I bought this FNIRSI DSO-TC3 primarily to use as a signal generator, although for $40 on Amazon it does a lot of stuff. But I need it to be fairly accurate, and my initial testing suggests it is not as accurate as I need. For example, I think it puts out 215 Hz instead of 220, which is about 2.3% error. I can't find what bit it is, the manual just says it's 1-100khz.

If it's 16 bit, that's a resolution of 1.5 Hz out of 100,000. Am I thinking about this right? What kind of accuracy should I expect from this?

 

FG-300 DDS Function Signal Generator 0.001Hz-200KHz Signal Generator Adjustable Module Sine+Square+Triangle+Sawtooth Waveform
$ 12.85
1. Product Introduction

1.2 Product Features
Using low temperature drift crystal oscillator, high precision DDS frequency synthesis technology, high
frequency stability, resolution up to 0.001HZ, at low frequency accuracy up to 0.001HZ
Can be up to 13 kinds of waveform output, to meet different needs
Color 1.8TFT LCD display, digital keyboard direct input frequency, intuitive and convenient operation.
With timing shutdown, signal light brightness adjustment, screen backlight brightness adjustment.
1.1 Product overview
FG-300 is the multifunctional, high-precision, portable signal generator, which can generate sine wave, square
wave, triangle wave, forward sawtooth wave, reverse sawtooth wave, electrocardiogram, half wave, Loren,
Gaussian, Sinc, Exponential rise, exponential fall, and 7.83HZ Schumann wave and other waveforms. The onboard
spiral antenna can be used as a Schumann wave generator, can be widely used in electronic research and
development, production testing, education and teaching, maintenance, audio testing and other fields.
All setting parameters can be automatically saved, and there is no need to set them in the next startup.

2. Product specifications

Project Parameters
2.1 frequency range: sine wave 0.001Hz-200kHz (where the output amplitude is flat to 100 kHz, the output
amplitude will decrease and the distortion will increase with the further increase of the frequency), and other
waveforms will be 0.001Hz-20kHz (but the upper limit of adjustable frequency is not limited. If the requirements for
distortion and shaking are not high, the use frequency can be further increased).
2.2 waveform types: sine wave, square wave, triangle wave, forward sawtooth wave, reverse sawtooth wave,
electrocardiogram, half wave, Loren, Gauss, Singh, exponential rise, exponential fall, and 7.83HZ Schumann wave
2.3 output amplitude: 2. 5V
2.4 output impedance: 330 ohms
2.5 display: 1.8 inch TFT display
2.6 supply voltage: USB-TYPE C
2.7 dimensions: length 125MM width 95MM high 18mm

 

I have not seen a signal generator with dial markings good enough tor a receiver alignment. THAT is why they make accurate frequency counters.

 

I returned the FNRISI and got this Owon

https://a.co/d/8eRyQDD

this guy loves it.

 

tsk tsk... no foldout legs ;-D

 

The temperature controlled crystal oscillators 32.768kHz TCXO good enough specs.
The DS3231 which is fairly accurate as a digital time clock. The analog output of a TCXO some very low ppm might be used
to check low frequency equipment for frequency accuracy. The 3rd harmonic 10.923 kHz and so on.

Fnirsi should have used a tuning fork crystal. they are not that expensive. The digital design is not what will be remembered.

 

I returned the FNRISI and got this Owon
https://a.co/d/8eRyQDD
this guy loves it.

Ultimately I returned the Owon and got a Siglent SDG1022x+ from Saelig. I've been using it to do bode plots with my SDS804xhd.

 

Ultimately I returned the Owon and got a Siglent SDG1000x+ from Saelig. I've been using it to do bode plots with my SDS804xhd.

Been a good journey too.
https://www.eevblog.com/forum/testgear/bode-plot-on-siglent-sd804x-hd/