TDA9875A Philips Semiconductors, TDA9875A Datasheet - Page 28

• Manufacturer Part Number: TDA9875A
• Description: Digital TV Sound Processor DTVSP
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Notes
1. Definitions of levels and level setting:
2. All analog and digital supply ground pins are connected internally.
3. Set demodulator to AM mode. Apply an AM carrier (with 1 kHz and 100%) to one channel. Check AGC step. Switch
4. NICAM in accordance with “EBU specification” . Audio performance is limited by the dynamic range of the NICAM728
5. FM source; in dual mode only A (respectively B) signal modulated; measured at B (respectively A) channel output;
6. FM source; in stereo mode only L (respectively R) signal modulated; measured at R (respectively L) channel output;
7. If the supply voltage for the TDA9875A is switched off, because of the ESD protection circuitry, all audio input pins
8. The SCART specification allows a signal level of up to 2 V (RMS). Because of signal handling limitations due to the
9. ADC level adjust is 6 dB, all other level adjusts are 0 dB. If an external 3 dB divider is used set output buffer gain
1999 Dec 20
X
X
X
J
D
A
Digital TV Sound Processor (DTVSP)
SYMBOL
a) The full-scale level for analog audio signals is 1.4 V (RMS).
b) The nominal level at the digital crossbar switch is defined at 15 dB (full-scale).
c) Nominal audio input levels for external and mono: 500 mV (RMS) at 9 dB (full-scale).
d) See also Tables 7 and 8.
AGC off and set AGC to the gain step found. Measure the 1 kHz signal level of this channel and take it as a reference.
Switch to the other SIF input to which no signal is connected and which is terminated with 50 . Now measure the
1 kHz crosstalk signal level. The SIF source resistance should be low (50 ).
system. Due to compansion, the quantization noise is never lower than 62 dB (unweighted RMS) with respect to
the input level.
V
V
the transmitter.
are short-circuited. To avoid a short-circuit at the SCART inputs a 15 k resistor ( 3 dB divider) has to be used.
5 V supply voltage for the TDA9875A, there is a need for fixed 3 dB attenuators at the SCART inputs. To achieve
SCART-to-SCART copies with 0 dB gain, there are 3 dB/0 dB amplifiers at the outputs of SCART 1 and SCART 2
and at the line output. The attenuator is realized by an internal resistor that works together with an external series
resistor as a voltage divider. With this voltage divider the maximum SCART input signal level of 2 V (RMS) is scaled
down to 1.4 V (RMS) at the input pin. To avoid clipping, the 3 dB gain must not be used if the SCART input signal is
larger than 1.4 V (RMS).
to 3 dB, tone control to 0 dB, AVL off and volume control to 0 dB.
o
o
= 1 V (RMS) of modulated channel.
= 1 V (RMS) of modulated channel. The stereo channel separation may be limited by adjustment tolerances of
adjustment tolerance
drift
ageing
PARAMETER
across temperature range
CONDITIONS
28
MIN.
TYP.
Product specification
TDA9875A
30
30
5
MAX.
10
10
10
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year
UNIT
–
6
6
6