HP 54620A, User'S And Service Manual

Page: 131 / 243

The following table shows how the sampling intervals vary with sweep speed
when Auto Glitch Detect is enabled and disabled. The vernier function is off.
Table 7
Sweep Speed and Sampling Interval
Auto Glitch Detect Auto Glitch Detect Auto Glitch Detect
Enabled Disabled Enabled Disabled Enabled Disabled
Time/
Div Sample
Period Sample
Period Time/
Div Sample
Period Sample
Period Time/
Div Sample
Period Sample
Period
5 s n/a 8 ms 5 ms 40
µ
s 8
µ
s 5
µ
s 40 ns 8 ns
2 s n/a 4 ms 2 ms 16
µ
s 4
µ
s 2
µ
s 16 ns 4 ns
1 s 8 ms 1.6 ms 1 ms 8
µ
s 1.6
µ
s 1
µ
s 8 ns 2 ns
500 ms 4 ms 800
µ
s 500
µ
s 4
µ
s 800 ns 500 ns 4 ns 2 ns
200 ms 1.6 ms 400
µ
s 200
µ
s 1.6
µ
s 400 ns 200 ns 2 ns 2 ns
100 ms 800
µ
s 160
µ
s 100
µ
s 800 ns 160 ns 100 ns 2 ns 2 ns
50 ms 400
µ
s 80
µ
s 50
µ
s 400 ns 80 ns 50 ns 2 ns 2 ns
20 ms 160
µ
s 40
µ
s 20
µ
s 160 ns 40 ns 20 ns 2 ns 2 ns
10 ms 80
µ
s 16
µ
s 10
µ
s 80 ns 16 ns 10 ns 2 ns 2 ns
5 ns 2 ns 2 ns
Acquisition Memory
At sweep speeds from 1 s/div to 1
µ
s/div, the analyzer has acquisition
memory that is 16 bits wide and 2048 samples deep, and automatic glitch
detection is enabled. Part of the analyzer memory is consumed by automatic
glitch detection circuitry. When the sweep speed becomes faster than
1
µ
s/div, the glitch detection circuitry is disabled, and acquisition memory is
16 bits wide and 8192 samples deep. See “Glitch Detection” in this chapter
for more information.
Storage of Samples The following figure shows a conceptual
representation of acquisition memory. You can think of the trigger event
as dividing acquisition memory into a pre-trigger and post-trigger buffer.
The position of the trigger event in acquisition memory is defined by the
trigger reference point and the delay setting.
Ensuring Accurate Measurements
Time base and Acquisition
130