TDA935x Philips, TDA935x Datasheet - Page 96

• Manufacturer Part Number: TDA935x
• Description: TV Signal Processor-Teletext Decoder with Embedded u-Controller
• Manufacturer: Philips

Philips Semiconductors
22. The deemphasis pin can also be used as additional audio input. In that case the internal (demodulated FM signal)
23. The signal-to-noise ratio is measured under the following conditions:
24. Audio input signal 200 mV
25. Audio input signal 1 V
26. Unweighted RMS value, audio input signal 500 mV
27. Audio attenuator at 20 dB; temperature range 10 to 50 C.
28. In various versions the Automatic Volume Levelling (AVL) function can be activated. The pin to which the external
29. Signal with negative-going sync. Amplitude includes sync pulse amplitude.
30. This parameter is measured at nominal settings of the various controls.
31. Indicated is a signal for a colour bar with 75% saturation (chroma : burst ratio = 2.2 : 1).
32. The contrast and saturation control is active on the internal signal (YUV) and on the external RGB/YUV input. The
33. The YUV input signal amplitudes are based on a colour bar signal with 75/100% saturation.
34. When the decoder is forced to a fixed subcarrier frequency (via the CM-bits) the chroma trap is always switched-on,
35. Valid for a signal amplitude on the Y-input of 0.7 V black-to-white (100 IRE) with a rise time (10% to 90%) of 70 ns
36. The ratio between the positive and negative peaks can be varied by means of the bits RPO1 and RPO0 in
37. For video signals with a black level which deviates from the back-porch blanking level the signal is “stretched” to the
2001 Jan 18
TV signal processor-Teletext decoder with
embedded -Controller
must be switched off. This can be realised by means of the SM (sound mute) bit. When the vision IF amplifier is
switched to positive modulation the signal from the FM demodulator is automatically switched off. The external signal
must be switched off when the internal signal is selected.
a) Input signal to the SNDIF pin (activated via SIF bit) with an amplitude of 100mV
b) Output signal measured at the AUDEEM pin. The noise (RMS value) is measured according to the CCIR 468
capacitor has to be connected depends on the IC version. For the 90 types the capacitor is connected to the EW
output pin. For the 110 types a choice can be made between the AVL function and a sub-carrier output / general
purpose switch output. The selection must be made by means of the CMB0 and CMB1 bit in subaddress 22H. More
details about the sub-carrier output are given in the parameters D.10.
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 AVL bit in subaddress 29H.
The AVL is active over an input voltage range (measured at the deemphasis output) of 150 to 1500 mV
control curve is given in Fig.39. The control range of +6 dB to 14 dB is valid for input signals with 50% of the
maximum frequency deviation.
Text/OSD input can be controlled on brightness only. Nominal contrast is specified with the DAC in position 20 HEX.
Nominal saturation as maximum 10 dB.
also when no colour signal is identified. In the automatic mode the chroma trap is switched-off when no colour signal
is identified.
and the video switch in the Y/C mode. During production the peaking function is not tested by measuring the
overshoots but by measuring the frequency response of the Y output.
subaddress 2EH. For ratios which are smaller than 1.8 the positive peak is not affected and the negative peak is
reduced.
blanking level. The amount of correction depends on the IRE value of the signal (see Fig.40). The black level is
detected by means of an internal capacitor. The black level stretcher can be switched on and off via the BKS bit in
subaddress 2DH. The values given in the specification are valid only when the luminance input signal has an
amplitude of 1 V
definition.
p-p
.
RMS
RMS
and the volume control setting such that no clipping occurs in the audio output.
. Measured with a bandwidth of 15 kHz and the audio attenuator at 6 dB.
RMS
96
, audio attenuator at 6 dB.
TDA935X/6X/8X PS/N2 series
RMS
Tentative Device Specification
, f
MOD
= 1 kHz and f = 27 kHz
RMS
. The AVL