Method and circuit for envelope detection using a peel cone approximation
AssigneeChun-Shan Institute of Science and Technology
InventorScott Yeh
Life of this patent
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Abstract
An envelope detection method by using a peel cone approximation concept and an envelope detection circuit which implements the envelope detection method are disclosed. The envelope detection circuit includes an absolute value-determining circuit, a maximum/minimum value-determining circuit, a plurality sets of comparison circuits, an address encoder, a read only memory (ROM), and a multiplier/adder. A delaying circuit for synchronization is further included in the envelope detection circuit. With the method and the circuit for an envelope detection by using a peel cone approximation, advantages of a compact circuit structure, less operation latency, a low approximation error and a low cost are all achieved.
Claims12
An envelope detection method by using a peel cone approximation, comprising steps of:
- selecting a peel cone surface passing through an original point of a coordinate system and intersected with the Z axis by a contained angle of 45 degrees;
- selecting a plurality of different planes passing through the original point and cutting said peel cone surface with a 45-degree contained angle so as to make an approximation to said peel cone surface with a 45-degree contained angle by combining the plurality of different planes;
- solving a set of simultaneous linear equations with two variables based on values of x and y with respect to each plane to obtain constant values of a and b with respect to each plane function;
- and
- judging the plane where the values of x and y to be used to perform an envelope detection operation is substantially located and performing multiplication and addition operations based on the obtained constant values of a and b to find a square root of the sum of two squares of the values of x and y.
An envelope detection circuit by using a peel cone approximation, comprising:
- an absolute value-determining circuit for determining positive values for incoming values of x and y with a 16-bit notation;
- a maximum/minimum value-determining circuit for determining a maximum value and a minimum value for the incoming values of x and y after their positive values are determined;
- a plurality of comparison circuits for comparing different combinations of the values of x and y and generating an output data;
- an address encoder for converting the output data of the plurality of comparison circuits into an address signal;
- a read only memory for selecting corresponding constant values of a and b stored inside the read only memory in advance based on the address signal;
- and
- a multiplier/adder for performing multiplication and addition operations on the constant values of a and b from the read only memory together with the maximum value and the minimum value of the positive values of x and y from the maximum/minimum value-determining circuit and outputting a square root of the sum of two squares of the values of x and y.
Dependencies are inferred from the claim text.