MSP 3400C
PRELIMINARY DATA SHEET
4. Architecture of the MSP 3400C
Some combinations of SAW filters and sound IF mixer
ICs, however, show large picture components on their
outputs. In this case, filtering is recommended. It was
found that the high pass filters formed by the coupling
capacitors at pins ANA_IN1+ and ANA_IN2+ as shown
in the application diagram are sufficient in most cases.
Fig. 4–1 shows a simplified block diagram of the IC. Its
architecture is split into three functional blocks:
1. demodulator section
2. digital signal processing (DSP) section performing
audio baseband processing
4.1.2. Quadrature Mixers
3. analog section containing two A/D-converters,
6 D/A-converters, and SCART switching facilities
The digital input coming from the integrated A/D conver-
ter may contain audio information at a frequency range
of theoretically 0 to 9 MHz corresponding to the selected
standards. By means of two programmable quadrature
mixers two different audio sources, for example FM1
and FM2, may be shifted into baseband position. In the
following, the two main channels are provided to pro-
cess either:
4.1. Demodulator Block
4.1.1. Analog Sound IF – Input Section
The input pins ANA_IN1+, ANA_IN2+, and ANA_IN–
offer the possibility to connect two different sound IF
sources to the MSP 3400C. By means of bit [8] of
AD_CV (see Table 6–3), either terrestrial or satellite
sound IF signals can be selected. The analog-to-digital
conversion of the preselected sound IF signal is done by
a flash-converter, whose output can be used to control
anautomaticgaincircuit(AGC), providingoptimumlevel
for a wide range of input levels. It is possible to switch
between automatic gain control and a fixed (setable) in-
put gain. In the optimum case, the input range of the A/D
converter is completely covered by the sound IF source.
– FM mono (channel 2) or
– FM2 (channel 1) and FM1 (channel 2).
Two independent digital oscillators are provided to gen-
erate two pairs of sin/cos-functions. Two programmable
increments, tobedividedupintoLow-andHighPart, de-
termine frequency of the oscillator, which corresponds
to the frequency of the desired audio carrier. In section
6.1., format and values of the increments are listed.
S_CL / ADR_CL
S_DA_IN / ADR_DA
I2S_DA_OUT
I2S_CL
AUD_CL_OUT XTAL_OUT
XTAL_IN
I2S_WS
I2S_DA_IN_1/2
S_ID / ADR_WS
2
SBUS/ADR Interface
Demodulator
I S Interface
Audio PLL
S1..4
I2S1/2L/R I2SL/R
Sound IF
DACM_L
LOUD-
SPEAKER L
D/A
FM1 / AM
FM2
ANA_IN1+
ANA_IN2+
Loudspeaker
LOUD-
SPEAKER R
DACM_R
D/A
DFP
IDENT
Mono
D/A
D/A
DACA_L
MONO_IN
HEADPHONE L
HEADPHONE R
Headphone
DACA_R
SC1_IN_L
SCART1
SCART_L
SCART_R
SC1_IN_R
A/D
A/D
SC2_IN_L
D/A
D/A
SCART_L
SCART_R
SC1_OUT_L
SCART2
SCART 1
SC1_OUT_R
SC2_IN_R
SC2_OUT_L
SC3_IN_L
SCART 2
SC2_OUT_R
SCART3
SCART Switching Facilities
SC3_IN_R
Fig. 4–1: Architecture of the MSP 3400C
MICRONAS INTERMETALL
9
MICRONAS [ MICRONAS ]
