HMP8170 Datasheet, PDF (13/33 Pages) Intersil Corporation – NTSC/PAL Video Encoder

HMP8170, HMP8171, HMP8172, HMP8173
Macrovision
The HMP8171 and HMP8173 provide the copy protection
system specified by the Macrovision Antitaping Process for
Digital Platforms document, revision 7.01, September 6, 1996.
The devices are protected by U.S. patent numbers
4,631,603, 4,577,216, and 4,819,098 and other intellectual
property rights. The use of Macrovision’s copy protection
technology in the device must be authorized by Macrovision
and is intended for home and other limited pay-per-view
uses only, unless otherwise authorized in writing by
Macrovision. Reverse engineering or disassembly is
prohibited.
Additional information about Macrovision in the HMP8171
and HMP8173 is available to Macrovision Authorized Buyers
only. Tech Brief 359, HMP8171/HMP8173 Macrovision
Registers provides the details required.
Analog Outputs
The HMP817x converts the video data into analog signals
using four 10-bit DACs running at the CLK2 rate. The DACs
output a current proportional to the digital data. The full scale
output current is determined by the reference voltage VREF
and an external resistor RSET. The full scale output current
is given by:
I_FULLSCALE (mA) = 3.9 * VREF (V)/RSET (kΩ)
(EQ 1.)
VREF must be chosen such that it is within the part’s
operating range; RSET must be chosen such that the
maximum output current is not exceeded.
If the VREF pin is not connected, the HMP817x uses the
internal reference voltage. Otherwise, the applied voltage
overdrives the internal reference. If an external reference is
used, it must decoupled from any power supply noise. An
example external reference circuit is shown in the
Applications section.
The HMP817x generates 1V_P-P nominal video signals
across 37.5Ω loads, corresponding to doubly terminated
75Ω lines. The encoder may also drive larger loads. The full
scale output current and load must be chosen such that the
maximum output voltage is not exceeded.
Output DAC Filtering
Since the DACs run at 2x the pixel sample rate, the sin(x)/x
rolloff of the outputs is greatly reduced, and there are fewer
high frequency artifacts in the output spectrum. This allows
using simple analog output filters. The analog output filter
should be flat to F_s/4 and have good rejection at 3F_s/4.
Example filters are shown in the Applications section.
Composite + Y/C Output Mode
The HMP817x provides composite with S-video output
mode. When S-video outputs are selected, the encoder
outputs the luminance, modulated chrominance, and two
copies of the composite video signals. All four outputs are
time aligned. The output pin assignments are summarized in
Table 12.
Composite + RGB Output Mode
The HMP8172/HMP8173 also provide composite with
component RGB output mode. When analog RGB video is
selected, the HMP817x transforms the filtered 8:8:8 YCbCr
data into 8:8:8 RGB data. The transform matrix uses
different coefficients to generate NTSC or PAL video levels.
The analog RGB outputs have a range of 0.3-1.0V with an
optional blanking pedestal. Composite sync information
(0.0-0.3V) may be optionally added to the green output. VBI
data is not included on the RGB outputs. The HMP817x also
generates composite video when in RGB output mode. All
four outputs are time aligned.
The HMP817x provides selectable pin outs for the RGB
outputs. When the SCART compatibility bit is cleared, the
analog composite video is output onto the NTSC/PAL 1 pin.
Red information is output onto the NTSC/PAL 2 pin, blue
information is output onto the C pin, and green information is
output onto the Y pin.
When the bit is set, the analog composite video is output
onto the Y pin. Red information is output onto the C pin, blue
video is output on the NTSC/PAL 2 pin, and the green signal
is output on the NTSC/PAL 1 pin. The output pin
assignments are summarized in Table 12.
PIN NAME
Y
C
NTSC/PAL 1
NTSC/PAL 2
PIN #
3
7
11
15
TABLE 12. OUTPUT PIN ASSIGNMENTS
OUTPUT MODE (SCART SELECT BIT)
COMP. WITH Y/C
(X)
COMP. W/ RGB
(0)
COMP. W/ RGB
(1)
Luma
Green
Composite
Chroma
Blue
Red
Composite
Composite
Green
Composite
Red
Blue
COMP. W/ YUV
(X)
Composite
V
Y
U
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