HP 3048A Phase Noise System at Work

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The HP 3048A - In one of many possible configurations



HP 3048A Resources: Selection List

The list below is a summary ( and classification) of the various resources we have available here. We hope it will be useful for many others, who would like to utilize the same equipment. The list can be updated each time a new application tested, or a new document added to the lab. Obviously, it could also benefit from your own experience or comments...

... Please don't hesitate to Contact Us

Choose from the list below

HP 3048A Before Going Hands On


Before going any further, we recommend that you follow the various steps in the order listed above.

Steps 1 to 4, in the left-hand part of the selection listing, will guide you through all information necessary to build up a 3048 system, and to choose and configure the hardware which will best fit the type of Phase Noise Measurements you want to do.
Step 5 is a description of the step by step process to make SSB Phase Noise Measurements at a single discrete frequency.
Step 6, describes one possible way to automate the single frequency measurement, thus building-up a "Measurement System"
Step 7, gives information about the various software that HP originally delivered with the 3048 system. The long life of the 3048 saw many evolutions of the hardware that generated many evolutions of system controlling software.
Steps 8 to 12, in the right-hand part of the selection listing, are "live reports" generated by our own 3048 system, with many screen captures showing the process-flow of various measurements.
Steps 13 and 14, show the results obtained when making the measurements above.


HP 3048A
Technical Data 7/1992

The HP 3048A Phase Noise
Measurement System:
A Short History,


The HP 3048A System appeared for the first time in the HP general catalog in 1987, it was the successor of the 3047A which was born in 1983.

The HP 3047A System was built with the first generation of HP-IB programmable instruments. The basic system consisted of a 3582A FFT Spectrum Analyzer, a 3585A 40 MHz Synthesized Spectrum Analyzer, and a 35601A Interface. Everything was under the control of a 9836A or a 9845B computer, running a dedicated phase noise measurement program written in BASIC.

Evolutions brought by the 3048A in 1987 were many... A second generation Fast Fourier Transform Signal Analyzer, the HP 3561A, a new Phase Noise Interface HP 11848A, and updated software running on a HP9000/300 computer. A DOS version, running on HP VECTRA PC, will be available later.

The many possible configurations available in 1992 are summarized in the Technical Data paper shown on the right, and are available for download here.



HP 3048A System, Typical Residual Phase Noise

One could ask: why try to rebuild such a complex system today?

The motivation is shown in the graph below. It shows the residual noise floor of the 3048A system when measuring the Phase Noise of the 11848A Internal Source "A" versus Internal Source "B", from 10 Hertz to 100 kHz offset. This gives a clear idea of how "Clean" a signal source must be, to be lower than the 3048A's noise floor, and thus to be better than the 3048A's measurement range.

HP 3048 Internal Source A vs Internal Source B ( 10 MHz)