u2514b ETC-unknow, u2514b Datasheet - Page 5

• Manufacturer Part Number: u2514b
• Description: Am/fm Receiver Digital Tuning With Fm-stereo Decoder
• Manufacturer: ETC-unknow

TELEFUNKEN Semiconductors
Rev. A2, 04-Nov-96
AMIFIN
The input impedance of the AM IF amplifier is 3.3 k
according to the required impedance of most ceramic
filters. The input refers to VREF (Pin 14).
FMIFIN
The input impedance of the FM IF amplifier is 330
according to the required impedance of most FM ceramic
filters. The input referes to GND (Pin 16).
AMIFIN
FMIFIN
12423
12
40
13
m
3.3 k
A
Figure 10.
Figure 11.
GND
Preliminary Information
VREF
12421
W
W
FMDET
The discriminator allows the connection of a ceramic
resonator or LC tank. A minimization of THD and
adjustment of center frequency versus temperature can
only be achieved by using a LC tank. This performs a
temperature independent stop signal.
AFSM
A capacitor is connected between AFSM (Pin 11) and
GND for smoothing of the FM-AF. This is necessary to
generate a modulation independent stop signal. (Because
the deviation of the FM signal (75 kHz) can be greater
than the stop signal window (25 kHz)). In the
AM-search-mode, the external capacitor smoothes the
demodulated AM-IF-signal.
150
m
25
A
MPXOUT
VREF
Figure 12.
Figure 13.
100 k
11
U2514B
FMDET
AFSM
15
12422
12424
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