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SQW.TXT
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1996-10-29
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11KB
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278 lines
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SQW v(2)
A simple Square Wave generator
with a simple PC alone
Murat AYDIN 1996
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Serial ports have either output or input capability. This
specifity constituted a base for make a simple square wave generator.
Neither external card nor another device was used in this generator.
A simple PC is enough for this purpose. Windows is not necessary too.
What you have in original package: 1. SQW.EXE, 2. SQW.TXT this
file 3. PULSE.COM Place the all in a directory.
WHAT CHANGED IN THIS VERSION ?
1. F3 and F4 keys were activated during the pulse generation,
2. Again, during the pulse generation, a visual presentation was provided
but static.
3. Pulse duration and inter-pulse time was restricted with 2.214.999.999 µs.
4. Minor screen design changed.
WHERE IS THE SQUARE WAVE?
When the program begun to generate the square wave, you will read the signal
from bellowing pins of serial ports (if the port is present). You have to
use a fitting connector to one of them. Do not make solder for safety
your I/O card.
GRND
° ° ° ° ° ┬ ° ° ° ° ° ° ° ° °
° ° ▀ ° ──┴── ° ° ° ° ° ° ° ▀ °
───
─
CAN I ADJUST FREQUENCY?
Yes. Either pulse duration (t1) or interpulse time (t2) are adjustable
from keyboard. So that, a described frequency can be provided from the port.
Volt .<---- T ---->.
│ . .
│ .- t1 - .
+12 V ┼∙∙∙∙∙┌──────┐ ┌───────┐
│ │ │ │ │
│ │ │ │ │
│ │ │ │ │
0 ┼────────────│──────│───────│────────────────────────────────>time
│ │ │ │
│ │ │ │
│ │ │ │
-12 V ┼∙∙∙∙∙∙∙∙∙∙∙∙└──────┘ └────>
│ - t2 -
│
WHAT IS THE FREQUENCY RANGE?
This is an actual question. The upper limit of frequency depends on CPU
speed of your machine. Both, t1 and t2 can be decreased up to 1 µsec.
Theoretically, this is equal to 0.5 MHz of square wave, but not always
this oscillation would be appeared in the port for all type of machines.
Particularly, 386 or 286 machines will not approve an upper frequency
than 100 KHz. Although, all TSR programs in RAM, must be removed in order
to obtain a high frequency because they always prevent to climbing to high
frequencies.
On the other hand, both, t1 and t2 can be enlarged up to
2.214.999.999 µsec (equal to 36.9 minutes).
In result, the frequency range varies from 0.00045 Hz to 500 KHz.
Particularly at high frequencies, it may be some differences between
those two:
1. the value(s) of t1 or t2 which you have input from keyboard and
2. the value(s) of t1 or t2 which you have read from oscilloscope.
This difference always remains to be constant, if any. Further, this
difference which appears particularly at high frequencies, is specific for
each machine. Under these conditions, you can describe this difference
for an individual system, then, you can consider this number while you
input the t1 and t2 values. However, most often, at low frequencies, there
is never difference between them.
Most often, any differences will not appear when t1 and t2 was
selected greater than 2 msec.
Also, it is a minor detail but, keyboard scan operations occur
between t1 and t2 time, for this reason, t2 time can be found longer than
that you have typed from keyboard.
HOW MANY PORTS CAN BE ACTIVATED AT THE SAME TIME?
Only one serial port is available even you have more than one. Your system
may have four or more serial ports, but you can select only one of the
ports present in order to obtain a described square wave.
CAN I ADJUST PEAK-TO-PEAK VOLTAGE?
No, this voltage depend on power supply voltage of your computer. It is
12 volts. However, you can make bellowing variations :
1. SELECTION OF POSITIVE PULSES:
When you put a diode to the current way, the signal will take
this shape:
Volt .<---- T ---->.
│ . .
│ .- t1 - .
+12 Vcc ┼∙∙∙∙∙┌──────┐ ┌───────┐ ┌───────
│ │ │ │ │ │
│ │ │ │ │ │
│ │ │ │ │ │
0 ┼────────────└──────┘∙∙∙∙∙∙∙└──────┘ ∙∙∙∙∙∙∙∙∙∙────────────────>time
│ - t2 -
2. SELECTION OF NEGATIVE PULSES:
When you put a diode to the current way in opposite direction,
the signal will take this shape:
Volt .<---- T ----> .
│ . .
│ . .
+12 Vcc ┼ ∙ ∙
│ ∙ ∙
│ ∙ - t2 - ∙
0 ┼────────────┌───────┐────────────────────────────────>time
│ │ │ │
│ │ │ │
│ │ │ │
-12 Vcc ┼∙∙∙∙∙└──────┘ └────>
│ - t1 - X
│
3. A FREQUENCY MULTIPLIER or DIVIDER can be added.
4. This signal can be changed to a SINE or TRIANGLE wave by
a simple electronic circuit can be added by user.
HOW MANY AMPERES CAN BE LOADED?
Approximately, 15-80 mA can be pulled. More much loadings may give damage
to I/O card of your system.
THE OUTPUT IMPEDANCE ?
In most machines, output impedance may alter between 2 kΩ to 34 kΩ.
NOISE OR DISTORTION IN THE SQW ?
For an ideal square wave, all angles are 90° (rise, delay and come-down).
With this software, you will usually provide the angles to be 90°.
However, the signal shape may be distorted briefly in only high frequencies.
When the signal was monitored by an osscilloscope, if the signal does not
seem to be a smooth line (as seen in the bellowing figure), particularly
pulse-duration section, you can decide that, the I/O card is not complete
acceptable for this purpose. Some machines make this.
┌── ┌── ┌───
│ \ │ \ │ \
│ \ │ \ │ \
│ \ │ \ │ \
\──────┘ \ ──────┘ \
CAN I MONITORIZE THE SIGNAL ON SCREEN DURING PULSE GENERATION ?
Perhaps in future versions may be yes, but not in this version. You can not
monitorize the signal present from your screen. Because, the mean of this
operation is the time-lose. However, an oscilloscope which was connected
to the actual port, can show the signal present.
MAY IT DESTROY THE I/O CARD?
No, this is highly safe method. However, avoid to make short-circuit between
tips of the port.
Instantaneous contacts have not a deleterious effect, if it does
not extent over one hour or more. Take your own risk, or, in order to protect
your I/O card, you can use a 1 kΩ (¼ W) of resistance with serially to the
out-put pin. This is not prerequisite.
A SESSION:
═════════
1. Run the SQW.EXE
2. If you have not an idea about the current ports, you can learn
which serial port(s) are available in your system. Select the 'scan ports'
and press <enter>. The program will give a report about active serial
ports and their addresses.
3. If you are starting first, select the 'workout' and mark one of
the serial ports. (This step can be ignored, if you have experiences about how
this program works.) And press <enter>. The program will send slow
pulses to the port which you have selected. On the other hand, you will hear
a double sound, bip-bep. Now, connect an AVO-meter or an oscilloscope to
the entailed pin of the selected port and the ground of your computer.
Every pulse must be monitored at the pin of the selected port. You must read
a pulsation which is synchronized to the double sound present.
At this stage, you can provide a faster or slower pulsation with use
Page Up or Page Down keys respectively. Exit from this sub-menu with <Esc>,
if you have found the actual pin. Turn off the system, make a good connection
to the port. Turn on again.
4. Select the 'describe' sub-menu, press <enter>. Answer the questions
about t1 and t2 values. These values must be a positive number between 1 and
2214999999, but as to be microsecond. Do not use comma, semicolon, space i.e.
Then, input which you want to use serial port. And, press 'y'es for begin.
The given data will be checked by the program. If there is a problem,
it will give an alert message else, it will jump to PULSE.COM which must be
present in the original zip file.
5. PULSE.COM does not work without SQW.EXE. When the PULSE.COM run by
SQW.EXE, the given data will be re-checked. Press any key for start to
sending. You can use these:
<F1>, make pause
<F2>, reverses the signal present. In other words, the t1 and t2
values will be swapped by <F2> function.
<F3>, t1 value will be increased one micro-second
<F4>, t2 value will be increased one micro-second
Note: If you swapped the t1 and t2 values,
and if you have requested an increment in t1
time, always the new t1 time will be increased
but not old t1 time.
<Esc>, stop the signal generation and exit.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
This program can be distributed by FREE OF CHARGE. When /if you need
to the source files of newest version, send $30 and a message to me
via E-mail.
All comments and suggestions are welcome. Please send your
comments and suggestions to the address below or e-mail them to:
Murat AYDIN, Ph. D. Dent.
Department of Microbiology,
Faculty of Medicine,
Çukurova Üniversity
Adana - TÜRKÿYE
E-mail: muratay@pamuk.cc.cu.edu.tr
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