ISL59960 Datasheet, PDF (11/17 Pages) Intersil Corporation – 960MegaQ™: An Automatic 960H and Composite Video Equalizer, Fully-Adaptive to 4000 Feet

ISL59960
go low until/unless the device is reset by toggling the INVERT pin.
A reset should only be necessary if the length or type of cable
was changed without cycling power.
To enable the Lock Until Reset mode, tie the LOCKED output pin
to the FREEZE input pin as shown in Figure 9 on page 9.
To generate a reset (and trigger a re-equalization), toggle the
external INVERT pin. Depending on the initial state of INVERT,
this would be a high-low-high or low-high-low sequence.
CONTINUOUS UPDATE
In the Continuous Update mode, 960MegaQ™ will continuously
try to find the optimum equalization solution. When the
equalization has settled for 100 sequential video lines with no
changes, the LOCKED pin will go high. However, once lock is
achieved, noise and average-picture-level changes may cause the
device to unlock, causing some image perturbation while
960MegaQ™ re-equalizes.
The Continuous Update mode is enabled whenever the FREEZE
pin is set to a logic low (grounded).
Polarity Detection and Correction
960MegaQ™ features polarity detection and correction,
automatically detecting incorrectly-wired input signals and
inverting the signal inside the IC as necessary. The detected
polarity is indicated by the state of the INVERT pin.
The INVERT pin has 2 modes of operation. It is typically used to
indicate whether or not the incoming signal is inverted (the “+”
signal on the “-” input and vice-versa). The state of the invert
signal is then used to tell the signal processing logic whether or
not to invert the signal in the signal path.
A logic high on INVERT indicates that the positive differential
input signal is on IN- (pin 5) and the negative differential input
signal is on IN+ (pin 3). A logic low indicates nominal polarity.
However, the unique design of the INVERT I/O pin (Figure 12)
also allows 960MegaQ™’s internal inversion detector to be
overdriven externally, forcing 960MegaQ™ to invert or not invert
the signal regardless of the state of the inversion detection
function. This is not necessary in normal operation, but it may
improve performance in particularly noisy environments when
the polarity of the signal is guaranteed to be correct.
INVERT
PIN
INVERSION
DETECTION
LOGIC
13kΩ
ISL59960
SIGNAL
PROCESSING
FIGURE 12. INVERT PIN STRUCTURE
The COLOR Pin
The color pin has 2 modes of operation. It is typically used to
indicate whether or not the incoming signal has a colorburst or
not. The state of the color signal is then used to tell the signal
processing logic whether or not it can rely on the presence of a
colorburst signal. A logic high indicates a color signal; a logic low
indicates monochrome.
COLOR
PIN
COLOR
DETECTION
LOGIC
13kΩ
ISL59960
SIGNAL
PROCESSING
FIGURE 13. COLOR PIN STRUCTURE
However, the unique design of the COLOR I/O pin (Figure 13) also
allows 960MegaQ™’s internal color detector to be overdriven
externally. This is not necessary in normal operation, but it may
improve performance in particularly noisy environments when
the signal type is predetermined.
Monochrome Video Signals
960MegaQ™ will equalize monochrome signals to the same
distance as color signals. However, due to the high level of noise
past ~3500 feet, the COLOR and LOCKED indicators may
become invalid for monochrome signals. The device will still
equalize properly if this occurs.
Security Cameras
960MegaQ™ is ideal for security camera installations.
The automatic adaptive equalizer doesn't need any active silicon
on the transmit side of the cable, enabling upgrading of older
installations without having to touch the installed camera base,
including older monochrome cameras.
960MegaQ™ automatically adjusts for wiring polarity errors as
well as for optimum image quality. These features eliminate the
need for the installer to make any adjustments.
With an extended equalization range of 4000ft, the ISL59960
enables cameras to be placed in even more remote locations,
enabling coverage of up to three square miles from a single
monitoring station.
Additional Equalization Modes Available
With the Serial Interface
In addition to the Lock Until Reset and Continuous Update
modes, software control of 960MegaQ™ through the SPI
interface adds a Lock Until Signal Loss mode and a Manual
Equalization mode.
Note: When controlling 960MegaQ™ through the SPI interface,
the external FREEZE pin must be tied to ground (logic low).
Failure to keep FREEZE at a logic low will prevent the software
controls from working properly.
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FN8358.0
December 18, 2012