Modulator Description

MC44BC373C/374C Technical Data

13 Modulator Description

13.1 Power ON Settings

At power-ON, the MC44BC373C/4C configuration is as follows:

These settings can be customized in special masked version.

13.2 Power Supply

The three device Vccs (pins 10, 13, 15) must be applied at the same time to ensure all internal blocks are

correctly biased. All other pins must not be biased before Vcc is applied to device.

13.3 Standby modes

During standby mode, the modulator is switched to low power consumption: the sound oscillator, UHF

oscillator, video and sound modulator sections bias are internally turned OFF.

The IIC bus section remains active.

Modulator can be programmed in standby mode with combination of 3 bits:OSC=1, SO=1 and ATT=1

13.4 System L or B / G Selection

SYSL bit internally switches the following functions:

•

SYSL = 0 enables B/G system

— Video modulation polarityNegative

— Video modulation depth80% Typical (See “Video Characteristics” on page 10.)

— Sound modulation typeFM

•

SYSL = 1 enables L system

— Video modulation polarityPositive

— Video modulation depth90% Typical (See “Video Characteristics” on page 10.)

— Sound modulation typeAM

WRITE MODE

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

ACK

C1—High Order Bits

10000000

ACK

C0—Low Order Bits

00001000

ACK

FM—High Order Bits

0

0

N11

N10

N9N8N7N6

ACK

FL—Low Order Bits

N5

N4

N3

N2

N1

N0

0

0

ACK

Note:

N0 to N11 are set to have UHF oscillator on channel 36 ( 591.25MHz).

Note:

Peak White Clip is ON.

Note:

Sound frequency is 5.5MHz.

Note:

Logic Output Port is low voltage.

Note:

Picture to sound ratio is 12dB.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com