
Application Specific Products
Freescale Semiconductor
11
MC44BC375U
Video Modulation Depth
No audio signal
Video: 10 step grey scale
This is measured using a HP8596E Spectrum Analyzer with a TV Trigger option,
allowing demodulation and triggering on any specified TV Line. The analyzer is
centered on the maximum peak of the Video signal and reduced to zero Hertz
span in Linear mode to demodulate the Video carrier.
The Modulation Depth is calculated as (A-B)/A x 100 in%.
Picture to Sound Ratio
No video signal
No audio Signal
“PSS” pin set Low and High
Measure in dBc sound carrier in reference to picture carrier (RFout_Ref) for
“PSS” = Low (PS = 14 dB typical) and for “PSS” = High (PS = 16 dB),
Audio Modulation Depth — FM Modulation
Video Black Level
Audio signal: 1.0 KHz, 205 mVrms.
This is measured using a Demodulator in B/G
and an Audio Analyzer at 1.0 KHz.
The audio signal 205 mV at 1.0 KHz is supplied by the Audio Analyzer, and the
FM demodulated signal deviation is indicated on the Demodulator in KHz peak.
This value is then converted in% of FM deviation, based on specified standards.
Audio Frequency Response
Video Black Level
Audio signal: 50 Hz to 15 KHz, 100 mVrms
This is measured using a Demodulator in B/G
and an Audio Analyzer.
The audio signal 1.0 KHz 100 mVrms is supplied by the Audio Analyzer,
demodulated by the Demodulator and the audio analyzer measures the AC
amplitude of this demodulated audio signal: this value is taken as a reference
(0 dB).
The audio signal is then swept from 50 Hz to 15 KHz, and demodulated AC
amplitude is measured in dB relative to the 1.0 KHz reference.
Audio pre-emphasis and de-emphasis circuits are engaged, all audio analyzer
filters are switched OFF.
Audio Distortion FM
Audio: 1.0 KHz, adjustable level
Video Black Level
This is measured using a Demodulator in B/G
and an Audio Analyzer at 1.0 KHz. The output
level of the Audio analyzer is varied to obtain
a deviation of 50 KHz indicated on the
Demodulator.
The input rms detector of the Audio Analyzer converts the ac level of the
combined signal + noise + distortion to dc. It then removes the fundamental
signal (1.0 KHz) after having measured the frequency. The output rms detector
converts the residual noise + distortion to dc. The dc voltmeter measures both
dc signals and calculates the ratio in% of the two signals.
Table 9. Performance Measurement Test Set-Ups (continued)
Device and Signals Set-Up
Measurement Set-Up
A ( 6-10mV)
B (0.6 - 3mV)
TV Line Demodulated by Spectrum Analyzer-BG standard
A(mV)
B(mV)
Picture carrier
Sound carrier
+5.5 MHz
Fo
ADist
Distorsion
Noise
+
() Distorsion Noise Signal
++
()
=