RIGOL DS1000B User Manual
Page 89
RIGOL
Programming Guide for DS1000B Series
2-77
Peak Detect
1. Conditions
(1) The Peak Detect acquisition mode is open
(2) Time base is greater than 1 us
The acquisition is not Peak Detect in other conditions.
2. Data storage format in memory under Peak Detect
The waveform data in Peak Detect mode are stored in the form of max1-min1,
max2-min2, max3-min3. That is, a waveform point has a couple of data: a max and a min,
which are stored alternately. As the following figure shown, the waveform display will be
serrated.
3. Pick up waveform point of specific time:
(1) CntSpan = (-Time+TrigOffset)*SaRate //The sample points of specific time
(2) CntSpan = CntSpan*2
// Every time contains two data
(3) DstPtr = MidPt – CntSpan // Index of waveform point of specific time
Example: To calculate the index position at -7.69ms point when sample rate is 250k
Sa/s and trigger offset is 500 us.
CntSpan = (7.69+0.5)*250=1922+125=2047 //The sample points of specific time
CntSpan = 2047*2 = 4094
// Every time contains two data
DstPtr = 4096 – 4094=2 // Index of waveform point of specific time
Then, you will get two waveform points of this time: Memory(2) and Memory(3).
4. Time calculation of specific index point:
Known condition: memory index point “ind”
(1) TimeSpan = (ind – MidPt)/(SaRate*2)
//Take half of the result since every time