TDA9550 PHILIPS [NXP Semiconductors], TDA9550 Datasheet - Page 103

• Manufacturer Part Number: TDA9550
• Description: TV signal processor-Teletext decoder with embedded m-Controller
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
49. Conditions: frequency is 50 Hz; normal mode; VS = 1F.
50. The output range percentages mentioned for E-W control parameters are based on the assumption that 400 A
51. The ICs have a zoom adjustment possibility for the horizontal and vertical deflection. For this reason an extra DAC
52. At a chrominance input voltage of 660 mV (p-p) (colour bar with 75% saturation i.e. burst signal amplitude
53. The ACL function can be activated by via the ACL bit in the subaddress 20H. The ACL circuit reduces the gain of the
54. This parameter indicates the bandwidth of the complete chrominance circuit including the chrominance bandpass
55. The subcarrier output is combined with a 3-level switch output which can be used to switch external circuits like
56. Because of the 2-point black current stabilization circuit both the black level and the amplitude of the RGB output
2000 Jun 22
TV signal processor-Teletext decoder with
embedded -Controller
b) Standard mode ‘narrow window’.
c) Standard TV-norm (divider ratio 525 (60 Hz) or 625 (50 Hz).
The vertical divider needs some waiting time during channel-switching of the tuner. When a fast reaction of the
divider is required during channel-switching the system can be forced to the search window by means of the NCIN bit
in subaddress 25H.
When RGB signals are inserted the maximum vertical frequency is increased to 72 Hz. This has the consequence
that the circuit can also be synchronised by signals with a higher vertical frequency like VGA.
variation in E-W output current is equivalent to 20% variation in picture width.
has been added in the vertical amplitude control which controls the vertical scan amplitude between 0.75 and 1.38
of the nominal scan. At an amplitude of 1.06 of the nominal scan the output current is limited and the blanking of the
RGB outputs is activated. This is illustrated in Fig. 43.
When the vertical amplitude is compressed (zoom factor <1) it is still possible to display the black-current measuring
lines in the vertical overscan. The feature is activated by means of the OSVE-bit in sub-address 26H. Because the
vertical deflection output stage needs some time for the excursion from the top of the picture to the required position
on the screen the vertical blanking is increased when the OSVE-bit is activated. The shape of the vertical deflection
current for a zoom factor of 0.75 with OSVE activated is given in Fig. 44. The exact timing of the measuring pulses
and vertical blanking for the various conditions is given in Fig. 46.
a) The nominal scan height must be adjusted at a position of 19 HEX of the vertical ‘zoom’ DAC.
300 mV (p-p)) the dynamic range of the ACC is +6 and 20 dB.
chroma amplifier for input signals with a chroma-to-burst ratio which exceeds a value of 3.0.
filter. The bandwidth of the low-pass filter of the demodulator is approximately 1 MHz.
sound traps etc. This output is controlled by the CMB1 and CMB0 bits in control byte 22H. The subcarrier signal is
available when CMB1/0 are set to 0/1. During the demodulation of SECAM signals the subcarrier signal is only
available during the vertical retrace period. The frequency is 4.43 MHz in this condition. When CMB1/0 are set to 00
in versions for 90 picture tubes (no EW output) the output is high ohmic.
signals depend on the drive characteristic of the picture tube. The system checks whether the returning measuring
currents meet the requirement and adapts the output level and gain of the circuit when necessary. Therefore the
typical value of the black level and amplitude at the output are just given as an indication for the design of the RGB
output stage.
This mode is switched on when more than 15 succeeding vertical sync pulses are detected in the narrow window.
When the circuit is in the standard mode and a vertical sync pulse is missing the retrace of the vertical ramp
generator is started at the end of the window. Consequently, the disturbance of the picture is very small. The
circuit will switch back to the search window when, for 6 successive vertical periods, no sync pulses are found
within the window.
When the system is switched to the narrow window it is checked whether the incoming vertical sync pulses are
in accordance with the TV-norm. When 15 standard TV-norm pulses are counted the divider system is switched
to the standard divider ratio mode. In this mode the divider is always reset at the standard value even if the vertical
sync pulse is missing.
When 3 vertical sync pulses are missed the system switches back to the narrow window and when also in this
window no sync pulses are found (condition 3 missing pulses) the system switches over to the search window.
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TDA955X/6X/8X PS/N1 series
Tentative Device Specification