CP/PC364 Data Communications & Networks Laboratory

PRELAB

The following two weeks we will investigate Frequency Modulation and Demodulation. Using the XR-2207 and XR-2212 datasheets (provided below) determine the following and record in your lab notebook:

NOTE: The supply voltages must be the same for both ICs

Frequency Modulation

  1. Using the XR-2207 datasheet sketch a circuit for frequency sweep
    • determine what timing capacitor and timing resistor (R3) to use for a frequency of 10 Hz (refer to table 1)
    • let RC = R3
  2. Determine which pin of the 2207 is used for the input wave.

Frequency Demodulation

  1. Using the XR-2212 datasheet find and sketch a circuit that will take your frequency modulated signal (from the 2207) and demodulate it .
    • where does the incoming modulated signal (from the 2207) connect to the 2212 for demodulation?
  2. Determine R0, R1, Rc, Cf, C0 and C1 using the design instructions on the datasheet (pages 10, 11 & 12).
  3. Write down all the parts you will need (chips, resistors, capacitors, # of alligator clips, # of scope probes)

Datasheet: XR2207 [Copyright 1975 EXAR Corporation. Datasheet June 1997]
Datasheet: XR2212 [Copyright 1979 EXAR Corporation. Datasheet June 1997]

Table 1: Available Parts
Power Supplies Resistors (Ω) Variable
Resistors (Ω)		 Capacitors (μF)
GND (0V) 10 1k 500 0.001 0.01
+5V 3.9k 4.7k 10k 0.033 0.047
+12V 5.1k 10k 20k 0.1 0.22
-12V 20k 51k 50k 0.33 0.47
  100k 1M   1 10