2-3
2.2 Explanation of Each Block
2.2 Explanation of Each Block
• A01 MAIN CPU
Controls each unit and also transfers data to/from the A02 BASEBAND1, A03
BASEBAND2, A04 DEMOD DSP, and A05 MOD DSP.
• A02 BASEBAND1, A03 BASEBAND2
Generates modulation data and timing signals (e.g., symbol clock, burst gate, and
frame trigger).
• A04 DEMOD DSP
Orthogonal-demodulates the A/D-converted data (32 Ms/s), performs filtering, and
analyzes the filtered data. The DSP clock is supplied from the A12 IF.
• A05 MOD DSP
Converts modulation data to an I/Q signal; also converts the I/Q signal to burst data
through the burst gate; and performs calculation to generate an audio signal.
• A07 PANEL CONTROL
Controls the power-on/off; generates input key codes; and controls the LED indica-
tor lamps. This circuit also functions as signal routes of the DUT Interface connector
on the front panel.
• A09 RF INTERFACE
Switches the MAIN and AUX signal routes. The MAIN route has functions of TX/
RX synthesizing and dividing. This also has a power sensor to output a square wave
with an amplitude corresponding to the RF level.
• A10 CONVERTER
Provides the 1st LO (YTO) and 2nd LO (4 GHz), and frequency-converts a input
signal to the 2nd IF (106.8 MHz).
1st LO frequency = RF freq. + 4106.8 MHz (in Tester mode)
1st LO frequency = RF freq. + 4106.75 MHz (in Spectrum Analyzer mode)
In the spectrum analyzer mode, this sweeps YTO frequency.
Sets the Z1 RF ATT to set the A10 input level less than –10 dBm.
The total gain is 14 dB.
• A11 LOCAL
Consists of low-order digits and 1-MHz digit synthesizers. Frequency sweep of span
1 MHz or less is swept by the low-order digits synthesizer.
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