DIN
LIN
INPUT
SELECT
LOOPEN
EQEN
INPUT
SAMPLER
FRAME
DEMUX
D-FIELD
DECODER
D0..D19
FLAG
FDIS
PHASE /
FREQ
DETECT
INTERNAL
CLOCKS
DAV*
C-FIELD
DECODER
CAV*
FF
ERROR
CLOCK
GENERATOR
FILTER
LINKRDY
STATE
MACHINE
VCO
CLOCK
SELECT
STAT1
STAT0
PH1
CAP0
0.1 µF
CAP1
FLAGSEL
TCLK
SMRTST1*
SMRTST0*
TCLKSEL
M20SEL
Figure 5. HDMP-1024 Receiver Block Diagram.
HDMP-1024 Rx Block
Diagram
The HDMP-1024 receiver was
designed to convert a serial data
signal sent from the HDMP-1022
into either 16,17, 20, or 21 bit
wide parallel data. In doing this, it
performs the functions of
• Clock Recovery
• Data Recovery
• Demultiplexing
• Frame Decoding
• Frame Synchronization
• Frame Error Detection
• Link State Control
Input Select
The input select block determines
which input line is used. In
normal operation (LOOPEN=0),
DIN is accepted as the input
signal. For improved distance and
BER using coax cable, an input
equalizer may be used by
asserting EQEN. By setting
622
LOOPEN high, the receiver
accepts LIN as the input signal.
This feature allows for loop back
testing exclusive of the
transmission medium.
Phase/Freq Detect
This block compares either the
phase or the frequency of the
incoming signal to the internal
serial clock, generated from the
Clock Select block. The frequency
detect disable pin (FDIS) is set
high to disable the frequency
detector and enable the phase
detector. See
HDMP-1024 (Rx)
Phase Locked Loop
for more
details. The output of this block,
PH1, is used by the filter to
determine the control signal for
the VCO.
Filter
This is a loop filter that accepts
the PH1 output from the Phase/
Freq Detector and converts it into
a control signal for the VCO. This
control signal tells the VCO
whether to increase or decrease
its frequency. The Filter uses the
PH1 input to determine a propor-
tional signal and an integral
signal. The proportional signal
determines whether the VCO
should increase or decrease its
frequency. The integral signal
filters out the high frequency PH1
signal and stores a historical PH1
output level. The two signals
combined determine the magni-
tude of frequency change of the
VCO.
VCO
This is the Voltage Controlled
Oscillator that is controlled by the
output of the Filter. It outputs a
high speed digital signal to the
Clock Select.
ACTIVE
DIV1
DIV0
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