Appeal No. 2005-2572
Application No. 10/268,809
illustrated in Figure 5. The following passage describes this
embodiment in conjunction with the embodiment shown in Figure 4:
FIG. 4 shows an embodiment involving
wireless control of the modulation unit 12.
Therein, a receiver resonant circuit 31 is
provided which is formed by a parallel
connection of a coil 21 and a capacitor 22,
said receiver resonant circuit serving to
receive an RF control signal 28 emitted by a
transmitter unit 27. The resonant circuit 31
is tuned to the frequency of the RF control
signal 28; this frequency lies in a frequency
range other than that of the Larmor frequency
and that of the resonance frequency of the
resonant circuit 20 in order to avoid mutual
interference. The RF control signal 28 has a
squarewave envelope as shown. In this
embodiment the resonant circuit 20 is formed
by a parallel connection of the coil 11 and a
capacitor 19.
The modulation unit 12 connected to the
resonant circuit 31 in this case includes a
field effect transistor 26 whose gate G
carries a gate voltage 30 which periodically
switches the transistor 26 to the low-ohmic
state and the high-ohmic state. Using a
diode 23, connected to the resonant circuit
31, and a parallel connection of a capacitor
24 and a resistor 25, the gate voltage 30 is
derived from the RF control signal 28 which
is received by the resonant circuit 31.
Because of the periodic switching over of the
transistor 26, the desired modulation is
imposed on the resonant circuit 20, the
modulation frequency being adjustable by way
of the frequency of the squarewave envelope
of the RF control signal 28.
. . .
FIG. 5 shows an embodiment which
includes an optical control lead 36
between the control unit 13 and the
6
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Last modified: November 3, 2007