#43: Analog Oscilloscope Basics: Making a Frequency Measurement 

I hope you like the rest of my videos just as much!

How is the 465B working out for you and is it not too difficult to understand/learn?there is one for sale in my area and I might buy it. I could use it to trouble shoot some stereos that I have.Cheers/Rob

+Rob Hernandez The 465B has been working out just fine. Still works good and haven't had any problems with it. Not too difficult to work with I don't think. Everything has been pretty straight forward and they're built like tanks so you can't really go wrong with one. I would recommend it in a heartbeat.

Thank you very much Redemptus I think I am going to go for it. I have heard that the Tektronix brand is a good one. And I believe this model comes with a DMM built in? What can you use the DMM for?

Rob Hernandez The DM44 is an option for the scope so you'll find that not all of them have it. It allows you to measure DC voltage, resistance, temperature (with the temp probe, mine didn't come with the probe and it appears that Option 1 specifically excludes the probe to save on price,) as well as differential delay time (the time between any two points on the oscilloscope trace.) Honestly, I haven't used mine as it didn't have any probes though I think it can use standard 4mm banana plugs but don't quote me on that. Update: Couldn't leave well enough alone so I got some probes and sure enough it will take the standard unshrouded banana plugs. I'd have to read up on how to measure the delay between two points on the trace though as I'm not sure how that works yet. Guess I have to schedule some experimentation time soon. :)

Well that is good to know, I think one that is for sale in my area does not come with the DMM. I am sure that you eventually will figure it out, Good luck. Ah and good to know that you can use the banana plugs. Cheers

Most transmitters and receivers use a superheterodyne architecture. Thus, the operating frequency is controlled by a Local Oscillator (LO). It is most common to attach the Frequency Counter to the LO output, and then apply a frequency offset in the counter to correct for the IF frequency.

@@w2aew Much appreciated the comment.

There are a lot - some on the vertical controls, some on the triggering controls, and a lot on just basic usage...

I've got a couple of videos on using the delayed sweep, and the triggering on that: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-J-7MycqHPOs.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vvqVTD-VEow.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0enuruGWYk8.html

That's not how an oscilloscope works. The scope displays what is connected to the vertical channel input(s). So, in your case, it is displaying a flat line that represents the 9Vdc that you connected to it. Instead, connect your 1kHz signal to channel 1 and change the trigger source to channel 1, and you'll see your signal generator's output.

Sure, if you have a "known" frequency source, you can use that to check the horizontal calibration of your scope.

Are you sure about that Tek scope number? I don't recognize that as an old Tek analog scope. I know there was a 5440 scope (analog scope with 3 plug-in slots). The digital scope will usually have an RMS measurement as part of their automatic measurement system. An analog scope can not show you the RMS value as a trace directly.

@@w2aew The Tek 5440 is aka (5403/D40). My digital scope with state the RMS figure but won't plot it. Does Tek's new digital scope plot the calculated RMS?

@@rpbale Newer scopes can plot measurement trends

Thank you, and He already has!

1 divided by 12.5us = 80,000, or 80kHz.

I have videos on these topics. They show the features on a Tektronix scope, but the operation would likely be similar on your scope. The Delay Time, A and B Time/Div settings all refer to a dual, delaying timebase. This is how you "zoom" on a portion of a waveform with an analog scope. Here are 4 videos on the topic: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-54roz8IUoVI.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-J-7MycqHPOs.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0enuruGWYk8.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vvqVTD-VEow.html The coupling controls to listed (AC, HF-REJ, TV-V, TV-H) and the Source controls (ALT, CH1, CH2, Line, EXT) all refer to the Trigger operation. I have several videos on these. I don't cover TV-V or TV-H though. These two settings allow you to trigger on vertical sync or horizontal sync signal on TV composite video signal. If you never work on a TV, you'll never need these trigger settings. AC coupling means that the signal going to the trigger circuit will be AC coupled. HF-REJ will filter away any high frequency noise on the trigger signal. Here are some videos on Trigger controls: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-OFGm-Pel4Hg.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BKjJK1rsZmM.html

do 30 year old Digital Scopes Exist ? i wouldn't have thought so if they do , then it must have been right at the beginning of their introduction I have 2 C.R.O.'s 1 is from the the early 60's i think the brand was BCD and the other is a KIKUSUI CRO from the 80's, 84 i think then i have a Rigol Digital Scope as well DS2000A Series i do prefer my old CRO's though

Make sure your trigger setting it set to NORMAL, not AUTO. 10Hz is difficult on an analog scope due to the slow sweep speed needed.

Thanks for the reply. Yes, I tried those setting, but could not get a stable waveform. Is the sweep setting a parameter that I could check in a specs of a scope. i.e if I am getting a dig scope, is there some min value I should check in the spec to make sure the sweep speed is low enough to get a stable 10Hz waveform display?

Was it not stable, or just not a continuous picture. WIth an analog scope running at such a slow sweep speed, it is impossible to get a continuous waveform unless the scope has a persistence type display. Just about any digital scope will show you a good waveform.

It was definitely not continuos (so the rise and fall of the signal could not be seen) but the levels (H and L) were also flickering on the screen (not sure if this has anything to do with my HOLD OFF setting)?

Probably not. For a 10Hz signal, the period is 100ms, which means that the horizontal timebase setting needs to be set to 10ms/div or higher, in order to see one cycle. Slower settings (like 20ms/div) will show you more cycles. Trigger holdoff should be set to min. Trigger mode set to Normal (not Auto). Trigger coupling to DC, and level set midway between the high and low values. It WILL still flicker because the sweep speed is slow - totally normal, and as good as you can get, but you should be able to see both high and low levels on a single sweep. The rise and fall times might be too fast to "see" at this low sweep speed, so it will just look like horizontal line segments.

Generally you'd be better off with a function generator. It would be difficult to observe distortion in an amplifier if you used a pulse generator.

@@w2aew ty i really apperciate it i been looking for a answer for a month thanks alot...

LOL.... What EXACTLY is it that you want to learn my friend ? Perhaps i can put you on the right path. but first i need to know where you're coming from Do you just like Oscilloscopes or do you actually want to learn Electrical and Electronics Engineering or, Do you just prefer to be an Electronics Hobbyist or... did you have something else in mind Because when you say something like.... I WANT TO LEARN EVERYTHING you first need to know what he knows before you can know that you want learn everything then.... Even once you know what he knows i'ts a long hard road to learning everything he knows i mean.. you can't seriously expect him to put around 5 years of effort into you to teach him everything so... to make the decision easier and more structures WHAT EXACTLY ARE YOU EXCITED ABOUT and i'll see if i can help you

An audio waveform, just a music, doesn't contain just one frequency - it contains an entire range of frequencies. In order to determine the frequency content you'd need a spectrum analyzer or use the FFT function of a modern digital oscilloscope.

This is a custom IC that was designed and fabricated at Tektronix, there is no commercial replacement for it. The design of the chip is quite simple, and might be able to be replicated discretely, or it's function could be duplicated with a modern quad op amp (provided the application doesn't also need to control the BIAS node (pin 12). Here is the basic design information for this chip: w140.com/tekwiki/images/0/0d/Tek_m053.pdf Looks like someone on the TekScope group did make a descrete replacement: groups.io/g/TekScopes/album?id=28989

A scope isn't the best tool for measuring RF frequency - typically not very accurate, only good to a few percent. However, it can be done. Do NOT connect the transmitter directly to the scope! The scope input's 50 ohm termination (if it has one) is typically rated to a few hundred milliwatts at best. If you want to couple the transmitted signal to the scope, you're better off using an RF Sampler/Tap, or even an antenna in the proximity of the transmitted signal.

thanks mate, yeah kind of knew i couldn't connect directly but was unsure how, all my scopes inputs are 1Mohm 20 picofarrad . what about looking at a 240v AC sine wave ? ( or rather 12v for safety) how would i so that ? cheers :)

You're probably better off going with a spectrum analzyer. signals directly from radio are not like a raw sine wave First of all they will have modulation and that right there is opening a can of worms so to speak simple answer... Get a spectrum analzyer or an MSO

Sounds like you have a 10x magnifier turned on on the horizontal. My earlier comments about 1x/10x was referring to probes, since many scopes don't have the Horizontal zoom. Turn the 10x zoom off, or calculate using 0.2ms/div divided by 10.

12.5us is equal to 0.0000125 seconds. 1/0.0000125 equals 80,000Hz, or 80kHz.

I see now, i was being daft and mixing hz with khz.. Thanks for helping with my 'new' old scope😁

WIth a decent 10x probe, sure you can.

@@w2aew i have a tenma 72-3055...i do not know how to use it..its my first scope..i want to use to work on vintage arcade games pcbs.

@@markherring3513 You may want to review many of the videos I have in this playlist to learn how to use your scope. ru-vid.com/group/PL746BF38BC2E068E0

You would have to have a log waveform that corresponds to the frequency sweep as use this as the X input.

yes you set your function generator/audio generator to LOG sweep. The Oscope has 8 boxes divisions. How do you set up the Oscope so each box division is a Decade so its 1,10,100,1000,10000 etc. Does the function generators sweep time setting have to be the SAME sweet time setting as the Oscope time base setting?

@@waynegram8907 Most oscilloscopes have 10 divisions horizontally. If you can get a log sweep from your function generator, then set your scope's horizontal sweep time to 1/10th of the generator's sweep time (so that the total sweep time is the same). Remember that the scope's sweep time is time/division, and with 10 divisions horizontally, you'll have the same total sweep time.

thanks for the help, can you please give an example of the generators sweep time setting the setting the Oscopes timebase sweep time to 1/10th? what formula calculation did you do to get the sweep times to work together for log sweeps? I enter in my calculate the generators sweep time and then "divide it by 10" to get that Oscopes timebase sweep time?

@@waynegram8907 If you set your function generator sweep time to 100ms, then set your scope to 10ms/div.

No - the 1x or 10x probes only affect the vertical scaling, not the horizontal. You *should* be using 10x for anything over several kHz though...