HC-55564
Figures 4, 5, and 6 illustrate the typical frequency
response of the HC-55564 for varying input levels and for
varying sampling rates. To prevent slope overload (slew
limiting), the 0dB boundary should not be exceeded. The
frequency response is directly proportional to the sampling
clock rate. The flat bandwidth at 0dB doubles for every
doubling in sampling rate. The output levels were mea-
sured in the encode mode, without filtering, from A
IN
to
A
OUT
, at V
DD
= 5V. 0dB = 1.2V
RMS
.
A
OUT
A
IN
0dB = INPUT SIGNAL LEVEL
-6dB
-12dB
-20
-24dB
-30dB
-36dB
-40
dB
-30
1000
INPUT FREQUENCY AT A
IN
(Hz)
10000
-18dB
-10
100
FIGURE 4. 16kbps
A
OUT
A
IN
0dB = INPUT SIGNAL LEVEL
-6dB
-12dB
dB
-30
-40
1000
INPUT FREQUENCY AT A
IN
(Hz)
10000
-18dB
-24dB
-30dB
-36dB
-20
-10
100
FIGURE 5. 32kbps
A
OUT
A
IN
0dB = INPUT SIGNAL LEVEL
-6dB
-12dB
-20
dB
-30
-40
1000
INPUT FREQUENCY AT A
IN
(Hz)
10000
-18dB
-24dB
-30dB
-36dB
-10
100
FIGURE 6. 64kbps
5
HARRIS [ HARRIS CORPORATION ]
