58 (327) BRUKER BIOSPIN User Manual Version 002
Basic Setup Procedures
channel define the precise irradiation frequency by setting the nucleus and the off-
set O1 from the basic frequency. In this example, we want to set up for pulsing/ob-
serve on the nucleus
79
Br. Selecting
79
Br for channel F1 defines the basic
frequency BF1 of
79
Br (in this case on a 600 MHz spectrometer, 150.360709) and
the adjustable offset (9000 Hz in this case). Both values are added to show the
actual frequency setting, SFO1. The frequency setting is taken from a nucleus ta
-
ble which is calculated for the respective magnetic field B
0
. The index 1 in O1,
BF1, and SFO1 refers to the RF channel 1 (which is also found in the pulse pro
-
gram where the pulse is defined as p1:f1. Note that this index does not exist for
the following columns which represent the hardware components (SGU1-4 refers
to the slot position in the AQS-rack). The lines connecting the (software) channel
F1 to the actual frequency generation and amplification hardware can be drawn
ad libitum as long as the required hardware connections are present. The connec
-
tions between transmitter and preamp cannot be routed arbitrarily, because every
transmitter output is hardwired to a preamplifier, so the lines are drawn in green.
Please note that the nucleus in channel F1 is always the observe nucleus.
To set up for
79
Br observation, click on Default and the correct routing will be
shown.
The green dot between SGU1 and amplifier 1 indicates that for this nucleus in this
connection, the transmitter has been calibrated for amplitude and phase linearity
(CORTAB).
For example, if you select a nucleus where this has not been calibrated and the
green dot is not visible, the same power level setting in dB will produce >6 dB
more power (> 4-fold power) which may destroy your probe. Calibrate power lev
-
els in such a case starting with 10 dB less power (higher pl(n)-value) to prevent
destruction of your probe!
The connections between SGU(n) and transmitter (n) can be altered by clicking
on either side of the connecting line (removes the connection), and clicking again
on both units you want to connect (route). In case of high power transmitters, you
have two power stages which you select by clicking on the desired stage. High
power stages require the parameter powmod to be set to “high”. Selecting a path
which is not fully routed will generate an error message.
To leave the display, click on Save. Make sure your probe X-channel is connected
to the selected preamplifier (the sequence of preamplifiers in edasp represents
the physical position of the preamplifier in the stack). If the preamp is a high power
type, make sure the correct matching box is inserted into the preamp (for 500-800
MHz systems, it would be labelled for the frequency range 120-205 MHz). Con
-
nections are shown in the figure below:
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