The present invention relates to attenuators and more particularly decade attenuators.
In traditional decade attenuators with multiple taps, compensation for the interaction between steps is difficult to impossible to compensate for. Variable capacitors have been utilized in the prior art attenuators but they perform poorly in extreme environments and they are sensitive to high volume production processes. These capacitors and special high voltage switches for use for high voltage attenuation are quite expensive and bulky.
In accordance with the preferred embodiment of the present invention, an attenuating divider circuit provides signal compensation by a compensation signal which varies with the divider output selected. The basic RC compensation provided for each attenuator path is fine-tuned by this compensation signal which varies with the divider output, i.e. attenuating path, selected. The adjustments in compensation can be accomplished by various techniques which cause the compensation signal to assume the desired electrical characteristics as the various attenuator paths are selected. In the preferred embodiment, variable resistors are provided as alternate paths for the compensating signal in response to the selection of the corresponding signal attenuation path in the divider.
The compensating signal is provided to a common electrical point of the divider via an additional signal compensation circuit element. The particular resistance value selected in combination with this additional signal compensation element, e.g. a capacitor, acts in shunt with compensation elements in the divider circuit to achieve a desired combined RC value for that attenuation path and thus provide the high frequency signal compensation of the output signal.