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Azur Electronics

The HP 8750A Storage Normalizer was bought just to find out what it can do with either my Network or Spectrum Analysers! The original cost was $1,600 in 1980. The Operating Manual is available for download, but not the Service Manual.

Front Panel showing controls
Rear Panel showing Interface card and Special D-type Connector
Top view with covers removed
Bottom view with covers removed
Interface Card plugged-in to Rear Panel.

This card is labelled 'Network Analyser' with the part number 08750-60048.

"With HP's versatile 8750A Storage-Normalizer, you can make your network analyzer or spectrum analyzer measurements faster, easier, and more accurately through the simple addition of digital storage and normalization. This useful instrument accessory is directly compatible via a single interface cable with the following recently produced or appropriately modified instruments; the 8755 Frequency Response Test Set, the 8407A/8412A, the 8410/8412A, the 8754A and 8505A Networks Analyzers and 8557A, 8558B, and 8565A Spectrum Analyzers. A special 1/0 Adapter (opt 001 or opt 002) is available for interfacing instruments (like 140 Series Spectrum Analyzers) that are not directly compatible with the 8750A. An external oscilloscope can then be used for digitally stored and normalized displays. (The 8750A is not compatible with the 8414A Polar Display or the polar mode of the 8505A or the 8754A.) In network analyzer applications, digital storage always yields a flicker-free display of the complete device response, facilitating easy adjustment of test devices under slow sweep conditions. Measurement accuracy is also improved since frequency response errors can be automatically removed through digital normalization. This effectively eliminates the need to manually record calibration traces on a CRT or x-y recorder and allows high resolution measurements of attenuator, amplifier, or filter passband flatness. In spectrum analyzer applications, the 8750A's digital storage feature simplifies many difficult tests requiring slow scan times such as high resolution modulation measurements. Drift tests are also easy since two traces, a stored reference and the current input, can be displayed simultaneously. Hard copy documentation can be obtained quickly and easily since data can be frozen on the CRT for straightforward CRT photography or outputted to an x-y recorder at a constant 30 second sweep rate." [HP Catalogue 1980] 

October 2008

Bought the 8750A (S/N 2403A) on eBay UK. To connect the 8750A to the Network Analyser 8412B Phase-Magnitude Display, a special inter-connecting cable (08750-60034) is required. This is available from GLK Instruments for $160.

Sadly, I do not have one of these cables so testing is held up until I find another solution!

July 2011

I received an email from Tim Webb at procurement@sonic.net who had two of these cables for sale. I bought one at a very fair price. Tim is a highly recommended seller on ebay (see silicon-valley-excess). Hopefully I will get some time to progress this project.

March 2016

Downloaded Operating and Service Manual (thanks Didier). This describes the plug-in cards required: A5 08750-60005 Board Assembly, Network Analyzer Interface (although I have the later 08750-60048 version) and A5 08750-60009 Board Assembly, Spectrum Analyzer Interface. Parts Lists and Schematics are provided.

November 2016

A bit more research implies that the 8750A can be used with an Oscilloscope display as well as a Spectrum Analyser. This needs the Spectrum Analyser Interface A5 08750-60009 Board Assembly and a Direct Interface Cable 08750-60008 which has the special D-type connector at one end and 5 BNC connectors at the other end. These 2 items are on my Wanted list, please Contact Me if you them for sale.