Philips Semiconductors
Objective specification
Integrated PAL and PAL/NTSC TV
processors
TDA8360; TDA8361; TDA8362
37. All frequency variations are referenced to 3.58/4.43 MHz carrier frequency.
All oscillator specifications are measured with the Philips crystal series 9922 520.
If the spurious response of the 4.43 MHz crystal is lower than −3 dB with respect to the fundamental frequency for a
damping resistance of 1 kΩ, oscillation at the fundamental frequency is guaranteed.
The spurious response of the 3.58 MHz crystal must be lower than −3 dB with respect to the fundamental frequency
for a damping resistance of 1.5 kΩ.
The catching and detuning range are measured for nominal crystal parameters. These are:
a) load resonance frequency f0 (CL = 20 pF) = 4.433619 or 3.579545 MHz
b) motional capacitance CM = 20.6 fF (4.43 MHz crystal) or (3.58 MHz crystal)
c) parallel capacitance C0 = 5.5 pF (4.43 MHz crystal) or 4.5 pF (3.58 MHz crystal).
The actual load capacitance in the application should be CL = 18 pF to account for parasitic capacitances on
and off chip.
The free-running frequency of the oscillator can be checked by pulling the saturation control pin to the positive supply
rail. In that condition the colour killer is not active so that the frequency off-set is visible on the screen. When two
crystals are connected to the IC the circuit must be forced to one of the crystals during this test to prevent the
oscillator continuously switching between the two frequencies.
38. In the TDA8362 the hue control pin has a double function. When the control voltage has a value of 0 to 5 V (normal
control range) the hue can be controlled when NTSC signals are decoded. When this voltage is increased to a value
greater than 5.5 V the decoder is forced to the PAL standard. When this pin is connected to the positive supply line
via a 10 kΩ resistor the selected CVBS signal, of the CVBS switch, is available. This signal can be applied to the
SECAM decoder TDA8395.
The phase shift of the hue control can be measured at the colour difference outputs (pins 30 and 31).
39. The −(R−Y) and −(B−Y) signals are demodulated with the 90° phase difference of the reference carrier and a gain
ratio −(B−Y)/−(R−Y) = 1.78. The matrixing to the required signals is achieved in the control part.
40. This value indicates the bandwidth of the complete chrominance circuit including the chrominance bandpass filter.
The bandwidth of the demodulator low-pass filter is approximately 1 MHz.
41. The reference signal for the TDA8395 is available only when the crystal oscillator is operating at a frequency of
4.43 MHz. When a SECAM signal is identified this signal is only available during the vertical retrace period thus
avoiding crosstalk with the incoming SECAM signal during scan.
42. When one of the three output signals exceeds this level the gain of the amplifiers is reduced. This is achieved by a
reduction of contrast and thus avoids clipping of the output signals. The discharge current at pin 25 is 0.2 mA. When
the black level exceeds a value of 2 V the maximum peak-to-peak value of the video output signal will be less than
4 V (p-p); this is due to the operation of the peak-white limiter.
43. The signal-to-noise ratio is specified as a peak-to-peak signal with respect to RMS noise (bandwidth 5 MHz). During
the measurement the peaking control voltage is set to nominal.
44. The typical free running frequency is dependent on the crystal which is used for calibration. With 4.4 MHz the typical
free running frequency is 15625, with 3.58 MHz the typical free running frequency is 15734.
Calibration during start-up is always carried out with a 4.4 MHz crystal if no forced mode is used.
March 1994
26
NXP [ NXP ]
