User manual

MAUI Oscilloscopes Remote Control and Automation Manual
RIS Waveforms
These are composed of many acquisitions interleaved together. The descriptor parameter, RIS_SWEEPS,
gives the number of acquisitions. The ith point belongs to the mth segment where:
m = i modulo (RIS_SWEEPS)
Has a value between 0 and RIS_SWEEPS -1.
Then with:
j = i - m
x[i] = x[j,m] = HORIZ_INTERVAL * j + RIS_OFFSET[m]
where the RIS_OFFSET can be found in the RISTIME array. There can be up to 100 eight-byte double
precision floating point numbers in this block. The instrument tries to acquire segments such that:
RIS_OFFSET[i] ≈ PIXEL_OFFSET + (i - 0.5) * HORIZ_INTERVAL
Decoding Floating Point Numbers
Single precision values are held in four bytes. If these are arranged in decreasing value order, we get the
following bits:
bit 31, bit 30, bit 29, bit 28 . . . . . bit 3, bit 2, bit 1, bit 0
Note: If the byte order command CORD is set for low byte first, the bytes as received in a
waveform descriptor are received in reverse order. However, within a byte the bits keep their
order, highest at the left, as expected.
From these bits we are to construct three numbers that are to be multiplied, S x E x F:
S = (-1)
s
E = 2
(e - 127)
F = 1 + f
S, E, and F are calculated directly from the 32 bits. The following diagram illustrates the calculation of the
vertical gain example:
5-24