help w/testing oscope looking at variety of signals

R

robb

Guest
I (hobbyist) was trying out the new (to me) oscope ( tek 2236 )
by trying a suggestion of looking at various waveforms from
different equipment around the house , clock
radio/oscilators/crystals/wall-wart etc.

i decided to crack open the $5 - 49.86 MHz remote control
transmitter and sample the 49.86 MHz crystal and i was wondering
what i should expect to see ?

it appears to be (in the best viewing case) a 49.86 MHz sine wave
about 2.4 volts.
i say 49.86 because the DMM displays that as frequency (as does
crystal pkg)

however with diff oscope settings and adjustments there appears
to be either a simultaneous super-imposed wave just slightly
lower amplitude (.3v) and slightly less than sine like , maybe
flatter and the peaks a little wider like a squashed sine wave ?
then yet another setting i get what appears to be 3 or 4 of the
sine waves super imposed all same magnitude with a slight horiz
offset (1/10 of 1 graticule division) but they appear to be
intertwined and kind of dancing in tight circle where it appears
(3d'ish) the waves undulate toward/away (dimmer and brighter
while moving appears to move toward ) very slight but
perceptable to my eye fairly easily.


is there a typicle way that data is sent with simpl 4 button 49
MHz remote transmitter ?
just wondering what i should expect to see when pressing a
button.

thanks for any info
robb
 
robb wrote:
I (hobbyist) was trying out the new (to me) oscope ( tek 2236 )
by trying a suggestion of looking at various waveforms from
different equipment around the house , clock
radio/oscilators/crystals/wall-wart etc.

i decided to crack open the $5 - 49.86 MHz remote control
transmitter and sample the 49.86 MHz crystal and i was wondering
what i should expect to see ?

it appears to be (in the best viewing case) a 49.86 MHz sine wave
about 2.4 volts.
i say 49.86 because the DMM displays that as frequency (as does
crystal pkg)

however with diff oscope settings and adjustments there appears
to be either a simultaneous super-imposed wave just slightly
lower amplitude (.3v) and slightly less than sine like , maybe
flatter and the peaks a little wider like a squashed sine wave ?
then yet another setting i get what appears to be 3 or 4 of the
sine waves super imposed all same magnitude with a slight horiz
offset (1/10 of 1 graticule division) but they appear to be
intertwined and kind of dancing in tight circle where it appears
(3d'ish) the waves undulate toward/away (dimmer and brighter
while moving appears to move toward ) very slight but
perceptable to my eye fairly easily.


is there a typicle way that data is sent with simpl 4 button 49
MHz remote transmitter ?
just wondering what i should expect to see when pressing a
button.
Click to expand...
The most important skill in seeing anything clearly on a
scope is triggering. This is the mechanism that holds the
trace till some recognizable and repeating part of the
waveform occurs. If you trigger the sweep from the same
place in a repeating wave, all the copies that you see will
overlap precisely, and you will have a crisp, stable view.

The two basic modes for the triggering process are Normal
and Auto. Normal mode holds the sweep, indefinitely, till
the defined trigger conditions are met. Auto mode will hold
the sweep for a while, waiting for the trigger conditions to
be met, but will time out several times a second, just so
you can see where the trace is. I'll bet you have yours set
to Auto mode and it is not actually triggering on any part
of the observed waveform.

After you have chosen Normal or auto, you have lots of
choices as to what a trigger condition is. First you choose
its signal source (channel 1 or 2, the power line, or the
external trigger input jack). Then you pick a direction,
rising or falling. Then you decide if you want the trigger
signal to be filtered (some choices might be high frequency
noise filtering, video horizontal or vertical frequency
ranges or no filter). Then you adjust the trigger level,
till it intersects your waveform. I think your scope shows
you a little arrow along the right edge of the screen that
shows you where the level is set if you choose channel 1 or
2 as the trigger signal source. Fiddling around with the
level, and maybe the filter choices you should be able to
lock in on almost any repeating waveform.
 
"robb"

is there a typicle way that data is sent with simpl 4 button 49
MHz remote transmitter ?
just wondering what i should expect to see when pressing a
button.
Click to expand...

** Usually, the output of the transmitter is simply turned on and off with
some type of pattern that identifies which button.

Turn your scope to a slow time base ( like 50mS / division) so you can see
this pattern.

Usually no direct connection to the device is needed, just make a loop with
the probe and earth clip, fit it around the unit and find the best location.


......... Phil
 
On Oct 20, 8:27 pm, John Popelish <jpopel...@rica.net> wrote:
robb wrote:
I (hobbyist) was trying out the new (to me) oscope ( tek 2236 )
by trying a suggestion of looking at various waveforms from
different equipment around the house , clock
radio/oscilators/crystals/wall-wart etc.

i decided to crack open the $5 - 49.86 MHz remote control
transmitter and sample the 49.86 MHz crystal and i was wondering
what i should expect to see ?

it appears to be (in the best viewing case) a 49.86 MHz sine wave
about 2.4 volts.
i say 49.86 because the DMM displays that as frequency (as does
crystal pkg)

however with diff oscope settings and adjustments there appears
to be either a simultaneous super-imposed wave just slightly
lower amplitude (.3v) and slightly less than sine like , maybe
flatter and the peaks a little wider like a squashed sine wave ?
then yet another setting i get what appears to be 3 or 4 of the
sine waves super imposed all same magnitude with a slight horiz
offset (1/10 of 1 graticule division) but they appear to be
intertwined and kind of dancing in tight circle where it appears
(3d'ish) the waves undulate toward/away (dimmer and brighter
while moving appears to move toward ) very slight but
perceptable to my eye fairly easily.

is there a typicle way that data is sent with simpl 4 button 49
MHz remote transmitter ?
just wondering what i should expect to see when pressing a
button.

The most important skill in seeing anything clearly on a
scope is triggering. This is the mechanism that holds the
trace till some recognizable and repeating part of the
waveform occurs. If you trigger the sweep from the same
place in a repeating wave, all the copies that you see will
overlap precisely, and you will have a crisp, stable view.

The two basic modes for the triggering process are Normal
and Auto. Normal mode holds the sweep, indefinitely, till
the defined trigger conditions are met. Auto mode will hold
the sweep for a while, waiting for the trigger conditions to
be met, but will time out several times a second, just so
you can see where the trace is. I'll bet you have yours set
to Auto mode and it is not actually triggering on any part
of the observed waveform.

After you have chosen Normal or auto, you have lots of
choices as to what a trigger condition is. First you choose
its signal source (channel 1 or 2, the power line, or the
external trigger input jack). Then you pick a direction,
rising or falling. Then you decide if you want the trigger
signal to be filtered (some choices might be high frequency
noise filtering, video horizontal or vertical frequency
ranges or no filter). Then you adjust the trigger level,
till it intersects your waveform. I think your scope shows
you a little arrow along the right edge of the screen that
shows you where the level is set if you choose channel 1 or
2 as the trigger signal source. Fiddling around with the
level, and maybe the filter choices you should be able to
lock in on almost any repeating waveform.
Click to expand...
Adding to John's excellent description of triggering: you'll probably
want to choose the Low Frequency Reject or "LF Rej" trigger option.
There could easily be some 60 Hz (or other) in your signal that can
make the trace dance around.

Mark
 
"John Popelish" <jpopelish@rica.net> wrote in message
news:ro6dnSeD9b18AYfanZ2dnUVZ_ruqnZ2d@comcast.com...
robb wrote:
[trimmed]
I (hobbyist) was trying out the new (to me) oscope ( tek
2236 )
by trying a suggestion of looking at various waveforms from
different equipment around the house , clock
radio/oscilators/crystals/wall-wart etc.

however with diff oscope settings and adjustments there
appears
to be either a simultaneous super-imposed wave

is there a typical way that data is sent with simpl 4 button
49
MHz remote transmitter ?

The most important skill in seeing anything clearly on a
scope is triggering. This is the mechanism that holds the
trace till some recognizable and repeating part of the
waveform occurs. If you trigger the sweep from the same
place in a repeating wave, all the copies that you see will
overlap precisely, and you will have a crisp, stable view.

having read that , i presume that scope quality/value/usefullness
Click to expand...
is directly proportional to the variety of user selectable
triggering options/settings ?
The two basic modes for the triggering process are Normal
and Auto. Normal mode holds the sweep, indefinitely, till
the defined trigger conditions are met. Auto mode will hold
the sweep for a while, waiting for the trigger conditions to
be met, but will time out several times a second, just so
you can see where the trace is. I'll bet you have yours set
to Auto mode and it is not actually triggering on any part
of the observed waveform.

yes, you are correct, in my case p-p auto

After you have chosen Normal or auto, you have lots of
choices as to what a trigger condition is. First you choose
its signal source (channel 1 or 2, the power line, or the
external trigger input jack). Then you pick a direction,
rising or falling. Then you decide if you want the trigger
signal to be filtered (some choices might be high frequency
noise filtering, video horizontal or vertical frequency
ranges or no filter). Then you adjust the trigger level,
till it intersects your waveform. I think your scope shows
you a little arrow along the right edge of the screen that
shows you where the level is set if you choose channel 1 or
2 as the trigger signal source. Fiddling around with the
level, and maybe the filter choices you should be able to
lock in on almost any repeating waveform.

i don't know if it shows an arrow , i have not seen one, this
Click to expand...
scope may not have that feature as i think i read the 2200 series
tek scopes were meant for production line type work with fewer
user selectable settings and more Auto-magic for "quick use" as
opposed to "thorough use".

Thanks John P,

can't wait to play some more and make the brain connection

thanks again for the help and taking time to respond,
robb
 
robb wrote:
"John Popelish" <jpopelish@rica.net> wrote in message
(snip)
If you trigger the sweep from the same
place in a repeating wave, all the copies that you see will
overlap precisely, and you will have a crisp, stable view.

having read that , i presume that scope quality/value/usefullness
is directly proportional to the variety of user selectable
triggering options/settings ?
Click to expand...
Not proportional, but an otherwise scope with poor sweep
trigger response is almost useless.
(snip)
I'll bet you have yours set
to Auto mode and it is not actually triggering on any part
of the observed waveform.

yes, you are correct, in my case p-p auto

Then you adjust the trigger level,
till it intersects your waveform. I think your scope shows
you a little arrow along the right edge of the screen that
shows you where the level is set if you choose channel 1 or
2 as the trigger signal source. Fiddling around with the
level, and maybe the filter choices you should be able to
lock in on almost any repeating waveform.

i don't know if it shows an arrow , i have not seen one, this
scope may not have that feature as i think i read the 2200 series
tek scopes were meant for production line type work with fewer
user selectable settings and more Auto-magic for "quick use" as
opposed to "thorough use".
(snip)
Click to expand...

Sorry, I was thinking of the newer, digital Teks, that have
all sorts of test and indicator information superimposed
around the edges of the screen.
 
"Phil Allison" <philallison@tpg.com.au> wrote in message
news:5nvo3dFk88n7U1@mid.individual.net...
"robb"
is there a typicle way that data is sent with simpl 4 button
49
MHz remote transmitter ?
just wondering what i should expect to see when pressing a
button.

** Usually, the output of the transmitter is simply turned on
and off with
some type of pattern that identifies which button.

Turn your scope to a slow time base ( like 50mS / division) so
you can see
this pattern.

Usually no direct connection to the device is needed, just make
a loop with
the probe and earth clip, fit it around the unit and find the
best location.
........ Phil

thanks Phil,
Click to expand...

that will be a fun instructive exercise, trying to find the
different signals produced by diff buttons by catching or
comparing diffs on scope.

hope i am not boring you pros too much.

thanks again for helpful reply,
robb
 
"John Popelish" <jpopelish@rica.net> wrote in message
news:9NGdnfGJXr7ZSIHanZ2dnUVZ_r2nnZ2d@comcast.com...
robb wrote:
"John Popelish" <jpopelish@rica.net> wrote in message
(snip)

Sorry, I was thinking of the newer, digital Teks, that have
all sorts of test and indicator information superimposed
around the edges of the screen.

playing with tek 2236 and researching more i probably should have
Click to expand...
gone for a more feature rich series but this suits my hobby
budget and want/need.
thanks again for help,
robb
 
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