User's Manual

APPLICANT: MOTOROLA EQUIPMENT TYPE: ABZ89FC3797
User / Operational Manual
Functional Description / Operation of Modules (Draft)
EXHIBIT D1-6
Specifications
The following table shows the specifications of MTR3000 Base Station / Repeater’s Receiver.
Parameter Specification
Frequency Ranges 136–174 MHz
Electronic Bandwidth Full Bandwidth
Analog Sensitivity 12 dB SINAD 0.257 μV (-118.8 dBm)
Intermodulation Rejection 85 dB
Adjacent Channel Rejection* 75 dB at 12 kHz, 80 dB at 25 kHz
Spurious and Image Response Rejection 85 dB
Intermediate Frequencies 1st: 44.85 MHz
2nd: 2.25 MHz
Intermod Rejection 85 dB
RF Impedance 50 Ω
Current Draw (Maximum) 0.05A from 14.2 VDC supply
0.5A from 10 VDC supply
0.13A from 8 VDC supply
Receiver Front End Circuitry
The RF signal enters the Receiver through a BNC-type RF connector, located on the bottom side of the Receiver.
The signal is then low-pass filtered, and the 1/2 IF and image frequency are filtered through the tunable
preselector. This signal is then amplified using a low-noise amplifier (LNA), and then further filtered to remove the
image signal.
Receiver Back End Circuitry
The signal after the image filter is then mixed down to the first IF, via a high performance (high IIP3) mixer, driven
by the low-phase noise, voltage-controlled Colpitts oscillator (VCO). The mixed-down signal then passes through
a 3-pole, crystal IF bandpass filter and an IF amplifier. The amplifier output signal passes through another 3-pole
crystal bandpass filter, and the resultant signal passes through a digital step attenuator. The desired signal is then
applied to the RF input of the custom backend Receiver IC.
Voltage Controlled Oscillator (VCO)
The Receiver Voltage Controlled Oscillator (VCO) generates a sinusoidal output signal that ranges from 180.85
MHz to 218.85 MHz. The Receive Voltage-Controlled Oscillator (RXVCO) line-up consists of four sub-circuits: a
Voltage-Controlled Oscillator (VCO), an attenuator, a buffer-amplifier, and a low pass filter (LPF).
The active device is from oscillator topology, utilizing a high-Q resonator, and four anti-parallel configured, hyper-
abrupt, tuning varactors.
The attenuator provides a broadband RF load for the VCO. The buffer-amplifier provides power leveling and
isolation. The LPF provides VCO harmonic attenuation.
Synthesizer Circuitry
The Receiver synthesizer is a subcircuit within a custom IC, which when connected with a loop filter, VCO, buffer
amplifier, lowpass filter, driver amplifier, unequal splitter, and feedback attenuator forms a phase-locked loop. The
frequency and phase of the VCO is locked to a highly-stable external Temperature Compensated Crystal Oscillator
(TCXO) reference (16.8 MHz). The custom IC contains the following integrated Phase locked loop (PLL)
components: prescaler, fractional-N divider, reference divider, phase detector, and charge-pump (for the external
loop-filter). The reference divider frequency is selected depending on the frequency band of operation, and will
range from 3.36 MHz to 16.8 MHz.