Function Generator purchase advice

[ampedtech]

Hope all are well today

Any words, good or bad, about this generator, would be greatly appreciated before I whip out the card.


Perhaps you would care to tout a different generator for quality or more or better features.


I am a hobbyist with no specific project in mind.

Wavetek Function Generator (60 MHZ) FY 6900​

Wavetek Function Generator (60 MHZ) FY 6900

Wavetek 60MHz Function Generator Digital DDS Function Signal/Arbitrary Waveform Generator Pulse Signal Source 250MSa/s Frequency Meter VCO Burst AM/PM/FM/ASK/FSK/PSK Modulation Source Generator Description: The instrument uses 14-bit high-speed D/A converter chip, 250MSa/s sample rate, 14bits...

www.wavetek.com

 

[JimB]

Speaking from a position of no direct experience of that particular generator...
Wavetek have been in the function generator business for a long time, and have usually made reasonable equipment.

However, looking on the interwebs I found an identical looking generator, the FeelTech FY6900, which has been reported by a couple of people as having problems.

Others seem to have no problem with it.

I am guessing that it is a design which has been badge engineered by various companies.

As a general purpose signal source it will probably be fine
However, as a hobbyist, if your scope of interest includes radio, you will probably find that the output level and direct signal leakage from the case make it unsuitable for meaningful testing of receivers.

JimB

 

[danadak]

Cheaper -

Function Generator 60MHz DDS for sale | eBay

Get the best deals for Function Generator 60MHz DDS at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!

www.ebay.com

Regards, Dana.

 

[ronsimpson]

I have several. All I know of, do not make a square wave at maximum frequency. At 60mhz it looks like a sine wave. Even on the really costly generators.
Here is a picture of what I have for the about $160usd. It stays on 24/7 for a year without trouble. I also have a $8000 one that I don't use.

If you really need a square wave it has "TTL" outputs on the back side.

It appears to me that one company makes the PCB with parts and several different companies put their names on it.

I got the generator because I needed a pulse every 10 minutes that slowly shifted to every 1 minute over two days. These things are really programmable.

 

[ampedtech]

Cheaper -




Regards, Dana.

Wavetek have been in the function generator business for a long time, and have usually made reasonable equipment.

However, looking on the interwebs I found an identical looking generator, the FeelTech FY6900, which has been reported by a couple of people as having problems.


Others seem to have no problem with it.
..
I am guessing that it is a design which has been badge engineered by various companies.

As a general purpose signal source it will probably be fine
However, as a hobbyist, if your scope of interest includes radio, you will probably find that the output level and direct signal leakage from the case make it unsuitable for meaningful testing of receivers.

JimB

Dana, you think like I do, cheaper, but like JimB I believed that Wavetek has been in the bis a long time. I thought: maybe a better product. Imagine my dismay when I went to their site and selected the "Function Generators" tab (that's with an S) and only one product poped up. Then they tormented me with this:


"Showing 1-1 of 1 results"
"Compare Function Generators specifications and find the right Wavetek Generator for your needs. Browse through a wide selection of function and signal generators."

And , you both enlighten me that it is probably a Your Name Here kinda product.

I will call them on Monday.


JimB, kind Sir, perhaps you could elaborate on the case leakage and the output level unsuitability for radio.

What specification or feature makes a generator good with radio?

I will offer a guess here, not enough power on the output and a foil hat for the Wavetec won't shield it properly.

 

[danadak]

Drive 50 ohms with low jitter important spec.

Harmonic suppression, especially when doing sines.

The wavetek probably a china knock off. If you can see a pic of the board inside and
compare with China clone I would lay odds they are same.

Regards, Dana.

 

[JimB]

perhaps you could elaborate on the case leakage and the output level unsuitability for radio.

When testing a radio receiver it is often necessary to inject signals of less that 1uV into the antenna connector of the radio.

A signal generator will have an oscillator of some kind, and a power supply.
The RF output from the oscillator will pass through an attenuator of some kind before it goes to the output connector where we connect the screened (coaxial) cable which connects to the receiver antenna connector.

If the oscillator is not installed in a well screened box,
If the wiring to the oscillator from the power supply is not well well filtered to prevent the oscillator signal escaping from the screened box,
If the attenuator assembly is not well screened,
If the coax cable from the oscillator box to the attenuator box, and from the attenuator box to the output connector is not well screened.
Then the signal generator will radiate a signal, like a little transmitter, an we will not be able to measure the sensitivity of the radio receiver with any accuracy.
This is what I mean by "case leakage", signal just leaking out of the signal generator case.

To adjust the output level of the signal generator, we must have a well screened attenuator unit, otherwise we will not be able to make signals as small as 1uV or less.

But if you are not working on sensitive radio equipment, these features are not so important.

Look here:

Dds signal generator module

I started looking for a design for a hombrew signal generator, and discovered these: http://www.ebay.co.uk/itm/New-0-40MHz-TAD9850-DDS-Signal-Generator-Module-Test-Equipment-/400503255267?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item5d3fdab0e3 (there is a different design board on...

www.electro-tech-online.com

and here:

https://www.electro-tech-online.com/threads/dds-signal-generator-revisited.150114/

...to see some of my adventures in making a usable signal generator.

JimB

 

[ampedtech]

Ok, kids only fair to tell you all I bought one. Before I tell which one and how much I must thank all that chimed in.

JimB thanks for the extra poop on output an leakage.

Dana, JimB and Ronsimpson thanks for pointing out that there is one product and many names.

So.............I think I found the cheapest, Dana are you proud?

2.4 inch Signal Generator;FY6900-60M Multi-Functional Digital Signal Generator Counter Frequency Meter (US Plug 110V): Amazon.com: Industrial & Scientific

2.4 inch Signal Generator;FY6900-60M Multi-Functional Digital Signal Generator Counter Frequency Meter (US Plug 110V): Amazon.com: Industrial & Scientific

www.amazon.com

I paid $42.55 b4 tax and after a 10% coupon

 

[MacIntoshCZ]

I own FY6900. It survives many of my experiments. Which could be interpeted as i am getting better or its actually idiot proof.
Its nothing fancy. It actually suffer if its in noisy environment - Outputs stays on so be sure you have cap in series when driving mosfets...
For that price... I am ok with that. Better than nothing

 

[ronsimpson]

Better than nothing

Good words. Most of us will have nothing if $3000.00 is the only option.

 

[MacIntoshCZ]

Good words. Most of us will have nothing if $3000.00 is the only option.

My month salary is 1120USD after taxes, so maybe after i spend 3 months under bridge i could buy better equipment =).
I use only pulse generator as input for mosfet drivers. I have never used sweep function etc. So It depends on which purpose you want it.

 

[Nigel Goodwin]

I've got a similar Chinese function generator, it does what you need, I see no reason for anything more expensive?.

 

[MacIntoshCZ]

I've got a similar Chinese function generator, it does what you need, I see no reason for anything more expensive?.

having chinese equipment could be considered as being chinese spy nowadays in some countries across world.
lol.
its a joke

 

[Nigel Goodwin]

having chinese equipment could be considered as being chinese spy nowadays in some countries across world.
lol.
its a joke

They wouldn't learn much from me

 

[ronsimpson]

Recently I purchased two pieces of test gear directly from Chine. (Post #4 and a VNA)
Both came from a "demo board" that a chip maker published. All of the little DC-DC power supplies I see on Alie are directly copied from an example in the data sheet.
When we need to make a new "thing" often we need a new IC that does not exist. That costs big money. To keep the R&D budget down we can partner with the chip maker and they get to offer the chip on the market after 6 months or a year. The silicon company will make a working PCB to show how to use the new IC. This gets copied and appears in China. In some cases it is clear that China does not know how it works, but in other cases cleaver improvements are added.

With the current lack of science and math in the US, soon China will be making the custom ICs and we will be farming rice.

IMO this is how the world turns. RonSimpson