December 16, 1997
44
Philips Semiconductors
Tentative Device Specification
I
2
C-bus controlled PAL/NTSC/SECAM TV
processors
TDA884X/5X-N2 series
9.
10. The noise inverter is only active in the “strong signal mode” (no noise detected in the incoming signal)
11. The test set-up and input conditions are given in Fig.16. The figures are measured with an input signal of
10 mV RMS. The indicated parameter values are obtained when a capacitor with a value of 1 nF is connected in
parallel with the PLL loop filter on pin 5.
12. Measured at an input signal of 10 mV
RMS
. The S/N is the ratio of black-to-white amplitude to the black level noise
voltage (RMS value). B = 5 MHz. Weighted in accordance with CCIR 567.
13. The AGC response time is also dependent on the acquisition time of the PLL demodulator. The values given are valid
when the PLL is in lock.
14. The AFC control voltage is generated by the digital tuning system of the PLL demodulator. This system uses the X-tal
frequency of the colour decoder as a reference and is therefore very accurate. For this reason no maximum and
minimum values are given for the window sensitivity figures (parameters M.7.2 and M.7.3). The tuning information is
supplied to the tuning system via the I
2
C-bus. 2 bits are reserved for this function. The AFC value is valid only when
the SL-bit is 1.
15. The ratio of the output signal amplitudes of the deemphasis pin (pin 55) and the audio output (pin 15) is dependent
on the type and/or the frequency of the X-tals connected to the IC (indicated via the XA/XB bits). The indicated values
are valid for the PAL, PAL/NTSC and multi-standard versions when a 4.43 MHz X-tal is connected to pin 35 (pin 51
in the QFP-64 envelope). For the NTSC types and the other IC’s (when only 3.5 MHz X-tals are used) the gain
between the deemphasis output and the audio output is a factor 2 higher so that the audio output signal is not effected
by the lower frequency deviation of the M/N standard.
The test conditions are: Vi = 100 mV
RMS
, FM: 1 kHz,
f =
±
25/50 kHz.
16. Vi = 50 mV
RMS
, f = 4.5/5.5 MHz; FM: 70 Hz, +/- 50 kHz deviation; AM: 1.0 kHz, 30% modulation.
17. Vi = 100 mV
RMS
, f = 5.5 MHz; FM: 1 kHz, +/- 17.5 kHz deviation. Measured with a bandwidth of 15 kHz and the audio
attenuator at -6 dB.
18. Vi = 100 mV
RMS
, f = 4.5 MHz, FM: 1 kHz, +/- 100 kHz deviation.
19. Unweighted RMS value, Vi = 100 mV
RMS
, FM: 1 kHz, +/- 50 kHz deviation, audio attenuator at -6 dB.
20. Audio attenuator at -20 dB; temperature range 10 to 50
°
C.
21. The Automatic Volume Levelling (AVL) circuit stabilises automatically the audio output signal to a certain level which
can be set by means of the volume control. This AVL function prevents big audio output fluctuations due to variation
of the modulation depth of the transmitter. The AVL can be switched on and off via the I
2
C-bus.
For the TDA 8846/46A the AVL is active over an input voltage range (measured at the deemphasis output) between
75 and 750 mV
RMS
. For the TDA 8840/41/42 this input level is dependent on the X-tals which are connected to the
colour decoder. When only 3.5 MHz X-tals are connected (indicated via the XA/XB bits) the active input level is
identical to that of the TDA 8846/46A. When a 4.4 MHz X-tal is connected the input range is increased to 150 to 1500
mV
RMS
, this to cope with the larger FM swing of European transmitters.
The AVL control curve for the 2 standards is given in Fig.17 and Fig.18. The control range of +6 dB to
14 dB is valid
for input signals with 50% of the maximum frequency deviation.
22. Signal with negative-going sync. Amplitude includes sync pulse amplitude.
23. This parameter is measured at nominal settings of the various controls.
24. Indicated is a signal for a colour bar with 75% saturation (chroma : burst ratio = 2.2 : 1).
25. The saturation control is active on the internal signal (YUV) and on the second RGB input. The contrast control is
active on YUV and the 2 RGB inputs. Nominal contrast is specified with the DAC in position 20 HEX. Nominal
saturation as maximum -10 dB.
This figure is valid for the complete video signal amplitude (peak white-to-black), see Fig.15.