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MODEL M680 |
CAMAC 8-CHANNEL
TIME-TO-DIGITAL CONVERTER
  • 8-channel, 28-bit, 1-ns resolution time-to-digital converter (TDC).
  • Measures events up to 132.8 ms before or after common trigger or 0 to +256.6 ms after trigger.
  • Adjustable trigger levels and edge polarity.
  • Switchable for use in multi-hit mode.
  • Uses advanced CMOS logic for low power consumption.
  • Ultrastable, ovenized quartz crystal timebase may be checked and calibrated without removing the module form the crate.
  • Compatible with the Le Croy model 4208.
The M680 is an 8-channel time-to-digital converter (TDC) used to record the time of occurrence of eight independent electrical pulse inputs, each channel can time its event "hit" with 1-nanosecond resolution and 28-bit dynamic range. The module has provision for adjustable input logic levels, selectable edge polarity, and provisions for combining channels to perform multi-hit event measurements.

The M680 employs a highly linear time-resolution technique which requires a minimum of adjustment, is easily maintainable, and employs standard bipolar and CMOS logic elements. All optional features are switch-selectable, including the ability to select standard (24-bit) or extended (28-bit) operating modes.
M680 8-CHANNEL CAMAC TIME-TO-DIGITAL CONVERTER SPECIFICATIONS
CONFORMANCE Meets all mandatory requirements of IEEE 583-1982 CAMAC specification.
PACKAGING Single-width CAMAC module.
INPUTS
One common reference channel pulse input
Eight individual event inputs
One event veto input (for channels 1-8)
One end-of-window logic level input
One clear logic-level input.
One external clock input
INPUT LEVELS
The eight channel inputs are adjustable as a group, with signal threshold of +1.5 to -1.5 volts (appears X10 at the front panel test point). As Inputs are switchable for high-Z or 50-ohm input impedance, and are individually switchable for input polarity.
The common reference channel has a separate level adjustment +1.5 V to -1.5 V (appears X10 at the front panel test point) and is polarity switchable.
Other logic inputs are fast NIM logic levels. The external clock input is selectable as NIM level or AC coupled, requiring 0.5 V P-P min. level.
"Hit" inputs are diode-clamped for transient overload protection.
OUTPUTS Complementary, NIM-level BUSY signals are available to indicate that time interval measurements are in progress
RESOLUTION 1ns
RANGE ±223 counts (±8.388 mSec)
±227 counts (±134.208 mSec in extended mode)
Time ranges are doubled (+228 bits) in unipolar mode.
LINEARITY ±1 nanosecond
TIMEBASE Internal 125 MHz, ovenized crystal oscillator.
Accuracy is ±0.01 PPM/°C; aging < 1 PPM/year.
INDICATORS LEDs indicate CAMAC access and acquisition/readout mode status.
POWER REQUIREMENTS (MAXIMUM RATINGS)
 +6 V  3.5 A
 -6 V  1.0 A
 +24 V  180 mA
 -24 V  50 mA
Highland Technology M680 8-channel CAMAC Time-to-Digital Converter Data Sheet