5 - 16 HS70A Service Manual
• AD converter 8 (ADS5282, 8CH)
• BF ASIC 4 (MCB124,16CH)
• RX Dynamic Aperture
• RX Apodization
• BFIC controlling
• Synthetic Aperture
• Trapezoidal imaging
• Multi-line receiving
• TX Focal point
▐ Operational Principles
TX Pulser
Exciting pulse data provided by the BF ASIC (MCB124) go through the TX Pulse Buffer and
are provided to the TX Pulse (MAX4811). The TX Pulser uses the high voltage and Exciting
pulse data provided by the DC-DC Module to generate Bipolar Pulser. Bipolar Pulser uses
PSA (Probe Select Assembly) to send to the Probe Element, thereby generating ultrasonic
waves.
Receive Channel
The Receive Channel serves the function of an Analog Digital Conversion, which enables
Beamforming by amplifying the Echo propagated through, and reflected from, the media of
human body.
It consists of a Limiter, a Pre-Amp, a TGC-Amp, a Low-Pass Filter, and an A/D Converter.
1) Limiter
It removes unnecessary signals from the Echo signals returned through High Voltage
Switch of PSA(Probe Select Assembly. Tx Pulse up to 180 Vpp and echo signals of a few
mV are mixed together, but since the RX data actually needed are echo signals of
extremely small magnitude in mV range, the Tx Pulse must be eliminated before they are
sent to the Pre-Amp. The Limiter removes signal over approximately 0.6V before sending
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