| Summary: | 碩士 === 國立交通大學 === 電信研究所 === 85 === In this report, we present a 2.4GHz ISM band power amplifier for
wireless LAN and four frequency synthesizers for CATV FDM
switching network that provides 616-676MHz, 682-742MHz,
748-808MHz and 81-100MHz frequencies band. The 2.4GHz power
amplifier is a three-stage amplifier that bias at class AB. The
first stage is a silicon BJT and the second and the third stages
are GaAs MESFET amplifiers. The P1dB of the power amplifier is
27dBm and its gain is 27dB when the input power is 0dBm. Due to
the maximum permitted harmonics/spurs of the FCC part 15.209 and
15.249, we designed a harmonic rejector to suppress the output
harmonics power. In addition, we designed a fundamental rejector
in front of the preamplifier to avoid the preamplifier
saturation at the receiving end. The size of the power amplifier
module is miniaturized to a mere 16X16.5X0.4 (mm). For precise
and stable oscillation frequency, we use VCO and PLL to compose
a frequency synthesizer. We add a buffer amplifier to the VCO
part in order to improve the load pulling effect. In addition,
we use a PLL IC ?National LMX1501A as the PLL part which can
save the circuit size. We combined the four synthesizers to a
synthesizer module using hybrid MIC technology. This synthesizer
is controlled by a Turbo C program through the RS232C interface.
The volume of each frequency synthesizer with its housing is
57X35X20 (mm). The output power is larger than 1dBm and the
phase noise of these four synthesizers are less than -90dBc/Hz
and -110dBc/Hz at 10KHz and 100KHz offset, separately.
|
|---|
