FM1246/HM/I PHILIPS [NXP Semiconductors], FM1246/HM/I Datasheet - Page 2

• Manufacturer Part Number: FM1246/HM/I
• Description: Desktop video & FM radio module system CCIR I
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Components
FEATURES
DESCRIPTION
The FM1246 front-end is designed to receive both TV and
FM stereo signals in the PC Multimedia environment. The
units are available with separate 75
FM broadcast reception. The input connectors available
are either standard phono or IEC type (female for TV, male
for FM radio). The tuning, bandswitching and antenna
selection are made through the I
The front-end covers the TV bands from 45.75 MHz to
855.25 MHz. The FM band covers the standard
87.50 MHz to 108.00 MHz. An RDS decoder can be
connected to the AF-MPX output. The FM1246 meets the
input immunity and radiation requirements of CENELEC.
The FM1246 consists of a TV tuner, an FM radio tuner and
an IF section, all on a single PCB. The front-end is
assembled in a metal housing made of a rectangular
tin-plated steel frame, with front and rear covers, which
have soldered contacts to the frame. The two phono or
IEC antenna connectors (female for TV, male for FM
radio) are mounted on one side of the frame for the TV/FM
signal inputs. All other connections are made via pins at
the bottom.
The TV IF section uses an intercarrier SAW filter, followed
by a true-synchronous vision IF demodulator (PLL) IC. The
analog AFC voltage is fed to the 5-level A/D converter in
the PLL tuning IC, so that the AFC status can be read via
the I
1997 May 14
System I and FM radio broadcast
True 5 V device (low power dissipation)
Full TV frequency range from channel A (45.75 MHz) to
channel 69 (855.25 MHz)
FM radio band coverage from 87.50 to 108.00 MHz
PLL controlled tuning
Programmable PLL step size (31.25, 50 or 62.5 kHz)
True-synchronous vision IF demodulator (PLL)
Ultra-linear FM PLL demodulator for FM radio broadcast
Demodulated video output, AF sound output, second
sound IF output
I
information
Complies with European regulations on radiation, signal
handling and immunity “CENELEC 55020, 55013’’
Small horizontally mounted metal housing.
Desktop video & FM radio module
system CCIR I
2
C-bus control of tuning, address selection, AFC status
2
C-bus.
2
C-bus.
inputs for TV and
2
In the FM radio mode, the level detector and AFT functions
are provide for the auto-search routines. The level detector
and AFT status can be read from the A/D bits in the
status-byte. The mute function is also provided to
suppress the audio output signal, if required.
The tuner AGC for both TV and FM radio operation, is
generated with a novel AGC detector which measures the
IF signal level directly at the tuner IF output pins. As
opposed to the conventional AGC detector, this new circuit
allows a higher take-over level and offers superior
immunity against tuner overload.
The demodulation of the TV sound and FM radio IF
(10.70 MHz) is done with a PLL demodulation circuit
contained in the IF IC. In the FM radio mode, the
multiplexed AF signal is then channelled to a stereo
decoder IC which extracts the left/right analog signals.
The multiplexed audio signal is also available at pin 25 to
support RDS implementations. The 2
is provided to connect external (analog 2 carrier or digital)
stereo processing.
ORDERING INFORMATION
MARKING
The following items of information are printed on a sticker
that is on the top cover of the tuner:
FM1246/HM/PH
FM1246/HM/I
Type number
Code number
Origin letter of factory
Change code
Year and week code.
TYPE
standard phono
IEC connector
DESCRIPTION
Preliminary specification
nd
IF TV sound output
3139 147 13901
3139 147 13911
CATALOGUE
NUMBERS
FM1246