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

This is measured using a Demodulator in B/G

and an 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

++

()

⁄

=