BNC 745-T, User Manual

Page: 19 / 35

Timing principle using Burst mode
Each Channel can be independently set to Burst mode. In the following example Burst trigger has
been set to IN1, Burst pulse number to 5 and Burst period to TB
Figure - 15. Burst Mode Timing
The minimal burst period value is 1000ns. But it has to be noticed that this value depends on the
Burst trigger period value and on the Burst pulse number.
𝑇𝑇𝑇𝑇𝑇𝑇𝑀𝑀𝑇𝑇 =
𝑇𝑇
𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡
𝑇𝑇𝑀𝑀𝑇𝑇
𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝑁𝑁𝑁𝑁𝑁𝑁
So, to get a TBmin = 1000ns we can configure the device as follows:
•
Pulse nbr max = 5
•
T
trigger
min = 5000ns
As depicted on Figure - 15, in the case of a generation of pulse train (Burst Mode) on a channel, the
Gate In signal can allow some pulses among the pulse train.
It has to be noticed that when a delay D is specified on a channel using Burst mode as trigger mode,
the MODEL 745-T manages the delay generation according to that rule:
- If delay 𝐷𝐷 > 𝑇𝑇𝑇𝑇 − 15 𝑇𝑇𝑃𝑃 , the delay generation is shared between the delay register specific
to the channel ( 𝐷𝐷
𝑐𝑐ℎ𝑎𝑎𝑎𝑎
= 𝑇𝑇𝑇𝑇 − 15 𝑇𝑇𝑃𝑃 ) and the delay register associated to the burst trigger
generation ( 𝐷𝐷
𝐵𝐵𝐵𝐵𝐵𝐵
= 𝐷𝐷 − 𝑇𝑇𝑇𝑇 + 15 𝑇𝑇𝑃𝑃 ).
- If delay
𝐷𝐷 ≤ 𝑇𝑇𝑇𝑇 − 15 𝑇𝑇𝑃𝑃
, the delay generation is managed as usual, that is to say by using the
selected channel delay register.
To summarize: 𝐷𝐷 = 𝐷𝐷
𝑐𝑐ℎ𝑎𝑎𝑎𝑎
+ 𝐷𝐷
𝐵𝐵𝐵𝐵𝐵𝐵
when 𝐷𝐷 > 𝑇𝑇𝑇𝑇 − 15 𝑇𝑇𝑃𝑃 .
When several channels are using Burst mode as trigger mode and one of the delay specified leads to
the 𝐷𝐷
𝐵𝐵𝐵𝐵𝐵𝐵
register use ( 𝐷𝐷 > 𝑇𝑇𝑇𝑇 − 15 𝑇𝑇𝑃𝑃 ), the 𝐷𝐷
𝐵𝐵𝐵𝐵𝐵𝐵
value will be ignored (each channel will be delayed
by 𝐷𝐷
𝐵𝐵𝐵𝐵𝐵𝐵
).
3/2/18
Berkeley Nucleonics Corporation, 2955 Kerner Blvd. San Rafael, CA 94901
Info@berkeleynucleonics.com, Call 800-234-7858 or Live-Chat @ www.berkeleynucleonics.com
19 of 35