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PCD4440T

Analog voice scrambler/descrambler

Philips Electronics 

Philips Semiconductors

Analog voice scrambler/descrambler

Product specification

PCD4440T

7.2 Power supply (VDD, VSS)

The positive supply of the circuit (VDD) must meet the

voltage requirement as indicated in the characteristics.

To avoid undefined states of the device at power-on, an

internal reset circuit clears the logic. The power-on reset

has the highest priority; it blocks and resets the complete

circuit.

7.4 Splitting frequency and mode selection

Table 1 shows the input codes required to select the

various splitting frequencies, and the mute, transparent

and scramble/descramble modes. The codes form part of

the serial I2C-bus message input on the SDA line from the

microcontroller.

7.3 Oscillator (OSCI)

The time base for the PCD4440T is a 3.58 MHz input

signal which can be derived from the oscillator output

(OSCO) of Philips microcontroller families PCD33xxA or

PCF84CxxxA. Figure 4 shows the OSCI connection.

handbook, full pagewidth

PCD33xxA

PCF84CxxxA OSCO

MICROCONTROLLER

27 pF

OSCI PCD4440T

3.58 MHz

MGG731

Fig.4 OSCI (oscillator input) connection.

Table 1 Input data codes for splitting frequency and mode selection; note 1

D3

0

0

0

0

0

0

0

1

1

1

1

1

D2

0

0

0

1

1

1

1

0

0

0

0

1

D1

0

1

1

0

0

1

1

0

0

1

1

1

D0

1

0

1

0

1

0

1

0

1

0

1

1

HEX

01

02

03

04

05

06

07

08

09

0A

0B

0F

APPLICATION

Mute mode

Select fs

Select fs

Select fs

Select fs

Select fs

Select fs

Select fs

Select fs

Select fs

Transparent mode

Start scramble/descramble mode

Notes

1. Input codes other than shown in the table are not allowed.

2. Oscillator frequency = 3.58 MHz.

1996 Dec 20

7

fs(2) (Hz)

−

2 641

1 853

1 507

1 279

1 117

1 018

899

837

767

−

−

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