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4.4
Steerable CW Doppler Unit EZU-ST5
4.4.1
General and board description
Composition
PCBs.
Outline of PCB : This is for steerable CW Doppler by sector probe. CW PCB carry out
4.4.2
CW circuit description
CW PCB is divided into the following 11 blocks.
1.
TRANSMITTING BUFFER (Transmitting buffer part)
A buffer to drive transmit Amp of AWP P.C.B., to the transmit signal sent from
DBF P.C.B.
2.
MIXER (Demodulation circuit part)
Detects the element of Doppler shift by mixing with the reference wave.
3.
HIGH PASS FILTER (High frequency pass filter part)
Removes the unnecessary low frequency element contained in doppler signal by
body movement, to receive signal of each channnel.
4.
ADD (Adding part)
Adds the received signals.
5.
HIGH PASS FILTER (High frequency pass filter part)
Removes the unnecessary low frequency element contained in doppler signal by
body movement, for added receive signal.
6.
GAIN (Gain process part)
Amplifies or attenuates Doppler signal.
7.
ANALOG WALL FILTER (High area pass filter part)
Deletes unnecessary low frequency element which is mixed into Doppler signal by
body movement.
8.
ANTI ALIASING FILTER (Anti aliasing filter part)
Deletes unnecessary high frequency element to prevent aliasing by A/D converter
described later.
9.
AD CONVERTER (AD convert part)
Converts the added receive signal to digital signal and sends to EPI P.C.B.
10. CW CONTROL (CW control part)
Controls the frequency setting for reference wave, the gain setting and other
settings.
11. LO GENERATOR (Mixing clock generate part)
Generates the clock of Mixer.
: EZU-ST5 is an option of EUB-5500 and consists of the following
1.
CW PCB
phase arrangement, addition, demodulation and filter process.
4 – 24
L1E-EA0229
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