This module is a component of several Hewlett Packard spectrum analyzers based on the 70K series Modular Measurement System (MMS). It is easiest to quote the Agilent website for an overview:
The Agilent 70903A provides narrow resolution bandwidths, from 100 kHz to 3 MHz and can be used in any of the configured systems. This intermediate frequency (IF) section provides signal processing elements required for spectrum analyzers and lightwave signal analyzers. The Agilent 70903A maximizes measurement speed using 10% incremental bandwidths. Wider bandwidths offer the most speed, whereas narrow bandwidths offer more resolution and sensitivity. The 10% incremental bandwidth steps offer you the best choice of bandwidth sizes. The bandwidths can also be changed in a 1, 3, 10 sequence. Calibrated logging amplifiers provide superb amplitude accuracy for the analyzers. The 21.4 MHz IF output on the Agilent 70903A allows connection to other instruments such as demodulators, digitizers, and oscilloscopes.
HP/Agilent 70903A Features:

Provides narrow resolution bandwidths from 100 kHz to 3 MHz
Bandwidths in 10% increments
Logging amplifier and detector
21.4 MHz IF output allows connection to other instruments
Also, from the HP Installation Manual:
The HP 70902A IF Section is a 1/8-width module, providing a resolution bandwidth of 100 kHz to 3 MHz, designed for use in HP 70000 Modular Measurement Systems. The module processes a 21.4MHz signal from a spectrum analyzer RF section or external mixer interface module. A detected video signal is produced and routed to the video processor in the local oscillator. The module contains resolution bandwidth filters, log amplifiers, detection circuitry, and video filters. The HP 70902A can be used with an HP 70902A in a single system to provide resolution bandwidths of 10 Hz to 3 MHz.

The HP 70902A is a slave module and as such is controlled by the system master (for example, the HP 70900A(B) Local Oscillator).
If desired, we can arrange to have the module calibrated before shipment, either as a stand-alone item, or as part of a complete system. Please contact us to discuss these options.

Shipping Policies