background image

AF1 

 14  

ˆ

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. 

ˆ

Set switches S2 and S3 in the “out” position for maximum bandwidth. 
Push in switch S1 to energize the circuit. 

ˆ

Adjust R14 for the proper volume level. 

ˆ

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.  

ˆ

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 

Содержание AF1 CW AUDIO FILTER

Страница 1: ...t Utilizes state of the art switched capacitor bandpass filter IC s Four selectable bandwidths 750 Hz 500 Hz 250 Hz and 100 Hz all with digital accuracy Adjustable filter center frequency for convenie...

Страница 2: ...ce Meter RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MI...

Страница 3: ...5 Parts list 6 AF1 Assembly instructions 8 Schematic diagram 10 Parts Layout diagram 11 Hook up configurations 13 Troubleshooting 14 Ramsey kit warranty 15 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR RAMS...

Страница 4: ...ter the received audio to only allow a single CW tone to be heard That s where the Ramsey AF1 filter comes in to help The audio filter board creates an audio frequency bandpass filter to remove the un...

Страница 5: ...ascaded to provide sharper filter characteristics a Q LOGIC binary input to set the filter bandwidth an adjustable internal oscillator to provide the center frequency for our filter and an extra op am...

Страница 6: ...8 3 100K ohm resistors brown black yellow R5 6 12 1 750K ohm resistor violet green yellow R2 1 49 9K ohm resistor yellow white white red R7 1 147K ohm resistor brown yellow violet orange R9 1 294K oh...

Страница 7: ...steps First we install parts in physical relationship to each other so there s minimal chance of inserting wires into wrong holes Second whenever possible we install in an order that fits our Learn A...

Страница 8: ...dphone jack Notice the seven pins protruding from the bottom of the component Be sure that none of these connecting pins have been bent over before installing J2 Solder all connections Next we ll begi...

Страница 9: ...signals from the bottom to the top side of the circuit board and then back to the bottom side again 17 Grab some more scraps of leads form and install JMP2 3 4 Hey this is better than recycling if we...

Страница 10: ...cement diagram 26 In the same manner install diode D2 another 1N4148 Note that the polarity of this diode is reversed 27 Install C4 1 uF disc capacitor marked 1 or 104 28 Install R8 47K ohm yellow vio...

Страница 11: ...AF1 11 AF1 PARTS LAYOUT DIAGRAM...

Страница 12: ...sure to orient this end as shown in the parts diagram 38 Install C1 1 uF disc capacitor marked 1 or 104 39 Install R6 100K ohm brown black yellow 40 Install C6 10 uF electrolytic Check polarity when...

Страница 13: ...sure to orient the long lead as shown in the diagram The leads will slide through the holes on the top of the switch contacts Be sure to leave enough lead length on the diode so it can poke through th...

Страница 14: ...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 troub...

Страница 15: ...be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you b...

Страница 16: ...for RAMSEY MODEL NO AF1 CW AUDIO FILTER RAMSEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykits com REQUIRED TOOLS Soldering Iron WLC...

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