mc44bc375u Freescale Semiconductor, Inc, mc44bc375u Datasheet - Page 11

• Manufacturer Part Number: mc44bc375u
• Description: Pll Tuned Vhf Channel 3 / 4 Audio / Video Modulator
• Manufacturer: Freescale Semiconductor, Inc

Application Specific Products
Freescale Semiconductor
Table 9. Performance Measurement Test Set-Ups (continued)
No audio signal
Video: 10 step grey scale
No video signal
No audio Signal
“PSS” pin set Low and High
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.
Video Black Level
Audio signal: 50 Hz to 15 KHz, 100 mV
This is measured using a Demodulator in B/G
and an Audio Analyzer.
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.
Device and Signals Set-Up
rms
Audio Modulation Depth — FM Modulation
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%.
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),
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.
The audio signal 1.0 KHz 100 mV
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.
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.
Audio Frequency Response
Video Modulation Depth
Picture to Sound Ratio
Audio Distortion FM
ADist
TV Line Demodulated by Spectrum Analyzer-BG standard
=
(
Distorsion
Picture carrier
Measurement Set-Up
+
Fo
Noise
rms
+5.5 MHz
is supplied by the Audio Analyzer,
)
⁄
Sound carrier
(
Distorsion
A(mV)
B(mV)
B (0.6 - 3mV)
A ( 6-10mV)
+
Noise
+
Signal
MC44BC375U
)
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