Method and apparatus for compacting digital time series data for display on a digital oscilloscope

Claim 3

Method according to claim 1 characterized in that the selecting consisting of iteratively considering the values of k1 pairs of max/min values, p i ,. . ., p i+k1-1 , where k1 is at least 2, from the auxiliary memory and of k2 of the most recently stored display values e i-k2 ,. . .,e i-1 , in the display image memory, where k2 is at least 1, selecting, based on said k1 pairs and k2 display values, k1 display variables, e i ,. . .e i+k1-1 , said k1 display variables in the display memory, repeating these steps until the display image memory is filled.

Claim 4

Method according to claim 2 characterized in that k1=2 and k2=1 and that the choosing consists of determining which condition k, k=1,. . .6, of Table 1 selecting for the applicable case K, K1,. . .G, variables v 1 and v 2 according to Table 1 and as logical variable f according to Table 2 TABLE 1 ______________________________________ Case k k Condition k selection v1, v2 ______________________________________ k = 1 max.sub.i ≧ min.sub.i ≧ max.sub.i+1 ≧ min.sub.i+1 max.sub.i, min.sub.i+1 k = 2 max.sub.i ≧ max.sub.i+1 ≧ min.sub.i ≧ min.sub.i+1 max.sub.i, min.sub.i+1 k = 3 max.sub.i+1 ≧ max.sub.i ≧ min.sub.i ≧ min.sub.i+1 min.sub.i+1, max.sub.i+1 k = 4 max.sub.i ≧ max.sub.i+1 ≧ min.sub.i+1 ≧ min.sub.i min.sub.i, max.sub.i k = 5 max.sub.i+1 ≧ max.sub.i ≧ min.sub.i+1 ≧ min.sub.i min.sub.i, max.sub.i+1 k = 6 max.sub.i+1 ≧ min.sub.i+1 ≧ max.sub.i ≧ min.sub.i min.sub.i, max.sub.i+1 ______________________________________ and assigning e i =f*v1+*f'*v2 and e i+1 =f'*v1=f*v2 Table 2, TABLE 2 ______________________________________ Logical Case k variable f where ______________________________________ k = 1 1 k = 2 1 k = 3 DB + DA' + D = e.sub.i-1 ≧ (max.sub.i + min.sub.i)/2 A'C' A = min.sub.i - min.sub.i+1 ≧ max.sub.i+1 - max.sub.i B = max.sub.i - min.sub.i ≧ min.sub.i - min.sub.i+1 C = max.sub.i - min.sub.i ≧ max.sub.i+1 - max.sub.i k = 4 D'B + D'A' + D as above A'C' A as above B = max.sub.i+l - min.sub.i+1 ≧ max.sub.i - max.sub.i+1 C = max.sub.i+1 - min.sub.i+1 ≧ min.sub.i+1 - min.sub.i k = 5 1 k = 6 1 ______________________________________ and assigning e[i =f*v1+f'*v2 and ei+1] =f*v1+f'*v2 and e i-1 =f'*v1+f*v2.

Claim 5

Method according to claim 3, characterized in that for cases k, k=2, 1, 2, 5, and 6, the logic according to Table 3 is used for determining e i : TABLE 3 ______________________________________ Case Condition Assignment ______________________________________ k = 1 or 2 if e.sub.i-1 ≧ max.sub.i then e.sub.i = min.sub.i k = 5 or 6 if e.sub.i-1 ≧ min.sub.i then e.sub.i = max.sub.i ______________________________________

Claim 6

Apparatus in a digital oscilloscope for compacting original digital time series data comprising N data points for displaying on a display screen(3) of the digital oscilloscope of horizontal resolution M where N is a multiple of M, comprising a data acquisition memory(2), data compaction means(5), a display image memory(4) and a display screen(3), characterized in that the data compaction means(5) comprises a control unit(9), a max-min calculator(10) to determine maxima and minima of subgroups of data in the data acquisition memory(2), an auxiliary memory(11) for storing pairwise the maximum and the minimum of each subgroup, and a selector means(6) for iteratively selecting values to be stored in the display image memory(4), said control unit(3), max-min calculator(10), auxiliary memory(110 and selector means(6) being connected over a data bus(7) and a control bus(8) to each other and to the data acquisition memory(2) and the display image memory(4).

Claim 7

Apparatus in a digital oscilloscope for compacting original digital time series data comprising N data points for displaying on a display screen(3) of the digital oscilloscope of horizontal resolution M where N is a multiple of M, comprising a data acquisition memory(2), data compaction means(5), a display image memory(4) and a display screen(3), characterized in that the data compaction means(5) comprises a control unit(9), a max-min calculator(10) to determine maxima and minima of subgroups of data in the data acquisition memory(2), an auxiliary memory(11) for storing pairwise the maximum and the minimum of each subgroup, and a selector means(6) for iteratively selecting values to be stored in the display image memory(4), said control unit(3), max-min calculator(10), auxiliary memory(110 and selector means(6) being connected over a data bus(7) and a control bus(8) to each other and to the data acquisition memory(2) and the display image memory(4).

Claim 8

Apparatus according to claim 5, characterized in that the max-min calculator(10) comprises an input register(12), said input register(12) reading data from the data bus(7) and passing it to a max-calculator(13) and a min-calculator(14), the max-calculator (13) comprising a comparator(15) and a max-register(17) which is updated when the comparator(15) determines a new maximum, the min-calculator (14) comprising a comparator(16) and a min-register(18) which is updated when the comparator determines a new minimum, the max- and min-registers(17, 18) being connected to a read-out multiplexer(22) which passes the maximum and the minimum to the auxiliary memory(11).

Claim 9

Apparatus according to claim 6, characterized in that it further comprises a data counter(21) connected to two event registers(19,20) in the max- and min-comparators(13,14) in order to register for which data count the maximum and the minimum occur, the event registers(19,20) being connected to the read-out multiplexer(22) for passing the contents to second auxiliary memory.

Claim 10

Apparatus according to one of the claims 5-7, characterized in that the selector means(6) comprises logical circuits implementing the function of Table 1 and Table 2.

Claim 11

Apparatus according to one of the claims 5-7, characterized in that the selector means(6) is implemented by a microprocessor.

Claim 12

Apparatus according to claims 5, 6 or 7 characterized in that the max-min comparator(10) is implemented by a microprocessor.

Claim 13

Apparatus according to claims 5, 6 or 7 characterized in that the max-min comparator(10) is implemented by silicon technology.