MC44BC375U Datasheet, PDF (11/16 Pages) Freescale Semiconductor, Inc – PLL Tuned VHF (Channel 3 / 4)Audio / Video Modulator

Table 9. Performance Measurement Test Set-Ups (continued)
Device and Signals Set-Up
Measurement Set-Up
No audio signal
Video: 10 step grey scale
Video Modulation Depth
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.
A(Am( 6V-1)0mV)
No video signal
No audio Signal
“PSS” pin set Low and High
B(_Bm_(0.V_{6 -})_3mV)
TV Line Demodulated by Spectrum Analyzer-BG standard
The Modulation Depth is calculated as (A-B)/A x 100 in%.
Picture to Sound Ratio
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),
Picture carrier
Sound carrier
Fo +5.5 MHz
Audio Modulation Depth — FM Modulation
Video Black Level
The audio signal 205 mV at 1.0 KHz is supplied by the Audio Analyzer, and the
Audio signal: 1.0 KHz, 205 mVrms.
FM demodulated signal deviation is indicated on the Demodulator in KHz peak.
This is measured using a Demodulator in B/G This value is then converted in% of FM deviation, based on specified standards.
and an Audio Analyzer at 1.0 KHz.
Audio Frequency Response
Video Black Level
The audio signal 1.0 KHz 100 mV_rms is supplied by the Audio Analyzer,
Audio signal: 50 Hz to 15 KHz, 100 mV_rms ^{demodulated by the Demodulator and the audio analyzer measures the AC}
This is measured using a Demodulator in B/G ^{amplitude of this demodulated audio signal: this value is taken as a reference}
and an Audio Analyzer.
(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
The input rms detector of the Audio Analyzer converts the ac level of the
Video Black Level
combined signal + noise + distortion to dc. It then removes the fundamental
This is measured using a Demodulator in B/G ^{signal (1.0 KHz) after having measured the frequency. The output rms detector}
and an Audio Analyzer at 1.0 KHz. The output ^{converts the residual noise + distortion to dc. The dc voltmeter measures both}
level of the Audio analyzer is varied to obtain ^{dc signals and calculates the ratio in% of the two signals.}
a deviation of 50 KHz indicated on the
Demodulator.
ADist = (Distorsion + Noise) ⁄ (Distorsion + Noise + Signal)
Application Specific Products
Freescale Semiconductor
MC44BC375U
11