24
votes
Accepted
Hobby function generators
I actually own a FY3200S signal generator. When I bought it, I was already aware of the questionable quality of the switching power supply inside it, and the reported high earth leakage currents. For ...
- 2,606
21
votes
Accepted
Function generator in the nano or micro volt range
At relatively low frequencies you can simply divide down the voltage from an ordinary function generator. Very accurate, cheap and fairly low output impedance is easy.
For example a 100K resistor ...
19
votes
Accepted
How do digital function generators generate precise frequencies?
That sort of generator uses DDS, or Direct Digital Synthesis
It keeps track of the phase of the required output in a register, and outputs the cosine of the phase.
To use nice round numbers, let's say ...
- 171k
16
votes
Why can we hear the full range of square waves from 1 Hz-20 kHz, but not sine waves of the same frequencies?
Most people can't hear sinewaves below about 20 Hz. The fact that you couldn't hear them until they got to 100 Hz is probably due to poor low-frequency response in your amplifier/speaker.
When you ...
- 177k
13
votes
Do 50 Ω signal generators have a series resistor or not?
More precisely, they have whatever impedance makes up the difference. Or, they should, anyway.
For example, my old Wavetek 193 has a discrete (complementary emitter follower, more or less) output ...
- 43.7k
11
votes
Accepted
Why do I get 0 volt output when I have a voltage divider with a square wave input?
If you're using a 10x oscilloscope probe on the output of the function generator, there is a 9 Megohm resistor in series with the probe. When the floating end of the resistor divider is grounded, this ...
- 10.5k
10
votes
What is a best way to get a 25% duty cycle square wave (5 V, 1 MHz) on a board?
If you're considering this: -
Combine op amps to generator the square wave
Then, the LTC6992 from here appears to do what you want.
I am trying to get two off-phase 25% duty cycle square waves(...
- 467k
10
votes
Accepted
Do 50 Ω signal generators have a series resistor or not?
do they have this series resistor R1 and if yes, what is the
motivation behind it
Signal generators that are specified as having an output impedance of 50 Ω have a 50 Ω output resistor and, when ...
- 467k
9
votes
Do 50 Ω signal generators have a series resistor or not?
They should act as if they do.
An ideal 50Ω output impedance output should produce the requested output into a 50Ω load. A good test of how ideal it is is whether it produces double the voltage into ...
- 171k
8
votes
What is causing this Op-Amp Distortion
Since you're new to electronics I simplify here a little bit:
OpAmps don't have the current drive capability to drive speakers directly. Speakers usually have a impedance in the low ohms. 8 Ohm is ...
- 5,157
8
votes
Hobby function generators
As low-tech as it sounds, I recommend using two lithium 9V blocks. It's simple, cheap, portable, has no mains nor buck converter artifacts. And it can sit on your shelf for years and just works when ...
- 14.4k
7
votes
Square wave to sawtooth wave using two BJT
You should just plug this circuit topology into circuit simulator and start experimenting to figure out on your own how these work. This way you will learn the most.
These circuits use one transistor ...
- 57.6k
7
votes
Accepted
How to generate a complex sinusoidal signal on a function generator?
Complex signals don't exist in the real world. They are a mathematical tool. However, complex signals can be represented in quadrature--using two separate signals, one representing the real part, ...
7
votes
Accepted
Modulating a high-frequency signal to get rid of an undesired low-frequency component
For such measurements done with a sampling oscilloscope, the time base of the scope and of the function generator must be synchronized to a common reference.
In a lab where you deal with precise ...
6
votes
What is causing this Op-Amp Distortion
There are several things wrong here. You say you want to drive a 8 Ω speaker with 15 W. That means you need sqrt((15 W)(8 Ω)) = 11 V. Note that this is RMS. For a sine wave, that means ...
- 314k
6
votes
Why do TTL pulse generators generate an asymmetrical square wave (unlike CMOS)?
Two reasons. First, a TTL input is actually an output. It sources a current that must be shunted to ground to be seen as a logic 0. This current affects the charging rate of the timing capacitor, ...
- 22k
6
votes
Why do TTL pulse generators generate an asymmetrical square wave (unlike CMOS)?
CMOS Schmitt triggers have the two threshold voltages at \$\frac 1 3 V_{DD}\$ and \$\frac 2 3 V_{DD}\$. Furthemore \$V_{OH}=V_{DD}\$ and \$V_{OL}=0\$.
Since this is symmetric with respect to \$V_{DD}/...
- 5,367
6
votes
Accepted
Locked-Sync Sine Generator Covers Three Decades with Low Distortion
1) I don't see why not. The article has the manufacturer's name on it, much more reputable than 'some guy off the internet'. Without actually building or simulating it, or doing calculations around R2/...
- 171k
6
votes
Function generator in the nano or micro volt range
You can use any generator and simple voltage divider made using two resistors with values what are needed to provide proper divide ratio and output resistance.
- 1,588
6
votes
How do digital function generators generate precise frequencies?
You can teardown your cheap function generator, I am certain you will find a DDS chip or a FPGA doing the same. However it is possible to increment/decrement frequency in range of milihertz but the ...
- 24.2k
6
votes
Do 50 Ω signal generators have a series resistor or not?
They do.
Just measure any standard signal generator into no load and into 50 ohm load, and you will see the amplitude drop to half.
They compensate for that by having a menu to select if the amplitude ...
- 165k
6
votes
Using a function generator as a clock source to drive several ICs (CD4000 CMOS series & 74 TTL)
I tried to use it but I have a hard time getting the circuit to work, firstly when adjusting the amplitude to be 5V peak (+5-5) square wave
It should be 0V..5V, not -5V..+5V!
the ICs don’t seem to ...
6
votes
50 ohm vs HiZ setting on function generator?
The setting simply selects what load impedance you have so that the display reads the voltage you get at the load.
For example if the unloaded output is 2Vpp, it will be 1Vpp when you connect a 50 ohm ...
- 165k
5
votes
Accepted
What switch would replace a series of 6 pins linked by jumpers?
It's a bit hard to answer without a schematic, but a rotary switch is a typical solution. You can get them in many different configurations. For example, a four position double pole switch as shown ...
- 7,975
5
votes
Why can we hear the full range of square waves from 1 Hz-20 kHz, but not sine waves of the same frequencies?
The basic difference is that a sine wave is only a single frequency, but a square wave is actually made up of the fundamental frequency plus odd harmonics. So for example a 50Hz square wave isn't just ...
- 56.8k
5
votes
Function generator in the nano or micro volt range
I think that you are simply looking for good old attenuators.
They are easily available: https://uk.rs-online.com/web/c/connectors/rf-coaxial-connectors/rf-attenuators/
You can connect them together ...
- 9,066
5
votes
Accepted
Do function generators produce AC signals in the sense we know?
I bought the ultra-cheap function generator last year. It is based on an XR2206 IC clone. It is barely usable. The sine and triangle waves have DC superimposed, you need to add your own cap to remove ...
- 16.6k
5
votes
What is a best way to get a 25% duty cycle square wave (5 V, 1 MHz) on a board?
This was not my own idea. I got it from @Swedgin's comment.
simulate this circuit – Schematic created using CircuitLab
Also, Thanks @StainlessSteelRat for suggesting an improvement.
Output ...
- 3,339
5
votes
Oscilloscope voltage not matching function generator
Most function generators will display the voltage output value that would be seen when running into a load terminator of the same impedance as the function generator. You are running the output (...
- 467k
5
votes
Accepted
High voltage amplification of a waveform generator output
Ultrasonics are driven by peculiar means. If you also need to receive (I assume you don't) you also need to worry about the T/R switches.
There are two kind of transducer: resonant and wide band. A ...
- 8,556
Only top scored, non community-wiki answers of a minimum length are eligible