CYV270M0104EQ
Document Number: 001-12875 Rev. **
Page 4 of 9
Equalizer Operation
The CYV270M0104EQ is an adaptive video cable equalizer that
equalizes standard definition (SD) serial digital interface (SDI)
video data streams. The CYV270M0104EQ equalizer is
optimized to equalize up to 350m of Belden 1694A and Canare
L-5CFB cable at 270 Mbps. The device contains one power
supply and typically consumes 160 mW power at 3.3V. The
adaptive equalizer meets the SMPTE 259M and DVB-ASI video
standards. It meets all pathological requirements for SMPTE
259M as defined by RP178. The CYV270M0104EQ Video Cable
Equalizer is auto adaptive from 143 Mbps to 360 Mbps.
The CYV270M0104EQ equalizer has multiple variable gain
equalization stages that reverse the effects of the cable. This
equalization is achieved by separate regulation of the lower and
higher frequency components in the signal to give a clean output
eye diagram. The CYV270M0104EQ has DC restoration for
compensating the DC content of the SMPTE pathological
patterns.
SDI, SDI
CYV270M0104EQ accepts single-ended or differential serial
video data streams over 75
Ω coaxial cable. It is recommended
to AC couple the SDI and SDI inputs because they are internally
biased to 1.2V.
SDO, SDO
The CYV270M0104EQ has differential serial output interface
drivers that use Current Mode Logic (CML) drivers to provide
source matching for the transmission line. These outputs are
either AC coupled or DC coupled to HOTLink II receivers.
MCLADJ
Maximum Cable Length Adjust (MCLADJ) sets the approximate
maximum amount of cable to equalize. When the maximum
cable length set by MCLADJ is reached, the CD pin deasserts.
To enable automatic muting of the device when the signal is lost,
tie CD directly to MUTE.
The graph in Figure 2 on page 7 illustrates the voltage required
at MCLADJ input to equalize various Belden 1694A cables. The
same graph applies for Canare L-5CFB cables. If MCLADJ
functionality is not required, this pin should be left floating or tied
to ground to allow maximum equalized cable length.
MUTE
MUTE is an input pin that controls the muting of the equalizer’s
output.
If MUTE is set LOW, then the equalizer serial outputs are not
muted. If MUTE is set HIGH, then the equalizer serial outputs are
muted. When MUTE is active, the BYPASS setting is also
ignored.
Connecting CD to MUTE enables automatic muting of the
equalizer when the signal is lost.
Do not leave the MUTE pin floating. Always drive it to a known
state.
Carrier Detect (CD)
Carrier Detect is an active LOW output pin that indicates the
presence of a valid incoming data signal. When the incoming
data signal is present and maximum cable length does not
exceed the length that is set by MCLADJ, CD outputs a voltage
less than 0.8V.
When the incoming data stream is not present or maximum cable
length exceeds the length that is set by MCLADJ, CD outputs a
voltage greater than 2.8V.
Connecting CD to MUTE enables automatic muting of the
equalizer when the signal is lost.
BYPASS
The CYV270M0104EQ has a bypass mode that enables the user
to bypass the equalizer’s equalization and DC restoration
functions. When BYPASS is set HIGH, the signal presented at
the equalizer’s differential serial inputs (SDI, SDI) is routed to the
equalizer’s differential serial outputs (SDO, SDO) without equal-
izing.
When BYPASS is set LOW, the incoming video data stream is
equalized and presented at the equalizer‘s differential serial
outputs (SDO, SDO).
AGC
Place a 1
μF capacitor between the AGC and AGC pins of the
CYV270M0104EQ equalizer.
[+] Feedback
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
