Method and apparatus for determining the value of a sample in the mth position of an ordered list of a plurality of samples

Claim 3

The method of claim 1 wherein said step for determining ones of said truncated samples having values which correspond to a desired m-tile comprises the steps of: calculating the relative value of each truncated sample compared with every other truncated sample; and evaluating the calculated relative values for each truncated sample to determine if the value of said truncated value has the relative position of said desired M-tile.

Claim 4

The method of claim 1 wherein said step for determining ones of said truncated samples having values which correspond to a desired M-tile comprises the steps of: predetermining for every possible value of each truncated sample a result which identified which of the truncated samples have the desired M-tile value; and generating said predetermined result in response to the values of truncated samples corresponding to digital samples of each respective group.

Claim 5

The method of claim 3, including the further steps of: predetermining for every possible value of each truncated sample a further result which is a truncated sample having the desired M-tile value; and generating said desired M-tile valued truncated sample in response to the values of truncated samples corresponding to digital samples of each respective group.

Claim 10

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples and (n-R) is greater than one; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired M-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means, responsive to said selection control signals, for generating a further digital sample for each respective group, said further digital sample substantially representing an average of n-bit digital samples corresponding to said indicated truncated samples, and wherein a sequence of said further digital samples represent a filtered output signal.

Claim 11

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples and (n-R) is greater than one; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired M-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means, responsive to said selection control signals, for generating a further digital sample for each respective group, said further digital sample substantially representing an average of n-bit digital samples corresponding to said indicated truncated samples, and wherein a sequence of said further digital samples represent a filtered output signal.

Claim 12

Apparatus of claim 7, wherein said M-tile producing means includes a digital memory means having respective address input terminals responsive to said truncated samples and respective output terminals for producing said selection control signals, said digital memory means being preprogrammed to generate said selection control signal corresponding to said truncated samples representing said desired M-tile value.

Claim 13

Apparatus of claim 7 wherein said M-tile producing means comprises: a plurality of comparing means each comparing the value of a truncated sample to values of mutually different other truncated samples within a respective group, for generating a signal indicating whether said truncated sample is greater than or less than said other truncated sample; and means responsive to said plurality of indication signals generated by said comparing means, for producing said selection control signal if the number of greater-than indications and less-than indications are ascertained to be within predetermined limits.

Claim 14

Apparatus of claim 9, wherein: each of said plurality of comparing means comprises a comparator having a first input terminal responsive to a truncated sample, a second input terminal responsive to a mutually different other truncated sample, a first output terminal for indicating that the value of the signal at said first input is greater than that at said second input, and a second output terminal for indicating that the value of the signal at said second input is greater than that at said first input; and said selection signal producing means comprises first means coupled to said first output terminals of said plurality of comparators for generating an output signal having a first state if the number of values of said other truncated samples greater than said truncated sample is ascertained to be fewer than a first predetermined number and a second state otherwise, second means responsive to said second output terminals of said plurality of comparators for generating an output signal having a first state if the number of values of said other truncated samples less than said truncated sample is ascertained to be fewer than a second predetermined number and a second state otherwise, and an AND gate having respective input terminals responsive to the output signals from said first and second means and having an output terminal for generating said selection control signal when the signals at both inputs are in said first state.

Claim 15

Apparatus of claim 10, wherein said first and second signal generating means comprise first and second digital memory means respectively, each having address input terminals coupled to said plurality of first and second output terminals respectively of said comparators and respective output terminals coupled to said input terminals of said AND gate.

Claim 16

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples and (n-R) is greater than one; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired m-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means for generating the average of n-bit digital samples corresponding to said ones of said truncated samples within a respective group, and generating an output sample for each respective group; and means for providing successively generated output samples as a filtered output signal.

Claim 17

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples and (n-R) is greater than one; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired m-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means for generating the average of n-bit digital samples corresponding to said ones of said truncated samples within a respective group, and generating an output sample for each respective group; and means for providing successively generated output samples as a filtered output signal.

Claim 18

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired m-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means responsive to n-bit digital samples corresponding to said ones of said truncated samples, for providing residual samples corresponding at least to the lesser significant bits of said n-bit digital samples; means responsive to residual samples and said selection control signals for producing a residual sample having the average value of residual samples corresponding to said ones of said truncated samples; and means for merging one of said ones of said truncated samples and said residual sample having said average value to form an output digital sample; and means for providing successively generated output digital samples as a filtered output signal.

Claim 19

Apparatus for filtering a signal represented by a sequence of n-bit digital samples, (n an integer) said apparatus comprising: means responsive to said n-bit digital samples for generating truncated samples from said n-bit digital samples, said truncated samples being (n-R)-bit samples where R is an integer less than n, the (n-R)-bits of the truncated samples correspond to the more significant bits of said n-bit digital samples; M-tile producing means, coupled to said means for generating truncated samples and responsive to respective groups of truncated samples for determining ones of said truncated samples in each respective group having values corresponding to a desired m-tile of said truncated samples and producing respective selection control signals indicating said ones of said truncated samples having the desired M-tile; means responsive to n-bit digital samples corresponding to said ones of said truncated samples, for providing residual samples corresponding at least to the lesser significant bits of said n-bit digital samples; means responsive to residual samples and said selection control signals for producing a residual sample having the average value of residual samples corresponding to said ones of said truncated samples; and means for merging one of said ones of said truncated samples and said residual sample having said average value to form an output digital sample; and means for providing successively generated output digital samples as a filtered output signal.

Claim 20

Apparatus of claim 13, further including means for providing said one of said ones of said truncated samples comprising a digital memory means having respective address input terminals responsive to said truncated samples, and having data output terminals, said memory means being preprogrammed to produce, at said data output terminals, a sample having a value corresponding to the value of said one of said ones of said truncated samples which sample is merged with said residual sample.

Claim 21

Apparatus of claim 14, wherein said average valued residual sample producing means comprises: means having respective input terminals responsive to said residual samples and said selection control signals for producing the sum of said corresponding residual samples; and dividing means having a dividend input responsive to said sum, having a quotient output, and having a divisor input responsive to said selection control signals, for dividing said sum by a predetermined dividing factor to produce said average valued residual sample.

Claim 22

Apparatus of claim 15, wherein said sum producing means comprises: a plurality of AND gate means, having respective first input terminals responsive to mutually different residual samples and each having a second input terminal responsive to a corresponding selection control signal and each having a data output terminal; and summing means having respective input terminals coupled to said data output terminals of said plurality of AND gate means, for producing said sum.