From a Simple Audio Oscillator
to a Complete Signal Source & Generator Product Line

Here is a very short summary of the four chapters dedicated to signal sources and generators
in the first period of this "Quick Tour" (1939-1960):

The HP 200A, a simple but revolutionary audio oscillator, was the first instrument developed by HP in 1939. It was a successful product and can be considered as the fundamental reason of the company's creation, rapid growth, and quick commercial success. During the five years after the start of the company, excluding war effort activity, most of the development of Hewlett Packard's new products were variations and evolution of Bill Hewlett's original 200A audio oscillator. The 1945 catalog shows 10 such instruments among a total of 24 items listed. In the 1948 catalog, almost 10 years after the start of the company, 16 instruments among the 39 total listed, were signal sources or generators. And to complete these two decades, by the end of 1959, more than 30 instruments listed in the catalog were audio and test oscillators, RF and microwave or pulse generators, and even some swept frequency oscillators.

The current chapter will try to show the evolution of this very important product line in the overall Hewlett Packard production during the following two decades: the 1960s and 1970s. Needless to say that the technology evolution during these two decades had a considerable impact on product diversification. As usual during this Quick Tour we will choose the most significant devices to illustrate the story. But even limiting references to the most important instruments, we need to clarify and divide the overall product line into five different categories. In respect of the classification of the original Hewlett Packard catalogues, the categories are the following:

1. Audio and Test Oscillators
2. Signal Generators
3. Function Generators
4. Sweep Oscillators
5. Pulse Generators

Note:

Frequency synthezisers are of course, signal sources too. From the birth of the very first one in 1963 up to the end of the covered period in 1980, the quantity of frequency syntheziser produced by HP was such that a dedicated chapter was necessary. This chapter is already on line: Frequency Synthezisers 1960-1980