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ampmode (P) - set the amplifier mode 'continuous' or 'pulsed'
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  ampmode - sets the amplifier mode 'continuous' or 'pulsed'. this 
    'current' parameter is a string whose entries are the characters
    'd','p' and 'c' with no separation. The number of characters must
     equal the number of channels, numrfch. The characters from left
     to right refer to the transmitter channels "1","2","3" ...etc, 
     which for VNMRS correspond to preamps or RF cable outputs from the
     Front End and from the transmitters in the RF cardcage, right to 
     left. Set: 'd' default, 'p' for pulsed and 'c' for continuous. 
     ampmode must be set on the command line. 

  If ampmode does not exist the default is 'd' for each channel and for 
  most experiments all channels can be set to 'd'. 

  Examples: 

     ampmode = 'dddd' with numrfch = 4 sets "pulsed" "mode" on the observe
     channel and "continuous" mode on all other channels. 

     ampmode ='ddp' with numrfch = 3 forces pulsed mode on channel "3" 
     whether or not it is an Observe or Decoupler channel.

  The parameter ampmode affects all amplifiers except the High-Power Proton
  RF Amplifier, whose mode is controlled by a switch on the front panel. The
  driver of the High-Power Proton RF Amplifier is controlled by ampmode. 

  In "pulsed" mode an amplifier can be blanked on and off during the pulse 
  sequence.  In "continuous" mode the amplifier is always on. In "default"
  mode an amplifier is in "pulsed' mode if the channel is used for Observe 
  and is in continuous mode if the channel is used as a Decoupler. The 
  purpose of amplifier blanking is to reduce injected into the receiver and 
  in some experiments to prevent the "tickling" of the NMR spin system with 
  low level noise. If tickling is not an issue, decoupler channels generally 
  have filters to remove the noise and can remain in continuous mode.  

  For the High-Power Proton RF Amplifier "pulsed" = "GATE ACTIVE" and 
  "continuous" = "CLASS AB".  Both ampmode and the switch must be set because
  the driver is controlled by ampmode. If the High-Power Proton RF Amplifier
  is used in "CLASS C" mode the driver should be in continuous mode.

  All amplifiers are put in pulse mode and blanked if an experiment ends 
  with "abort acquisition", "aa" or "stop".  A special "noblank" mode is
  provided for Solids NMR for which amplifiers are put in "continuous" 
  mode and left unblanked.  The choice of modes between experiments affects
  the temperature of the amplifier and its amplitude and phase stability.
  "almost always on" is best for Solids NMR and "almost always off" is best
  for other experiments. 

  For Solids experiments the amplifiers are unblanked throughout except 
  during acquisiton. For three-channel Solids experiments the amplifier 
  assigned to dec2 can be put in "pulsed" mode to reduce injected
  noise. If this is done a bandpass filter may not be needed on the dec2 
  output. This capability is unique to the Solids sequences. 
  




  The parameter hipwrampenable affects only those channels whose amplifiers 
  are controlled by a High/Low Power Relay Panel. Relay Panels are found on
  systems that require low power for Liquids NMR and high power for Solids 
  NMR. They are usually located in the same bays that contain the high-power 
  amplifiers.

  For high-band channels the High-Power Proton RF Amplifier is driven by the 
  standard 50-Watt amplifier "A" in the standard left bay. In high-power
  mode the output of the driver is directed through the High-Power Proton RF
  Amplifier to the Front End to produce up to 800 to 1000 Watts. In low-power 
  mode the output of the 50-Watt Amplifier "A" goes directly to the Front End. 

  For low-band channels a High-Power 6-200 MHz or 10-130 MHz Amplifier replaces 
  the standard 300-Watt Amplifier "B" in the standard left bay. In high-power
  mode the Relay attenuates the input of the Amplifier so that its output is 
  about 1000 Watts.  In low-power mode the Relay attenuates the input of the 
  Amplifier so that its output is a maximum of 300 Watts.

  Create hipwrampenable on the commandline with: 

     create('hipwrampenable','string','global')

  If hipwrampenable is not present the default is 'n' for all channels. 
 








 
  
  preAmpConfig - sets the band of the preamp, high or low, connected to 
     each transmitter channel. This global parameter is a string whose 
     entries are the characters "H" "L" and"X" separated by commas.  The 
     number of characters must equal the number of channels, numrfch. The 
     characters from left to right refer to the transmitter channels
     "1","2","3".. etc, which for VNMRS correspond to preamps or RF cable 
     outputs from the Front End and fom the transmitters in the RF card 
     cage, right to left. Set: 'H' for a highband preamp, 'L' for a 
     lowband preamp and 'X' for no preamp. 
   
  nm1 - returns the transmitter corresponding to the nucleus in argument 
     1. nm1 is used to set the channel number for obs, dec, dec2 and dec3 
     on the Channels screen of the Acquisition Page. If probeConnect and 
     preAmpConfig are present they are used. Otherwise if rfchannel is
     present,it is used or if rfchannel is not present the defaults are set. 

  probeConnect and preAmpConfig are required for all experiments that use 
  transmitters "3" and "4" as Obs or Dec.   Create probeConnect and 
  preAmpConfig as global parameterson the commandline with: 

     create('probeConnect','string','global')
     create('preAmpConfig','string','global')

  If probeConnect is present it will overide the transmitter settings in 
  the 'current' parameter rfchannel. 

  If probeConnect and preAmpconfig are not created and rfchannel is not
  present the default transmitters are: 

     Obs (highband) "1" Dec (lowband) "2" 
     Obs (lowband) "2"  Dec (highband "1" 
     Dec2 (highband or lowband) "3"
     Dec3 (highband or lowband) "4" 

  If probeConnect and preAmpconfig are not created the default preamps are
  presumed to be:

     "1" highband 
     "2" lowband
     "3" lowband 
     "4" lowband 

  probeConnect and preAmpConfig must both exist or both be absent. 
  If they exist both must have correct values.  An empty string or incorrect
  string in either parameter will cause errors in channel selection. 

  Examples: 

  ProbeConnect = 'H1 C13 F19 N15', PreAmpConfig = 'HLHL', numrfch = 4,
  tn = 'H1', dn = 'C13', dn2 = 'N15' causes: 

      Obs on channel "1"
      Dec on channel "2" 
      Dec2 on channel "4"

  ProbeConnect = 'H1 N15 F19 C13', PreAmpConfig = 'HLHL', numrfch = 4, 
  tn = 'H1', dn = 'C13', dn2 = 'N15' causes: 

      Obs on channel "1"
      Dec on channel "4" 
      Dec2 on channel "2"

  ProbeConnect = 'H1 N15 F19 C13', PreAmpConfig = 'HLHL', numrfch = 4, 
  tn = 'C13',dn = 'H1', dn2 = 'N15' causes: 

      Obs on channel "2"            
      Dec on channel "1"
      Dec2 on channel "4"

  


      



  


