"No analog! No analog!" Those words echoed throughout a fair-sized electronics repair shop in Upstate New York. They were triggered by the front cover of a service manual I had presented to the shop's proprietor, which displayed a high-mileage analog reel-to-reel multitrack audio recorder. Said proprietor was surrounded by digital consumer electronics devices, and he clearly wanted nothing to do with the ancient technology embodied in that reel-to-reel recorder. Not terribly surprising: The world of consumer electronics has all but abandoned analog technology.
"That won't happen here," attest many in the RF/microwave industry, where analog electronics has been the basis of so many systems and their components for so many years. Indeed, systems like radar, surveillance receivers, and electronic-warfare platforms rely heavily on analog technology and components, and there is no digital counterpart for the high-power amplifiers needed in most RF/microwave transmitters.
Yet, the signs of a "digital takeover" are there in much of RF/microwave technology, just as they were earlier in consumer electronics. In the consumer/pro-audio world, most audio engineers could not have foreseen a time when analog recording media would become antiquated, and that almost all audio recording would be performed by means of an analog-to-digital converter (ADC). Of course, the frequencies are different in the RF/microwave world, but the ADCs are also getting faster. The suppliers of those components are tenacious in their efforts to insert their converters earlier and earlier in the receiver signal-processing chain and, similarly, with digital-to-analog converters (DACs) in the transmitter signal chain.
Progress is not to be denied. Most RF/microwave systems must communicate at some point with a digital systemsuch as a radar controller, cellular base station, or even a simple personal computer (PC)and the increasing digital content in RF/microwave systems provides a straightforward means of performance troubleshooting.
At present, it would seem that many analog RF/microwave components cannot be replaced (readily, at least) by digital devices. Such components as the low-noise amplifiers (LNAs) in receivers help set the sensitivity when pulling in low-level signals, and power amplifiers in transmitters establish the ultimate range of the system.
But what of that inevitable day when digital technology becomes as much a part of the RF/microwave industry as it has become in consumer electronics? Commercial analog radios and, certainly, wireless telephones are few and far between, and are usually discarded and replaced rather than repaired. Military electronics customers, however, rely on a large number of "legacy" systems in which analog electronics technologies will likely not be replaced. When it comes time to repair those systems, will customers even be able to find replacement parts for them? They may well be met by that unfortunate refrain: "No analog!"