Hi

I could either build or buy a signal generator depending on how much pain/price will cost me.

I am after a good sine wave plus the other standard waves generator. I need it to test an inductance capacitance circuit for resonance. up to 1GHz

thx

 

I would buy. Try ebay.

Going up to 1GHz will make it expensive. 100MHz cheaper. Price, as always depends on quality.

Also, you will need measuring equipment to 1GHz - also expensive!

 

in order to produce a precision sine wave at 1Hz to 1MHz. what is the difference between a sine wave generator and a precision one?

I found this http://electronics-diy.com/electronic_schematic.php?id=794 which I can build it up. what do you think about it?

thx

 

Hello,

A precision will probably produce a lower distortion sinewave.
The circuit you show uses a XR2206.
This chip uses the triangle signal for creating the sinewave using a "sinewave shaper".
This will always have some distortion compared to a "true" sinewave generator.

Greetings,
Bertus

 

This will always have some distortion compared to a "true" sinewave generator.

Greetings,
Bertus

Do you recommend a link for a DIY "true" sine wave generator?
How can I build/buy a "true" sine wave generator?

 

Hello,

Take a look at the attached aplication note from TI.

Greetings,
Bertus

 

looking around to buy one. I can not find a unit which states "true" sine wave generator. however from ready, I came across a distortion factor.
what do I look for in order to get a "true" sine wave generator?

thx

 

If you just need to do those resonance tests up to a gig then you're probably better off buying the equipment.

If your goal is to learn about electronics, reactance, resonance, sine wave generation, distortion and topics like that, then you'd learn a lot by making or even buying that XR-2206 circuit and using it to experiment with lower frequency circuits.

But if you're serious, it would be worth it to buy a better quality generator than that
simple board. I'd recommend getting one with a built-in frequency counter, or buying an external frequency counter because it will help make resonance testing so much easier.

I suspect that "true" is being used to describe sine generator that generates a sine from a sine oscillator, as opposed to a generator that first generates a triangle or sawtooth or square wave, or synthesizes a sine from pulse width modulation, then filters out a fundamental sine signal. I'm not sure that "true" really matters so much, as a reasonable sine can be filtered from just about any source.

 

If you really want to get serious about it, then what you need is a network analyzer; most preferably one that has an S-parameter test set either built in, or that comes with it.

Such items aren't particularly cheap, but are the best way to test such things. With the S-parameter test set, you can see transmitted and reflected energy simultaneously.

A (big) step down from that is using a spectrum analyzer with a signal generator; you won't see the reflected energy, but transmitted energy is much better than nothing.
Here's an idea for a cheap 2.4GHz spectrum analyzer:
http://www.circuitcellar.com/library/print/0406/Armitage-189/index.htm
$50 in parts for a PC-based 2.4GHz spectrum analyzer is nothing to laugh at.

Dick Cappels is a member here, and he whipped up this nifty MAX038-based 20MHz sweep/function generator with markers:
http://www.cappels.org/dproj/functsweep/functionswp.html
The MAX038 is tough to find nowadays; it's been out of production since around 2003 after some disaster happened to the factory where they were made.
Futurlec.com apparently still has some in stock, but they're expensive (around $23) and be prepared for them to charge your credit card quickly, and for the parts to take a month or more to arrive.

 

If you really want to get serious about it, then what you need is a network analyzer; most preferably one that has an S-parameter test set either built in, or that comes with it.
...

I ebayed for that and found it pricey.
since I have a very high quality 4 channels scope. is there another machine which my scope would complement rather than spend money for some functionality in the S-parameter Network Analyzer which I have in the scope?

 

What 'scope do you have? And what options are installed in it?

 

If you really want to get serious about it, then what you need is a network analyzer...

I was not able to find that a Network Analyzer produces "true" sine wave.
http://en.wikipedia.org/wiki/Network_analyzer_(electrical)

I need to be able to generate a precision sine wave.

 

What 'scope do you have? And what options are installed in it?

picoscope 4423
http://www.picoauto.com/diagnostic-scopes.html

 

A network analyzer has its' own internal oscillator. They generally produce a very pure sinewave at a very constant level, that's swept across the selected range of frequencies.

Here's another idea for building a vector network analyzer:
http://n2pk.com/

Not a particularly easy build, but you could wind up with up to 500MHz if you do a good job on the oscillator. It's a pretty advanced project, and the components are SMT/SMD.

Your 'scope doesn't have an S-parameter test set - it's just a 4-channel PC-based oscilloscope.

 

what do you think of this one here

 

Those are good units; 300kHz to 3GHz - but they are also ancient.

I see the adapters are missing from the ports. That makes me nervous. Those can be expensive. They are fiddly to connect properly. It's not something you can buy at a local electronics store. If the unit is shipped without the adapters in place, or protective caps on the ports, and they get damaged even slightly, you will have a very expensive repair on your hands.

The interconnecting cables between the analyzer and the S-parameter test set can be "finicky", meaning intermittent. Sometimes all that's necessary is to remove them and clean the connections with pure isopropyl alcohol and a soft nylon brush.

It also makes me nervous that he's selling it "AS-IS", without showing that it works.

While the HP8753B's are actually repairable, you can no longer get replacements for the CRTs. Once the CRT gets too dim to read, you'll either have to figure out how to interface it to an LCD or another type of video output device. It won't be a simple fix. Keep in mind that it was used in a manufacturing environment, daily, for many years.
[eta]
Just found this place sells LCD replacement kits for HP8753B's; prices start at only $1,395
http://www.ntecusa.com/search.cfm?mfrID=240&catID=63
Expensive, but beats having to junk an otherwise good and usable piece of test gear.

[eta]
Don't forget that you'll need proper coax to connect it up with. I prefer to use semi-rigid.

You should also use 6dB attenuators in the coax from both ports. This helps greatly in reducing errors in your readings.

You will also need a calibration kit. They're generally available for both 50 Ohm and 75 Ohm. This isn't something you should scrimp on, as if you don't properly calibrate, you will get poor results. A calibration kit consists of an open, a short, a load, and a through connection.

 

...

A (big) step down from that is using a spectrum analyzer with a signal generator; you won't see the reflected energy, but transmitted energy is much better than nothing.
Here's an idea for a cheap 2.4GHz spectrum analyzer:
http://www.circuitcellar.com/library/print/0406/Armitage-189/index.htm
$50 in parts for a PC-based 2.4GHz spectrum analyzer is nothing to laugh at.
.

Is this able to generate a precision sine wave? would it be software controlled instead of buttons on a box?

 

What do you think of this unit off ebay?

 

Is this able to generate a precision sine wave? would it be software controlled instead of buttons on a box?

Why don't you read the technical documentation supplied?

 

What do you think of this unit off ebay?

If you think you're going to get a perfect sincewave generator for AU$199, I have a bridge for sale that you might be interested in.