UAA3220 PHILIPS [NXP Semiconductors], UAA3220 Datasheet - Page 6

• Manufacturer Part Number: UAA3220
• Description: Frequency Shift Keying FSK/Amplitude Shift Keying ASK receiver
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
Data slicer
Data detection is provided by means of a level comparator
with adaptive slice reference. After the first data filter stage
the pre-filtered data is split into two paths. One passes the
second data filter stage and is fed to the positive
comparator input. The other path is fed to an integration
circuit with a large time constant in order to derive the
average value (DC component) as an adaptive slice
reference which is presented to the negative comparator
input. The internal buffer provides 13 dB AC voltage gain.
The adaptive reference allows to detect the received data
over a large range of noise floor levels. The integration
circuit consists of a simple RC low-pass filter with on-chip
resistors. The data slicer output is designed with internal
pull-up.
1999 Jan 22
handbook, full pagewidth
Frequency Shift Keying (FSK)/Amplitude
Shift Keying (ASK) receiver
(1) T
(2) T
(3) T
V RSSI
(V)
1.55
1.45
1.35
1.25
1.15
amb
amb
amb
10
-7
= 85 C.
= 27 C.
= 40 C.
10
-6
Fig.3 Level curve V
10
-5
RSSI
10
6
as a function of V
-4
RSSI buffer
The RSSI buffer is an amplifier with a voltage gain of 0 dB.
At FSK receive mode the RSSI output provides a field
strength indication. It has an output impedance of 10 k .
Figure 3 shows the level curve (RSSI curve) as a function
of the limiter input voltage (RMS value).
10
-3
LIN(rms)
(1)
(2)
(3)
.
10
-2
V LIN(rms) (V)
UAA3220TS
Product specification
MGM744
10
-1