TEA6100 Philips Semiconductors (Acquired by NXP), TEA6100 Datasheet - Page 5

• Manufacturer Part Number: TEA6100
• Description: TEA6100; Fm/if System And Microcomputer-based Tuning Interface
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
PINNING
FUNCTIONAL DESCRIPTION (see Figs 1 and 16)
The IF amplifier consists of four balanced limiting amplifier stages, two separate inputs (AM and FM) and one output.
Software programming (see Table 2; Figs 4 and 5) allows the input signals (AM/FM) to be inserted on either input (pin
18 or 19). The output drives the frequency counter and via the mute stage, drives the quadrature detector. The output of
the quadrature detector is applied to an audio stage (which has a single-ended output). The AM/FM level amplifier, which
is driven by 5 IF level detectors, generates a signal dependent d.c. voltage. The level output voltage is used internally to
control the mute stage and, if required, the signal can be used externally to control the stereo channel separation and
frequency response of a stereo decoder. The signal is also feed to the analogue-to-digital converter (ADC). Due to the
front-end spread in the amplification, the level voltage is made adjustable (LADJ, pin 14). The level voltage amplifier
controls the mute stage and this insures the 3 dB limiting point remains constant, independent of the front-end spread.
AM and FM mode have different front-end circuitry, therefore LADJ must be adjustable for both inputs.
The output voltage of the level amplifier is dependent upon the field strength of the input signal. The multi-path of the FM
signal exists in the AM modulation of the input signal. The following method is used to determine the level information
and the amount of multi-path (as a DC voltage):
In the FM mode, the DC information concerning the multi-path is available at pin 5 and the level information is available
at pin 3.
August 1987
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
the IF level detector detects the multi-path and feds the signal, via the level amplifiers, to the external bandpass filter
(pin 3) and ADC1
the signal is then fed to an internal rectifier
the rectified signal is then fed to an amplifier, so at pin 5 the DC level information is externally available and internally
used by ADC2
FM/IF system and microcomputer-based
tuning interface
V
MUTE IN
LA OUT
RT/A IN
RT/A OUT
F
DGND
V
SCL
SDA
LF OUT
Q-DET
Q-DET
LADJ
V
FB DEC
FB DEC
INPUT 1
INPUT 2
AGND
ref
P1
P2
ref
analogue supply voltage
mute input
level amplifier output
rectifier/amplifier input
rectifier/amplifier output
reference frequency input
digital ground
digital supply voltage
serial clock line; I
serial data line; I
audio output signal
phase shift for quadrature
detector
phase shift for quadrature
detector
level amplifier adjustment
reference voltage
decoupled feedback
decoupled feedback
FM/AM IF input
AM/FM IF input
analogue ground
2
2
C bus
C bus
5
Fig.2 Pinning diagram.
Product specification
TEA6100