Sony CCU-590 Maintenance Manual page 50

EN-156B Board
This board generates VBS, PIX, and WFM signals by the D-ENC from the Y, R-Y, and B-Y signals that
are A/D converted using the 27 MHz clock, and converts the signals to analog signals, and then outputs
them. This board also generates, D/A converts, and then outputs the R/G/B signals. The SDI signal is also
output through the half-band filter and format encoder.
VBS/WFM/PIX Signal Circuit
The 10 bit, 3.3 V p-p parallel T/R-Y/B-Y signals from the IV-57B board pass through the D-FF (IC102 to
IC105), and are then input into the CB generator IC106 where CB output and camera output are switched.
The CB output is switched in accordance with respective specifications such as 100 %, 75 %, SMPTE or
EIA. The IC106 output is then input into IC326 for digital encoding in which VBS, WFM, PIX, and other
signals are generated. The character signal and the SKIN GATE signal are also mixed at this time. The
generated signals are D/A converted, and are then output as analog signals.
Y/R-Y/B-Y, RGB Signal Circuit
The Y, R-Y, and B-Y signals input into IC106 are delayed in the built-in delay circuit to match the phase
with the VBS signal phase. The R/G/B signals are also generated by the built-in matrix circuit. IC106
selects which signals (Y/R-Y/B-Y or RGB) to output. The output signals of this IC are converted to
analog signals by IC107 to IC109, and are then output as Y or G signal, R-Y or R signal, and B-Y or B
signal.
Front Panel (RM-B750) Video Signal Processing Circuit
RGB signals must be supplied as signals for optional front panel. As described above, the IC output is
switched to either Y/R-Y/B-Y signals or RGB signals according to the setting of the CCU rear panel
output signal. When RGB is set, RGB signals are output as they are, but when Y/R-Y/B-Y is set, a circuit
to convert the IC output to RGB signals and output them is required. This is set by S1001.
IC101 and Q1001 to Q1006 are used as a Y/R-Y/B-Y to G signal converter circuit, and also as a G signal
output circuit when RGB is set. The signal output from the circuit is transferred to the character mixing
circuit, and is then output to the front panel. Such circuit is also provided for the R and B signals respec-
tively.
SDI Output
The Y, R-Y, and B-Y signals from IC106 are input into the half-band filter IC509 to be converted from
8:8:8 to 4:2:2 signals. Then the signals are input into IC502 where mixing of the character signals with
the SDI signal, mixing of the SKIN GATE signal are carried out. The signals are encoded to the SDI
signal format, and are then output. The signals are converted from parallel to serial signals by IC503 and
IC504, and are then output as SDI signals.
Subcarrier Genlock Circuit
IC326 perform subcarrier genlock synchronization. The SC digital data from IC326 is D/A converted by
IC301, and is then input into the phase comparator IC306. The subcarrier signal of the external sync
signal and the sync signal are also input into IC306 to compare their phases. The difference passes
through the burst gate, is A/D converted by IC311, and is then re-input into IC326 where subcarrier
genlock synchronization is carried out.
3-6
CCU-590/P/V1(E)