1. A method for equalizing a signal comprising:
accepting a set of frequency bands and a corresponding set of band gains;
processing the band gains to form filter gains for, and interference between, each of a plurality of infinite impulse response (IIR) filters, such that a combined gain comprising a sum of the filter gains of the plurality of IIR filters in all of the frequency bands due to the interference between filters in adjacent bands is approximately equal to the band gains.
2. A method according to claim 1, wherein the processing step includes:
forming a matrix which relates at least one of the filter gains to at least one of the band gains.
3. A method according to claim 2, wherein the matrix is precomputed.
4. A method according to claim 1, wherein the processing step includes anticipating equalization with a normalization filer, such that a further combined gain of the normalization filter and the combined gain of the plurality of filters approximate the set of band gains in the respective frequency bands.
5. A method according to claim 4, wherein the normalization filter is a cascade of shelf filters.
6. A method according to claim 5, wherein the shelf filters comprising the cascade of shelf filters are formed based on the frequency bands and band gains.
7. A method according to claim 1, wherein the combined gain is obtained by a cascade of the plurality of filters.
8. A method for equalizing a signal comprising:
accepting a transfer function magnitude;
accepting a set of frequency bands;
forming a set of band gains corresponding to the set of frequency bands;
processing the band gains to form filter gains for, and interference between, at least one of a plurality of infinite impulse response (IIR) filters, such that a combined transfer function magnitude comprising a sum of the filter gains of a cascade of the plurality of IIR filters due to the interference between filters in adjacent bands is approximately equal to the accepted transfer function magnitude.
9. A method according to claim 8, wherein the step of accepting the set of frequency bands comprises forming the set of frequency bands.
10. A method according to claim 8, wherein the processing step includes anticipating equalization with a normalization filter, wherein a further combined transfer function magnitude of the normalization filter and the cascade of the plurality of filters approximates the accepted transfer function magnitude.
11. A method for equalizing a signal according to at least one time-varying control, comprising:
forming a table of sets of filter gains corresponding to sets of respective frequency bands, the table being indexed by at least one of said time-varying controls, and wherein at least one set of filter gains and associated interference between filters is such that a sum of gains due to the interference between a cascade of a plurality of infinite impulse response (IIR) filters having said filter gains and said interference is approximately equal to a set of desired band gains in the respective frequency bands;
producing a set of interpolated filter gains in response to the time-varying control.
12. A method according to claim 1, wherein forming the interference includes determining respective transition frequencies for the plurality of IIR filters.
13. A method according to claim 8, wherein forming the interference includes determining respective transition frequencies for the plurality of IIR filters.
14. A method according to claim 11, further comprising determining respective transition frequencies for the plurality of IIR filters to obtain the interference.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An improved curtain rolling buffer apparatus, comprising a casing, a bushing, a hub, a cap and a rotor; wherein:
the casing has a strut extended outwards from one end thereof in the center that has a cavity formed therein, and an annular indented recess and a hollow interior formed on another end, the hollow interior having a bottom side with a stub shaft located thereon;
the bushing has a round aperture formed on one end in the center thereof to couple with the stub shaft of the casing, and an annular jutting ring extending outwards from an end surface of another end thereof;
the hub as a hub body on one end that has a trough formed on the periphery, and a rod on another end thereof with an elongated chamfer section formed thereon;
the cap has an annular retaining ring located on one end thereof to encase and press an oil seal located on the end surface of another end of the bushing to prevent the oil seal from falling out, and a cap rim located on another end to couple with the annular indented recess of the casing; and
the rotor has an elongated cavity formed in the center of one end thereof to couple with the elongated chamfer section of the rod of the hub;
wherein during extending a curtain with the curtain rolling buffer apparatus, a spring surrounding an axle in the bushing and the hub are coupled and turned clockwise, the spring being extended outwards and running idle, and the spring force being smaller than a lube oil pressure such that the curtain is pulled and extended smoothly; on the contrary, during winding and retracting the curtain by turning counterclockwise, the spring in the bushing being tightened and driving the bushing to rotate together counterclockwise, the bushing being retarded by the lube oil and generating a reaction force in an opposite direction to reduce the winding speed to retract the curtain at a lower speed.
2. The improved curtain rolling buffer apparatus of claim 1, wherein the bushing further has the axle located in the center which has a center hole formed therein, the axle being surrounded by the spring on the periphery.
3. The improved curtain rolling buffer apparatus of claim 1, wherein the bushing has chamfer corners to form gaps with the hollow interior, the peripheral sides of the bushing and the hollow interior forming a space for containing the lube oil.