Decibel addition circuit
AssigneeThe Singer Company
InventorKeith Dillon
Life of this patent
Estimating the term…
Abstract
An addition circuit for adding two decibel measurements received at input terminals 12 and 14, first substracts the inputs in a subtractor circuit 16 to obtain a difference d. Then, based upon the magnitude of the difference d, the addition circuit determines the value of 10 log [1+10.sup.d/10 ] or 20 log [1+10.sup.d/20 ] in a read-only memory circuit 20. A selector circuit 24 determines which of the two input decibel measurements is the larger and controls the complementer circuit 18 so that the value of the difference d is always negative. The output of the read-only memory circuit 20 is added to the larger of the two input in an adder 22.
Claims10
A decibel addition circuit for adding two signals in the decibel form of measurement directly, comprising:
- means for determining which of said two signals is the larger,
- means for determining the difference in magnitude between said two signals,
- means responsive to said difference in magnitude for generating a signal having a value of 10 log [1+10.sup.d/10 ], and
- means for adding said signal generated by said last-mentioned means to the larger of said two signals determined by said first-mentioned means for providing the decibel sum of said two decibel signals.
Dependencies are inferred from the claim text.