Texas Instruments 2000 series, Справочное руководство

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High Performance RA-RFM RI-RFM-008B February 2002
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3. Supply voltage of the RA-RFM power stage.
The higher the supply voltage of the RA-RFM transmitter power stage (VSP
voltage), the higher the field strength which is generated by the RA-RFM assuming
that all other parameters remain unchanged. However, the generated field strength
does not increase linearly with VSP supply voltage. In addition, ferrite core
antennas show saturation effects (saturation means here that the ferrite core
cannot generate more magnetic field strength, even with a higher input current).
4. The oscillator signal pulse width.
The bigger the selected transmitter oscillator signal pulse width, the higher the
magnetic field strength which is generated by the RA-RFM, since more power is
fed into the antenna resonator by the transmitter power stage assuming that all
other parameters remain unchanged. (See Appendix 2)
The generated field strength can be measured in several ways. It may be
measured using a calibrated field strength meter or by measuring the antenna
resonance voltage using an oscilloscope and then calculating the field strength.
In summary: the generated field strength of an antenna can be adjusted with the
supply voltage VSP of the RA-RFM transmitter power stage and by selecting the
corresponding oscillator signal pulse width.
Note:
For correct adjustment of field strength according to FCC/PTT values,
especially for customized antennas, a calibrated field strength meter
must be used. Field strength measurements must be taken on a free
field test site according to VDE 0871 or equivalent regulation.