Lambda SR1 Operation Manual page 74

74 SR1 Operation Manual
samples specified in the "Dwell" control and the the pattern is shifted left by one bit. When the one/zero
is shifted out of the leftmost bit of the digital audio word it rotates back into the rightmost bit of the word.
Using the Rotating Bits generator and the Active Bits display on the Digital I/O panel is a simple
method for detecting stuck or cross-linked bits in digital audio equipment.
Digital Staircase
The Digital Staircase waveform is a special digital-only waveform which is useful for testing D/A
converters. The staircase waveform outputs 5 complete square wave cycles of the ten smallest digital
codes in succession followed by an equivalent interval of digital zero. The length of each half-cylce of a
square wave is equal to the digital audio sampling interval times the value of "Samples/Point" parameter
on the waveform panel. Thus, in the example below, each half cycle of the square wave is 100/48 kHz =
2.083 msec and therefore the time spent at each code is 5x2x2.083 msec = 20.83 msec as can be
seen in the graph.
Digital Staircase, Fs=48kHz, Sam ples/Point = 100
When observing the digital staircase using the FFT time record, be sure to enable the analyzer trigger
and set the trigger source to generator. This will ensure that the beginning of the time record is
synchronized with the beginning of the staircase.
J-Test
© 2014 Stanford Research Systems