1997 Jan 15

8

Philips Semiconductors

Product specification

Programmable multi-tone telephone ringer

PCD3360

When IS1 and IS2 are both LOW, the circuit operates in

the automatic swell mode. The SPL then increases in three

steps so that the maximum level is reached for the third

ringing burst.

register is reset and the next ringing burst is considered as

N = 1 (see Table 4). A buffer capacitor (see Fig.8) must

ringing bursts of a series.

For each of the other three combinations of pins IS1 and

IS2 the pulse duration has a constant value. Thus the

ringer can be designed so that the impedance represented

at the telephone line will comply with postal requirements

that vary in relation to parallel or series connections of

more than one ringer.

To satisfy some applications, a harmonic signal is added

to the fundamental frequency in the last step of the

automatic swell mode. The pulses representing this

harmonic signal are interleaved with the pulses of the

fundamental signal (see Fig.7). The difference in pulse

duration shown in Table 4, is chosen so that the harmonic

level is 10 dB below the fundamental level.

The harmonic frequency range is from 2 kHz to 3.2 kHz.

The individual harmonic frequencies for the seven tone

codes and the relative fundamental frequencies are shown

in Table 5.

Table 5

Harmonic frequency in relation to tone code and

fundamental frequency

Using a single mask it is possible to program the following:

• Addition of harmonics in all the other input states of IS1

and IS2

• All pulse duration values

• Other even harmonic frequencies.

7.10

Optical output (OPT)

The OPT output is designed to drive an optical signal

transducer or lamp. It is LOW when the ringer circuit is

enabled and HIGH when the ringer circuit is disabled. This

output can also be used to switch the transmitter ON and

OFF in the base unit of a cordless telephone set.

TONE CODE

FREQUENCY (Hz)

FUNDAMENTAL

HARMONIC

1

533

3200

2

600

2400

3

667

2667

4

800

3200

5

1000

2000

6

1067

2133

7

1333

2667