1997 Jan 15
7
Philips Semiconductors
Product specification
Programmable multi-tone telephone ringer
PCD3360
7.7
Selection of repetition rates (RR1 and RR2)
The duration of a time interval within a tone sequence is
determined by the state of inputs RR1 and RR2 as shown
in Table 3. The resultant variation of repetition rates acts
as a distinguishing feature between adjacent telephones.
Table 3
Duration of time intervals (f
OSC
= 64 kHz)
The repetition rate variation can be extended by mask
programming the same tone combination for all 4 tone
sequences, but with a different number of time intervals
per tone. Thus the repetition rate can be selected from
16 values by inputs RR1, RR2, TSI and TS2. The single
tone sequence used is customer-defined.
INPUT STATE
TIME INTERVAL
(ms)
RR1
RR2
LOW
LOW
HIGH
HIGH
LOW
HIGH
LOW
HIGH
15
30
45
60
7.8
Drive mode selection (DM)
The output signal at pin TONE can be selected for
application with electro-dynamic or piezo-electric
transducers. An example of both signals, for a tone
frequency of 667 Hz, is shown in Fig.6.
7.8.1
L
OUDSPEAKER MODE
In the loudspeaker mode (DM = LOW), pin TONE outputs
a delta-modulated signal that approximates a sinewave
sampled at a rate of 32 kHz. The output pulse duration is
determined by pins IS1 and IS2. The resultant acoustic
spectrum is aurally more acceptable and has greater
penetration than a square-wave spectrum because more
power is concentrated at the fundamental frequency.
7.8.2
PXE
MODE
In the PXE mode (DM = HIGH), pin TONE outputs a
square wave. In this mode the ringer impedance and
sound pressure level are determined by characteristics
(e.g. the size) of the PXE transducer; inputs IS1 and IS2
are inactive.
7.9
Setting of impedance, sound pressure level and automatic swell (IS1 and IS2)
With DM = LOW (loudspeaker mode), inputs IS1 and IS2 determine the pulse duration of the output signal and thereby
the DC resistance R
xy
(seen at points x and y in Fig.8), the input impedance Z
i
and also the Sound Pressure Level (SPL).
The selection of 3 impedance settings and automatic swell is shown in Table 4.
Table 4
Setting of pulse duration and automatic swell (DM = LOW)
Notes
1.
Typical pulse durations, t
fund
and t
harm
, for the delta-modulated approximation of fundamental and harmonic signals;
valid for f
OSC
= 64 kHz and f
clk
= 32 kHz. See Fig.6 and Fig.7.
SPL is the relative Sound Pressure Level, and 0 dBr is defined as the SPL for IS1 = IS2 = HIGH.
Values of the DC resistance R
xy
, bell impedance (Z
i
) and SPL are valid for a value of input voltage V
i(rms)
= 40 V.
2.
3.
INPUT STATE
FUNCTION
RINGING
BURST
NUMBER (N)
PULSE
DURATION
(1)
(
μ
s)
R
xy
(3)
(k
)
Z
i
(3)
(k
)
SPL
(2)(3)
(dBr)
IS1
IS2
t
fund
1.9
2.9
4.1
2.9
3.8
5.4
t
harm
1.8
LOW
LOW
automatic swell
1
2
40
20
5
20
10
5
tbf
17.5
7
17.5
10.5
7
tbf
4
0
4
tbf
0
>2
LOW
HIGH
HIGH
HIGH
LOW
HIGH
constant level