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# FMC Delay 1ns 8cha
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# Preliminary functional system specifications
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- 1 ns resolution or better.
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- Accuracy: */- (500 ps* timebase accuracy).
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- Timebase accuracy: +/- 4ppm.
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- Implementation details: timebase from a local TCXO on FMC card
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and needs calibration. The 4ppm accuracy will only be reached
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when used on a White Rabbit enabled FMC carrier.
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- 200 ns - 120 s range or better.
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- 1 input, selectable between front panel and FMC connector. This
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input is shared by all output channels.
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- Input electrical standard will be TTL, with optional 50 Ohm
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termination. The default power-up state is high impedance. A LED
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- Input electrical standard will be TTL (not LVTTL), with optional 50
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Ohm termination. The default power-up state is high impedance. A LED
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will signal termination status.
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- External input needs to be protected against +15V pulses with a
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pulse width of at least 10us @ 50Hz (with protection diodes if
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- Output standard: 50 Ohm TTL drivers (with 2V/ns or faster rising
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edges). At power-up the default output state is low, with no
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glitches.
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- SMC connectors for input and outputs. LEMO variant should also be
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explored if mechanically possible.
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- SMC connectors for input and outputs.
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- 4 individually controllable outputs, with independent delay, width
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and enable/disable.
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- Delay circuit reacts on input rising edge. Minimum input pulse
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width: 100 ns.
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width: 100 ns. Pulses shorter than 20ns should be ignored.
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- Input pulses will be ignored until the longest programmed delay of
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the previous input pulse has expired.
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- Output pulse width is programmable in steps of system clock ticks
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(~125 MHz) with a 16-bit register per output channel.
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- Jitter will be measured by probing two output channels which have
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FPGA and fine delay chips at the outputs. To be considered for
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improving jitter: monolithic FFs in the FMC, before the fine delay
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chips. Continuous calibration of fine delay chips might be needed to
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compensate for Process-Voltage-Temperature (PVT) effects.
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compensate for Process-Voltage-Temperature (PVT) effects. The
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timebase is from a local TCXO on FMC card and needs calibration. The
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4ppm accuracy will only be reached when used on a White Rabbit
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enabled FMC carrier.
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-----
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... | ... | @@ -73,12 +82,12 @@ |
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</tr>
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<tr class="even">
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<td>15-06-2010</td>
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<td>Date reserved for Final functional specification review meeting.</td>
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<td>Final functional specification review meeting held. Resulted in minor modifications.</td>
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</tr>
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</tbody>
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</table>
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-----
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Erik van der Bij - 11 June 2010
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Erik van der Bij - 15 June 2010
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