MC13156 Datasheet, PDF (17/20 Pages) Motorola, Inc – Wideband FM IF System

MC13156
BER TESTING AND PERFORMANCE
Description
The test setup shown in Figure 31 is configured so that the
function generator supplies a 100 kHz clock source to the bit
error rate tester. This device generates and receives a
repeating data pattern and drives a 5 pole baseband data
filter. The filter effectively reduces harmonic content of the
baseband data which is used to modulate the RF generator
which is running at 144.45 MHz. Following processing of the
signal by the receiver (MC13156), the recovered baseband
sinewave (data) is AC coupled to the data slicer. The data
slicer is essentially an auto–threshold comparator which
tracks the zero crossing of the incoming sinewave and
provides logic level data at its ouput. Data errors associated
with the recovered data are collected by the bit error rate
receiver and displayed.
Bit error rate versus RF signal input level and IF filter
bandwidth are shown in Figure 30. The bit error rate data was
taken under the following test conditions:
• Data rate = 100 kbps
• Filter cutoff frequency set to 39% of the data rate or 39 kHz.
• Filter type is a 5 pole equal–ripple with 0.5° phase error.
• VCC = 4.0 Vdc
• Frequency deviation = ±32 kHz.
Figure 30. Bit Error Rate versus RF
Input Signal Level and IF Bandpass Filter
10 ^–1
10 ^–3
IF Filter BW
110 kHz
VCC = 4.0 Vdc
Data Pattern = 2E09 Prbs NRZ
Baseband Filter fc = 50 kHz
fdev = ±32 kHz
10 ^–5
IF Filter BW
230 kHz
10 ^–7
–90
–85
–80
–75
–70
RF INPUT SIGNAL LEVEL (dBm)
Evaluation PC Board
The evaluation PCB is very versatile and is intended to be
used across the entire useful frequency range of this device.
The center section of the board provides an area for
attaching all SMT components to the circuit side and radial
leaded components to the component ground side (see
Figures 32 and 33). Additionally, the peripheral area
surrounding the RF core provides pads to add supporting
and interface circuitry as a particular application dictates.
Figure 31. Bit Error Rate Test Setup
Function Generator
Wavetek Model No. 164
Clock
Out
Gen
Clock
Input
Bit Error Rate Tester
HP3780A or Equivalent
Rcr
Rcr
Clock Data
Input Input
Generator
Input
RF Generator
HP8640B
Modulation
Input
RF
Output
5 Pole
Bandpass
Filter
Data Slicer
Output
Mixer
Input
MC13156
UUT
MOTOROLA WIRELESS SEMICONDUCTOR
17
SOLUTIONS – RF AND IF DEVICE DATA