Transcript PS TFB Hardware: J. Belleman, A. Blas, T. Bohl, F. Caspers

New PSB Beam Control
Upgrade of daughter cards
1.
Generation of REV clocks
2.
Synchronization with Linac 4
3.
Hardware and firmware upgrades
Alfred Blas
PSB rf Working group meeting 24/03/2009
1
Generation of rev clocks
Required:
What For?
Specifications:
Div.+
Dbl Tag
fMDDS
1 GHz
DDS
Clock signal at a high harmonic of the revolution
TFB, 1TFB, Q measurement, ….
up to 150 MHz, non-tagged, fixed harmonic
< 160 MHz
Clock
Freq. Div.
+ Tagging
hLO
< 160 MHz
Tagged Clock
Freq./2
< 80 MHz
Clk
-> 50 % Duty
Cycle
NCO
< 20 MHz rf
Present rf creation setup
SDDS
Alfred Blas
PSB rf Working group meeting 24/03/2009
2
Generation of rev clocks
The present rf creation circuit with a MDDS in cascade with a SDDS
limits the output frequency to 20 MHz
The creation of a high rev harmonic clock means using either:
1.
A dedicated MDDS programmed to output a non-tagged clock
2.
A dedicated SDDS channel + an external PLL
3.
Using the second output on the MDDS to supply a non tagged < 80 MHz (or < 160
MHz) clock. 80 MHz at 1.4 GeV in the PSB would mean 28 MHz at 50 MeV and thus
a bandwidth of the targeted digital circuit < 9 MHz. This is not sufficient. If the MDDS
frequency was limited to 150 MHz, then the targeted circuits could cope with it (they
are not yet designed, but this is the what ADCs can achieve with 14/16bit nowadays).
In terms of flexibility and absence of new development, the dedicated
MDDS solution 1) is preferred.
Then comes solution 2) which means the creation of a specific PLL circuit
and the use of a dedicated SDDS channel.
The lastly chosen solution is 3) which requires some compromises (it is the
less flexible).
Alfred Blas
PSB rf Working group meeting 24/03/2009
3
Synchronization with Linac 4
Source
Pre-chopper
+LEBT
Energy
modulation
Debuncher
Distri
4*rf
Linac 4
180 m
45 keV
Chopper
ON/OFF
To Linac rf
feed-forward
Number of turns
+ VH1
Voltage modulation
Phase modulation
Linac rf
Injection
Sequencing
control
(IN BOR)
Timing
CO
Rev + 10* REV
Inj. Ref
Source
ΔE 4
rings
4 timing values for each
injected turn
Alfred Blas
BIXi.SDIS
BIXi.SInjChop
BIXi.SInjRF
Inj. rf reference (h1 or h2)
Application
PSB rf Working group meeting 24/03/2009
4
Synchronization with Linac 4
Injection Reference source
The injection reference rf could be issued from the R1 LLRF (last ring that will stay at a fixed
frequency until it comes to its turn), but there is not much to gain using this approach. The
economy of one extra rf source would be obtained at the price of having R1 treated as a special
case with no injection synchronization and a specific treatment within the injection sequencing
control (ISC) because the injection in ring 1 would become the only case where the reference
train could be used without applying the phase advance corresponding to the accelerating law
Alfred Blas
PSB rf Working group meeting 24/03/2009
5
Hardware and firmware Upgrades
DDC: The following changes require a new FPGA
1.
Add 2 LOs
2.
Add the signal monitoring circuit
3.
Add FIR filters (?)
4.
Add a couple of LEDs (Clock OK, …)
SDDS: The following changes require a new FPGA
1.
Add the I/Q pre-programmed modulation circuits
2.
Add a circuit that changes progressively each LO harmonic from one value to another (2 new registers:
final h; number of clock tics for the ramping process + 1 control start bit)
3.
Add the signal monitoring circuit
4.
Add a couple of LEDs (Clock OK, …)
MDDS: The following changes don’t require a new FPGA
1.
Make the tagging externally
Alfred Blas
PSB rf Working group meeting 24/03/2009
6
Hardware and firmware Upgrades
General:
1.
1394b connector -> eSATA 3 Gb/s(?)
This change required for a better mechanical reliability would mean to adapt all daughter cards + Fan-out.
Because the eSATA connector is wider (21mm instead of 12 mm), this connector change would mean:
•
On the MMDS: remove 2 SMC connectors (the 1 GHz in and out that have to be connected together)
•
On the SDDS and DDC: remove the external reset input that is not used
Alfred Blas
PSB rf Working group meeting 24/03/2009
7