Signal level detector with automatic switching between extended linear and square law dynamic ranges
AssigneeAT&T Bell Laboratories
InventorRoland J. Turner
Life of this patent
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Abstract
A signal level detector including a diode envelope detector has a characteristic having both square-law and linear-law ranges separated by an intermediate transition range of variable-law operation. The detector is provided with circuits (38, 47, 48) to extend the linear-law range of the characteristic to overlap at least a part of the variable-law transition range. A circuit (66) is provided to detect operation through an input signal level transition point between said square-law range and the extended linear-law range for automatically modifying (39) the level detector circuit so that the voltage output thereof is continuously indicative of input power level through all of said ranges.
Claims11
A signal level detector including a circuit having both linear-law and square-law ranges of operation and an intermediate variable-law range of operation and comprising
- means for extending the linear-law range of said detector to overlap at least a portion of said intermediate variable-law range, said extending means comprising means for biasing output signals of said detector during at least said variable-law range of operation to levels corresponding approximately to an extrapolation of said linear-law range of operation.
A signal level detector including a circuit having both linear-law and square-law ranges of operation and an intermediate variable-law range of operation and comprising
- means for extending the linear-law range of said detector to overlap at least a portion of said intermediate variable-law range, and
- means for amplitude compressing output signals of said detector.
A signal level detector including a circuit having both linear-law and square-law ranges of operation and an intermediate variable-law range of operation and comprising
- means for extending the linear-law range of said detector to overlap at least a portion of said intermediate variable-law range,
- a voltage difference amplifier,
- an envelope detecting signal path circuit electrically connected between an RF signal input connection of said level detector and a first input of said amplifier,
- means for biasing at least a portion of said envelope detecting signal path circuit to a predetermined nominal operating point, and
- a temperature compensating reference current path circuit electrically connected between said biasing means and a second input of said amplifier.
A signal level detector including a circuit having both linear-law and square-law ranges of operation and an intermediate variable-law range of operation and comprising
- means for extending the linear-law range of said detector to overlap at least a portion of said intermediate variable-law range,
- an envelope detecting signal path circuit electrically connected for coupling level detector input signals to said extending means and including a diode connected in an envelope detecting circuit, said diode having an input power versus output voltage characteristic including a low signal range represented by said square-law range, a high signal range represented by said linear-law range, and an intermediate signal range of variable-law operation, and
- means, in said extending means, for biasing an output of said envelope detecting signal path circuit by an amount corresponding approximately to the voltage difference between corresponding input power points in said variable-law range of said characteristic and a linear extrapolation of said linear-law range of said characteristic through an input signal range including said variable-law range.
The signal level detector in accordance with claim 8 in which
- said translating means includes means for amplitude compressing said output signals of said envelope detecting signal path circuit.
Dependencies are inferred from the claim text.