SL6649-I ZARLINK [Zarlink Semiconductor Inc], SL6649-I Datasheet - Page 10

• Manufacturer Part Number: SL6649-I
• Description: 200MHz DIRECT CONVERSION FSK DATA RECEIVER
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

METHOD FOR THE MEASUREMENT OF SENSITIVITY ON THE SL6649-1 RECEIVER
described in the CEPT Res 2 Specification.
by the insertion of a high value resistor R1 (100KΩ) between the receiver data output and the decoder input.
output level is then recorded as the sensitivity threshold of the receiver.
a B.E.R. of 1 in 30 and for input levels 2dB above and below this level, are shown below (square wave input). It can be seen that
the edge jitter increases dramatically at signal levels below the sensitivity threshold of -127dBm. Typical waveforms that can be
seen on an oscilloscope around the sensitivity threshold level are shown in Figure 12.
The method used by GEC Plessey Semiconductors in the measurement of terminal sensitivity is essentially the same as that
This method requires the following equipment:
1. A signal generator e.g. HP8640
2. A pocsag encoder
3. A pocsag decoder e.g. MV6639
4. An SL6649-1 Demo Board.
5. An interference free low impedance P.S.U. (V
The test equipment and D.U.T. are set up as shown in Figure 11.
The R.F. frequency is set to the nominal L.O. frequency of the receiver and the peak deviation is set to 4.5kHz.
Care must be taken to avoid long power supply leads and any ground loops. Any interference from the decoder will be reduced
The generator output level is reduced successively until the decoder responds just 4 out of 5 times to the encoder signal. This
We find that this threshold correlates to a bit error rate of 1 in 30. The data output waveforms for an input level which produces
NB. In performing the sensitivity measurement great care should be taken in preventing coupling between test leads.
difference between them). Recommended supply configurations are shown in Fig. 13.
Figure 12: Waveform at Data O/P
CC
Figure 11: Test System
1 and V
CC
2 must be separate supplies and there must be at least 0.7V
SL6649-1
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