PASCO WA-9318 User manual

Instruction Sheet
for the PASCO
Model WA-9318
MICROWAVE MODULATION KIT
012-02960D
12/03
SCOPE
9VDC
GUNN
MICROWAVE
MODULATOR
PASCO
scientific
Microwave
Transmitter
MODEL WA-9318
MICROWAVE
MODULATOR
FREQ
0.4 - 4 KHZ AMPL
BIAS
DIODE
MIC
Plug in for audio input.
Unplug for triangular
wave input.
9 V Power Adapter:
Plug into 120 VAC,
60 Hz outlet.
MICROPHONE
Microwave
Receiver
Top View
Bottom View
ON OFF
ON-OFF
Switch
Battery
Compartment
Introduction
The WA-9318 Microwave Modulation Kit turns your
PASCO Microwave Transmitter and Receiver into a
microwave communications system. Talk into the
microphone and your voice modulates the amplitude of
the transmitted microwaves, sending the signal
through space to the receiver. You can monitor the
signal at the modulator using an oscilloscope. The
signal at the receiver can also be monitored with an
oscilloscope, or you can use an audio amplifier and
speaker to provide an audible output. (The oscillo-
scope, amplifier, and speaker are not provided.)
For more quantitative investigations, the modulator
provides a triangular wave output with variable
frequency (0.4 - 4 kHz), amplitude (0 - 6 V peak-to-
peak), and bias (a DC offset to demonstrate "clip-
ping"). Using this triangular wave with an amplifier
and speaker, you can add an audible output to your
standard microwave experiments—a useful addition to
class demonstrations.
Equipment
Your WA-9318 Microwave Modulation Kit
includes (see above):
1. Microwave Modulator
*2. Microphone
3. Adapter Plugs
* Microphone: low impedance, 50-15,000 Hz fre-
quency response (replacement battery = 1.5 V
Eveready A76 or equivalent)
Adapter Plug

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!
Additional Equipment Needed:
*4. PASCO Microwave Transmitter
*5. PASCO Microwave Receiver
*6. 9 V Power Adapter
7. an oscilloscope, or an audio amplifier and
speaker, to monitor the output.
8. Banana plug connectors. (between the oscil
loscope and the modulation)
*Items 4-6 are provided in the PASCO Microwave
Optics System (WA-9314B or WA-9316)
Operation
Set up the equipment as shown in the preceding
illustration. Turn on the microphone with the ON/OFF
switch found on the microphone battery compartment.
Point the Microwave Transmitter toward the Micro-
wave Receiver. Then:
•To monitor the modulating signal, plug your os-
cilloscope into the banana plug connectors labeled
SCOPE on the Microwave Modulator. (see Fig-
ure)
•To monitor the signal at the receiving end, plug
your oscilloscope or audio amplifier w/speaker
(not included) into the banana plug connectors
labeled OUTPUT on the top of the Microwave
Receiver. (see Figure)
•If you wish to modulate the microwaves with the
triangular wave signal, unplug the microphone.
Adjust the frequency, amplitude, and bias of the
modulating signal using the controls on the Mi-
crowave Modulator. (The BIAS control adjusts
the DC voltage level of the Gunn Diode in the
Microwave Transmitter. The modulating signal
then varies the Gunn Diode voltage about this
DC voltage. Proper adjustment of the BIAS is
necessary to produce a linear, unclipped micro-
wave signal from the Gunn diode.)
Experiments
1. ADDING AN AUDIBLE OUTPUT TO MICRO-
WAVE EXPERIMENTS
The impact of most microwave experiments can be
improved by adding an audible output. The
maxima and minima of an interference pattern, for
example, seem somehow more real when they can
be heard in the variations in loudness of an audible
tone, instead of just seen as fluctuations in a meter
reading.
Any of the experiments in the manual that accom-
panied your PASCO Microwave Optics System can
be performed with an audible output. Just follow
the instructions listed above for using the triangular
wave output of the Modulator with an audio ampli-
fier and speaker.
2. MICROWAVE COMMUNICATIONS
With the simultaneous use of an oscilloscope and
an audio amplifier and speaker, this system is ex-
cellent for demonstrating microwave communica-
tions. The input signal can be the triangular wave
output of the modulator, or it can come from the
microphone or even a tape player.
Typical View of Dual Trace Oscilloscope
Typical Equipment Settings
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CH. 1 (Microwave Modulator)
CH. 2 (Receiver)
Modulator Receiver

012-002960D
3!
Schematic WA-9318
(Drawing No.956-02857)

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!
Equipment Return
Should this product have to be returned to PASCO
scientific, for whatever reason, notify PASCO scien-
tific by letter or phone BEFORE returning the product.
Upon notification, the return authorization and ship-
ping instructions will be promptly issued.
NOTE: NO EQUIPMENT WILL BE AC-
CEPTED FOR RETURN WITHOUT AN
AUTHORIZATION.
When returning equipment for repair, the units must be
packed properly. Carriers will not accept responsibil-
ity for damage caused by improper packing. To be
certain the unit will not be damaged in shipment,
observe the following rules:
1. The carton must be strong enough for the item
shipped.
2. Make certain there is at least two inches of pack-
ing material between any point on the apparatus
and the inside walls of the carton.
3. Make certain that the packing material can not
shift in the box, or become compressed, thus let-
ting the instrument come in contact with the edge
of the box.
Address: PASCO scientific
10101 Foothills Blvd.
P.O. Box 619011
Roseville, CA 95661-9011
Phone: [phone]
FAX: [phone]
Limited Warranty
PASCO scientific warrants this product to be free from
defects in materials and workmanship for a period of
one year from the date of shipment to the customer.
PASCO will repair or replace, at its option, any part of
the product which is deemed to be defective in mate-
rial or workmanship. This warranty does not cover
damage to the product caused by abuse or improper
use. Determination of whether a product failure is the
result of a manufacturing defect or improper use by the
customer shall be made solely by PASCO scientific.
Responsibility for the return of equipment for warranty
repair belongs to the customer. Equipment must be
properly packed to prevent damage and shipped
postage or freight prepaid. (Damage caused by
improper packing of the equipment for return shipment
will not be covered by the warranty.) Shipping costs
for returning the equipment, after repair, will be paid
by PASCO scientific.