EZZE MASS2, Техническое руководство, Страница: 74 / 137

Model MASS 2 Version V_1.0
Prepared by H/W Date 22/01/2008
Subject Technical Manual Page 52/59
- Receiver Input Frequency
Mode Min Max Unit
GSM850 869 894 MHz
GSM900 925 960 MHz
DCS 1805 1880 MHz
PCS1900 1930 1990 MHz
The below table is shown LNA input impedance. So, From FEM Sawfilter to MT6120 LNA input, The
Impedance matching is need for high sensitivity. The L903, L904, L905, C910, C911, C912, C913, C916 and
C917 are the matching State.
The IF signal is then filtered and amplified through an image-rejection filter and a PGA. The multi-stage PGA is implemented
between filtering stages to control the gain of the receiver. With 2 dB gain steps, a 78 dB dynamic range of the PGA ensures a
proper signal level for demodulation. The quadrature 2
nd
mixers are provided on-chip to down convert IF signal to baseband in
an analog differential IQ format.
2. Transmitter
The MT6120 transmitter section consists of two on-chip TX VCOs, buffer amplifiers, a down-converting mixer, a
quadrature modulator, an analog phase detector and a digital phase frequency detector, each with a charge pump
output and on chip loop filter. The dividers and loop filters are used to achieve the desired IF frequency from the
down-conversion mixer and quadrature modulator. For a given transmission channel, the transmitter will select one
of the two different TX reference dividing numbers. These built-in components, along with an internal voltage
controlled oscillator and a loop filter, implement a translation loop modulator. The TX VCO output is fed to the
power amplifier. A control loop, implemented externally, is used to control the PA’s output power level.
- Transceiver Output Frequency
Mode Min Max Unit
GSM850 824 849 MHz
GSM900 880 915 MHz
DCS1800 1710 1785 MHz
PCS1900 1850 1910 MHz