Mt<n> — Transmit sequence #n

Triggers

Trigger parameters list the starting times (in microseconds relative to range zero), the lengths (in microseconds), and the active sense of each trigger generated by the internal trigger generator.

Set a length to 0 to inhibit the trigger on that line.

The Start time can include an additional term consisting of the formula: pulse period x a fractional multiplier between -1.0 ... +1.0. This allows you to produce trigger patterns that would not otherwise be possible, for example, a trigger that occurs half way between every pair of transmitted pulses, and remains correctly positioned regardless of changes in the PRF. If you do not want to use this term, enter this multiplier as 0, so the term will be omitted from the printout.

In the following example, Trigger #2 is a 10.0 μsec active–high pulse with a leading edge that occurs precisely halfway between the zero–range of every pair of pulses. Similarly, Trigger #6 is a 2.0 μsec active–low pulse with a falling edge that is nominally 5.0 μsec prior to range zero, but that is advanced by 1.0 μsec for every millisecond of trigger period. All other triggers behave normally, and have fixed starting times that do not vary with the trigger period.

Trigger #1 
   Start : 0.000000  usec 
   Length : 1.00  usec 
   Pull up : YES
Trigger #2
  Start:  0.00  usec + ( 0.500000 * PRT ) 
  Length:  10.00 usec
  Pull up:YES
Trigger #3 
  Start:  -3.00 usec 
  Length:  1.00  usec 
  Pull up: YES
Trigger #4  Start:  -2.00 usec 
        #4  Length:  1.00  usec
       Pull up :YES
Trigger #5  Start:  -1.00 usec 
        #5  Length:  1.00  usec
       Pull up:YES
Trigger #6  Start:  -5.00 usec + (-0.001000 * PRT ) 
        #6  Length:  2.00  usec     
        Pull up:NO

Note the following about these variable start times:

• The PRT multipliers can only be used with the RVP10 internal trigger generator. The PRT–relative start times are completely disabled when an external trigger source is chosen from the Mt menu.
• When PRT–relative triggers are plotted by the Pb command, the active portion of the trigger is drawn cross–hatched at a location computed according to the current PRF. The cross–hatching serves as a reminder that the location of that trigger may vary from its presently plotted position.
• The PRT multiplier for a given pulse is applied to the interval of time between that pulse and the next one.

  This distinction is important when RVP10 generates multiple–PRT triggers, for example, during DPRT mode or during dual–PRF processing.

  Multipliers from 0.0 ... +1.0 are generally safe to use because they shift the trigger into the same pulse period that originally defined it. For example, a start time of (0.0 μsec + (0.98 * PRT)) positions a trigger 98% of the way up to the next range zero. But, if -0.98 were used, and if the period of the previous pulse was shorter than the current one, then that shorter period would become incorrect (longer) as a result of having to fit in the very early trigger.

In some situations, waveforms that do not fit are zeroed (not output) to preserve the desired period. This means that you can define triggers with large positive start times, and they come into existence only when the PRF is low enough to accommodate them. It applies when:

• The trigger period is internally determined, that is, the external pretrigger input is not being used.
• The overall span of the six trigger definitions combined does not fit into that period.

For example, if Trigger #2 is defined as a 200.0 μsec pulse starting at +400.0 μsec:

• The trigger is suppressed if the PRF is 2000 Hz.
• The trigger is present at a PRF of 1000 Hz.

• If a trigger does not completely fit within the overall period it is suppressed.

This means that although the +400.0 μsec start time is still valid at 2000 Hz, the entire 200.0 μsec pulse would not fit, and the pulse is eliminated.

Start limits: -5000 ... 5000 μsec

Width limits: 0 ... 5000 μsec

Pulses

Pulse
Pulse ID: "mw_X", X = 0

The Pulse ID defines which matching filter (that has been defined in the ‘mw<n>’ menus) is appropriate to use in this transmit sequence.

Burst Freq Estimator (fraction of FIR filter) - Start: 0.10 , Lenght: 0.35

This question defines the location of the aperture window which is the narrowed set of samples used for AFC frequency estimation This estimator is mostly used with the Pb (plotting commands). See Pb subcommands.