PROJECT: HF-17132
DESCRIPTION: Tuner ECO5 AM/FM receiver on TEA5757H
STATUS: n
LOCALISATION: PG
DOCUMENTATION: PCB: TPD57132
DIMENSIONS: 117 x 82 mm
VERSION: 0.00
Project Info
AM/FM tuner board with TEA5757, no tested yet but it seems OK. I found and repaired some cold solder joints only.
FUNCTIONAL DESCRIPTION
The TEA5757; TEA5759 is an integrated AM/FM stereo
radio circuit including digital tuning and control functions.
The radio
The AM circuit incorporates a double balanced mixer,
a one-pin low-voltage oscillator (up to 30 MHz) and is
designed for distributed selectivity.
The AM input is designed to be connected to the top of
a tuned circuit. AGC controls the IF amplification and for
large signals it lowers the input impedance of the
AM front-end.
The first AM selectivity can be an IF-Tank (IFT) as well as
an IFT combined with a ceramic filter; the second one is
an IFT.
The FM circuit incorporates a tuned RF stage, a double
balanced mixer, a one-pin oscillator and is designed for
distributed IF ceramic filters. The FM quadrature detector
uses a ceramic resonator (or LC).
The PLL stereo decoder incorporates a signal dependent
stereo-blend circuit and a soft-mute circuit.
Tuning
The tuning concept of the Self Tuned Radio (STR) is
based on FUZZY LOGIC: it mimics hand tuning (hand
tuning is a combination of coarse and fine tuning to the
qualitatively best frequency position). As a consequence
the tuning system is very fast.
The tuning algorithm, which is controlled by the sequential
circuit (see Fig.1), is completely integrated; so there are
only a few external components needed.
The bus and the microcontroller can be kept very simple.
The bus only consists of three wires (BUS-CLOCK, DATA
and WRITE-ENABLE). The microcontroller must basically
give two instructions:
Preset operation
Search operation
Band range of the synthesizer AM mode: 0.144 - 30 MHz
FM mode: 50 - 150 MHz
Thus I'm not expecting high parameters from this circuit... but self tuning can be used for signals detection, so some experiments can be made.
Simple driver can be quickly written on HAVR for HF-6030.