A New Type of Q Meter Using Variable-Width Pulse Excitation

There are several well-known methods of measuring the Q of a resonant circuit, each with its limitations. Errors are introduced into measurements of high-Q values due to loading effects and radiation losses. A theoretical basis for the development of a Q meter which will not load a high-Q resonant circuit has been established. This new type of Q meter will use variable-width pulse excitation in lieu of sinusoidal excitation and will use elapsed-time Q-measurement techniques. It is seen that if the width of the exciting pulse is known, the resonant frequency of the resonant circuit can be directly determined. A Q meter using this approach will actually yield more information about a resonant circuit than can be determined using presently standard-type Q meters and will yield this information well beyond the Q and frequency capabilities of today's Q meters.