTO mode delivers 0.01 dB resolution on settled readings
• Independent offset values (dB) assignable to each channel
• Programmable high and low power limits enable unattended monitoring
• Automatic self-calibration to 1.00 mW reference output
• Four-digit display with annunciators for measurement mode, Cal Factor, offset, range, filter status, and error conditions

– Typical Applications

• Gain compression measurement via ratio mode
• Multi-port device characterization
• Automated power monitoring in ATE environments

– Compatibility & Integration

• Compatible with Agilent/HP 8480 series thermocouple and diode power sensors (E-series sensors not supported)
• Standard GPIB interface for bench and system control
• Option 700 enables MATE CIIL (Control Interface Intermediate Language) operation
• Software-compatible with EPM series power meters operating in 437B/438A language mode