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AF1 • 14
Connect an audio output device such as a speaker or headset to the
appropriate jack (J1 or J2, respectively). With switch S1 in the off
position you should be able to hear the tone under test.
Set switches S2 and S3 in the “out” position for maximum bandwidth.
Push in switch S1 to energize the circuit.
Adjust R14 for the proper volume level.
You can now experiment with your kit by
changing the tone frequencies with the audio
generator and following with the center
frequency adjustment of the AF1.
By changing the position of switches S2 and
S3 you can change the bandwidth of the audio
filter. The chart describes the switch/bandwidth
for the AF1.
You should be able to “hear” the differences in the bandpass filters. Try and
plot a few data points for frequency vs loudness and you should be able to
plot the different bandwidths. This is by no means an exact measurement but
it is impressive that this digitally controlled switched capacitance filter is
responding to your commands -and - you did it yourself!
TROUBLESHOOTING INSTRUCTIONS
While we had hoped that it wouldn’t come to this, if you’re having trouble with
your kit here are a few suggestions. Use a methodical trouble shooting
technique - a clear head and a voltmeter are all that are usually required to
correct any problem. Rest assured that both of the MF8 IC’s have been pre-
tested before they were included in your kit. More times than not a part in
the wrong place causes the problem, so ask a friend to check your work as
well. Try not to be discouraged, working backwards through the assembly
steps will usually lead you to the problem.
CONCLUSION
We sincerely hope that you have enjoyed the construction and use of this
Ramsey Kit. As always, we have tried to compose our manual in the easiest,
most “user friendly” format that is possible. As our customers, we value your
opinions, comments, and additions that you would like to see in future
publications. Please submit comments or ideas to:
Ramsey Electronics Inc.
Attn. Hobby Kit Department
590 Fishers Station Drive
Victor, NY 14564
And once again, thanks from the folks at Ramsey!
Bandwidth
(Hz)
S2 S3
100 IN IN
250 IN OUT
500 OUT IN
750 OUT OUT