Technalogix TAV-1000, Руководство пользователя

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VI-4
Signal Conditioning Components
The signal processing section of the Series IIH PCBs is used to buffer potentially noisy or damaging signals
from the ADC. Power supply voltages and forward and reflected power samples from a directional coupler
are then digitized.
Firstly, all analog signals are protected with a resettable fuse and transient voltage suppressor (TVS)
combination. These components ensure that voltages above the Vbr breakdown voltage of the TVS get
clamped and do not pass farther down the circuit. After this protection stage, the analog voltages are
dropped with voltage dividers to safe levels for the buffers and ADC. For example, a 28Vdc power supply
sample is dropped to a level below the +5Vdc supply voltage of the ADC. After the voltage dividers, the
analog signals are buffered with U7 and U8, configured as unity gain voltage followers. Finally, after some
further decoupling capacitors and filters, the analog signals get digitized by the 8-channel, 10-bit ADC (U10)
and sent to the microcontroller through a serial interface.
In the power amplifier and filter enclosures, there are (3) analog voltages that are conditioned and processed:
DC power supply sample, forward RF power, and reflected RF power. Specifically, the components for the
power amplifier and filter enclosure conditioning are as follows:
DC power supply sample – J7 (pin8), F9, D11, R32, R33, U8, C33, C34, C35, and U10.
Forward RF power – J7 (pin7), F8, D10, R30, R31, U8, C29, C30, C31, and U10.
Reflected RF power – J7 (pin6), F7, D9, R28, R29, U8, C26, C27, C28, AND U10.
In the power supply enclosure, there are (2) power supplies paralleled together. Hence, only (1) analog
voltage is conditioned and processed for the LCD. Specifically, the components for the power supply sample
are as follows:
DC power supply sample- J7 (pin8), F9, D11, R32, R33, U8, C33, C34, C35, and U10.