MC44BC375UAD Просмотр технического описания (PDF) - Freescale Semiconductor

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MC44BC375UAD

PLL Tuned VHF (Channel 3 / 4) Audio / Video Modulator

Freescale Semiconductor 

CHARACTERIZATION MEASUREMENT CONDITIONS

Device default configuration unless otherwise specified:

• Sound subcarrier frequency = 5.5 MHz

• Picture-to-sound carrier ratio = 14 dB

• CH3 and CH4 frequencies

• RF Inputs / Output into 75 Ω Load using a 75 to 50 Ω

transformation

• Video Input 1.0 V pk-pk

• Audio pre-emphasis circuit engaged

Table 9. Performance Measurement Test Set-Ups

Device and Signals Set-Up

Measurement Set-Up

Video: 10 steps grey scale

No audio

Video: 10 steps grey scale

No audio signal

RFOUT Output Level

Measured picture carrier in dBµV with the HP8596E Spectrum Analyzer using a

75 to 50 Ω transformation, all cables losses and transformation pads having been

calibrated.

Measurement is used as a reference for other tests: RFout_Ref

Sound Subcarrier Harmonics

Measure in dBc second and third sound harmonics levels in reference to picture

carrier (RFout_Ref).

Picture carrier

Sound carrier

Sound

2nd harm

Sound

3rd harm

Fo +5.5 MHz +11 MHz +16.5 MHz

Second Harmonics of Chroma Subcarrier

No audio

Video: a 700 mV(pp) 100 kHz sinusoidal

signal is inserted on the black level of active

video area.

Measure in dBc, in reference to picture carrier (RFout_Ref), second harmonic of

chroma at channel frequency plus 2 times chroma frequency, resulting in the

following spectrum.

Picture carrier

Frequency

Frequency

101000kkHHz z

700 mVpkpk

700mV pk-pk

Chroma

carrier

Sound

carrier

Chroma 2nd

Harmonic

Fo

+4.43 MHz +5.5 MHz

+8.86 MHz

MC44BC375U

8

Application Specific Products

Freescale Semiconductor

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