LeCroy 4431 Prescaler 16-Channel, ECL

CAMAC ECLine Model 4431 8-Channel, 4-Bit Programmable Prescaler

* High Density: 8 channels in a single-width CAMAC module.
* High Counting Rate: 140 MHz.
* Input/Output Levels: complementary ECL, suitable for flat twisted pair cable.
* Prescaling Factors: individually programmable via CAMAC or by front panel commands.
* Output Masking: disables undesired outputs.
* Common Inhibit: inhibits all inputs.
* Common Test: permits testing of all enabled channels.
* Common Reset: resets all channels.
* OR Output: logical OR of all 8 outputs.

The LeCroy Model 4431 is a programmable prescaler designed especially to extend the max- imum working frequency of either the Models 4432 and 4434 32-channel, 24-bit Latching Scalers or the Model 4433 32-channel, 16-bit Latching Scaler.

The prescaling factors are individually programmable under either CAMAC or front panel control and may be monitored via dataway read commands. The input to output transit time is indepen- dent of the prescaling factor, making the 4431 very useful in altering trigger logic rates without timing readjustment. Individual output widths are continuously adjustable in the range 4-20 nsec via front panel potentiometers. A mask register may be used to disable individual channel out- puts and is programmable by either CAMAC commands or front panel switches. In the CAMAC mode, the status of the mask is displayed by panel mounted LED'S. In addition to the individual outputs, the 4431 also generates an OR output whose output duration is equal to the time overlap of the channel outputs.

Front panel inputs allow for external test, reset, and inhibit of the unit. Eight line twisted pair con- nectors are used for signal input/output and employ complementary ECL levels which are fully compatible with all ECLine modules.

SPECIFICATIONS CAMAC Model 4431 8-CHANNEL, 4-BIT PROGRAMMABLE PRESCALER

INPUT CHARACTERISTICS

Signal Inputs:

8, in a 2x 8 pin front panel connector; accepts differential ECL input levels; 110 Ohm input impedance pin to pin; direct coupled. Minimum input pulse width: 4 nsec; maximum input frequency: 140 MHz.

Test Inputs:

1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; triggers all 8 channels at once. Minimum input pulse width: 4 nsec; max- imum input frequency: 140 MHz.

Reset Inputs:

1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; resets all 8 prescalers (loads PRESC FACTOR). Minimum input pulse width: 6 nsec.

Inhibit Inputs:

1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; inhibits all 8 channel outputs for the duration of the signal.

OUTPUT CHARACTERISTICS

Signal Output:

8, in a 2 x 8 pin front panel connector; complementary ECL levels. Width: front panel adjustable from <4 to >20 nsec for each channel; updating outputs. Output width stability: +/- (0.5 nsec + 0.5% width).

OR Output:

1, in a 2 x 1 pin front panel connector; complementary ECL levels. OR output equals the logical OR of all 8 channel outputs.

CAMAC COMMANDS AND FUNCTIONS (remote mode)

C:

Resets all 8 prescalers (Loads PRESC FACTOR) at S2 (equivalent to front panel RESET input).

Z:

Initialize the unit, i.e., clears mask register and resets all prescaling factors to 16 at S2.

X:

X = 1 response is generated for any of the following functions.

Q:

Q = 1 response is generated for any of the following functions only if the unit is set to remote mode.

N-F(O)-A(O) to A(8):

Read the mask register onto R 1 -R8.

N-F(1)-A(O) to A(8):

Read the prescaling factor of the addressed channel A(O) to A(8) onto Rl-R4.

N-F(9)-A(O) to A(8):

Reset all prescalers (loads PRESC FACTOR) at S2 (equivalent to front panel reset input).

N-F(16)-A(O) to A(8):

Write the mask register, data on Wl-W8. A "l " on a write line inhibits the corresponding channel.

N-F(1 7)-A(O) to A(8):

Write the prescaling factor of the addressed channel A(O) to A(8); data on Wl-W4. Prescaling factor = data+ 1.

FRONT PANEL SWITCHES AND LED'S

Local Switch (1):

Select the 4431 operating mode. When set in local mode, all CAMAC functions are disabled and the front panel switches are enabled.

Local Led (1):

When ON, it indicates LOCAL operation.

Mask Switch (1):

Selects MASK or PRESC FACTOR control (only in local mode).

Data Switches (8):

a. MASKmode: 8 data switches (1, 2, 3, 4, 5, 6, 7, 8) select mask pattern (only in local mode). A "l inhibits the corresponding channel.

b. PRESC FACTOR mode: 4 data switches (1, 2, 4, 8) select prescaling factor (1 -1 6) 3 data switches (1, 2, 4,) select channel address (1-8) (only in local mode).

Data LED's (8):

a. MASK mode: 8 LED's display the current mask register state (always in remote mode!).

b. PRESC FACTOR mode: 4 LED's display the current prescaling factor of the channel selected by the 3 data switches (1, 2, 4) (only in local mode).

Store Push Button (1):

a. MASK mode: Writes the selected (8 data switches) mask pattern into the mask register.

b. PRESC FACTOR mode: Write the selected (4 data switches) prescaling factor into the selected (3 data switches) channel. All prescalers are loaded with the PRESC FACTOR

GENERAL

Double Pulse Resolution

< 7 nsec

Input to Output Transit Time:

14+/- 2 nsec; independent from the prescaling factor.

Packaging:

RF-shielded single width CAMAC module.

Power Consumption:

+ 6V<3OOmA
- 6V< 2.2A
-24V< 7OmA

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INPUT CHARACTERISTICS
Signal Inputs:	8, in a 2x 8 pin front panel connector; accepts differential ECL input levels; 110 Ohm input impedance pin to pin; direct coupled. Minimum input pulse width: 4 nsec; maximum input frequency: 140 MHz.
Test Inputs:	1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; triggers all 8 channels at once. Minimum input pulse width: 4 nsec; max- imum input frequency: 140 MHz.
Reset Inputs:	1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; resets all 8 prescalers (loads PRESC FACTOR). Minimum input pulse width: 6 nsec.
Inhibit Inputs:	1, in a 2x 1 pin front panel connector; accepts differential ECL input levels; 1 10 Ohm input impedance pin to pin; direct coupled; inhibits all 8 channel outputs for the duration of the signal.
OUTPUT CHARACTERISTICS
Signal Output:	8, in a 2 x 8 pin front panel connector; complementary ECL levels. Width: front panel adjustable from <4 to >20 nsec for each channel; updating outputs. Output width stability: +/- (0.5 nsec + 0.5% width).
OR Output:	1, in a 2 x 1 pin front panel connector; complementary ECL levels. OR output equals the logical OR of all 8 channel outputs.
CAMAC COMMANDS AND FUNCTIONS (remote mode)
C:	Resets all 8 prescalers (Loads PRESC FACTOR) at S2 (equivalent to front panel RESET input).
Z:	Initialize the unit, i.e., clears mask register and resets all prescaling factors to 16 at S2.
X:	X = 1 response is generated for any of the following functions.
Q:	Q = 1 response is generated for any of the following functions only if the unit is set to remote mode.
N-F(O)-A(O) to A(8):	Read the mask register onto R 1 -R8.
N-F(1)-A(O) to A(8):	Read the prescaling factor of the addressed channel A(O) to A(8) onto Rl-R4.
N-F(9)-A(O) to A(8):	Reset all prescalers (loads PRESC FACTOR) at S2 (equivalent to front panel reset input).
N-F(16)-A(O) to A(8):	Write the mask register, data on Wl-W8. A "l " on a write line inhibits the corresponding channel.
N-F(1 7)-A(O) to A(8):	Write the prescaling factor of the addressed channel A(O) to A(8); data on Wl-W4. Prescaling factor = data+ 1.
FRONT PANEL SWITCHES AND LED'S
Local Switch (1):	Select the 4431 operating mode. When set in local mode, all CAMAC functions are disabled and the front panel switches are enabled.
Local Led (1):	When ON, it indicates LOCAL operation.
Mask Switch (1):	Selects MASK or PRESC FACTOR control (only in local mode).
Data Switches (8):	a. MASKmode: 8 data switches (1, 2, 3, 4, 5, 6, 7, 8) select mask pattern (only in local mode). A "l inhibits the corresponding channel. b. PRESC FACTOR mode: 4 data switches (1, 2, 4, 8) select prescaling factor (1 -1 6) 3 data switches (1, 2, 4,) select channel address (1-8) (only in local mode).
Data LED's (8):	a. MASK mode: 8 LED's display the current mask register state (always in remote mode!). b. PRESC FACTOR mode: 4 LED's display the current prescaling factor of the channel selected by the 3 data switches (1, 2, 4) (only in local mode).
Store Push Button (1):	a. MASK mode: Writes the selected (8 data switches) mask pattern into the mask register. b. PRESC FACTOR mode: Write the selected (4 data switches) prescaling factor into the selected (3 data switches) channel. All prescalers are loaded with the PRESC FACTOR
GENERAL
Double Pulse Resolution	< 7 nsec
Input to Output Transit Time:	14+/- 2 nsec; independent from the prescaling factor.
Packaging:	RF-shielded single width CAMAC module.
Power Consumption:	+ 6V<3OOmA - 6V< 2.2A -24V< 7OmA