An application that allows you to transmit sound of different frequencies through several channels is indispensable when setting up professional music systems.

Audio frequency generator - the name of the program speaks for itself. There is another name for the application "Sound Generator". The system allows you to transmit sound with the additional ability to customize signal characteristics. An important advantage of the application is the ability to transmit multi-channel sound. When the generator is turned on, nine separate panels light up with the function of possible frequency adjustment for each channel. Their location can be changed or fixed in the desktop area.

Application Features

The audio application is compatible with 24-bit and 32-bit cards, and the sampling rate must be 384 kHz. It is possible to transmit noise and harmonic sinusoidal signals. Changing sound phases is easy by mechanically switching the system. Often these functions are used when using professional equipment.
The audio frequency generator is a highly focused application. This is due to the following functions:

• The frequency range is not limited, depending on the technical capabilities of the sound system;
• the generator provides for the operation of two or more oscillators with the function of simultaneously changing the characteristics of sound transmission;
• modes for reproducing Brownian, white and pink noise are provided, as well as transmitting amplitude modulation and swinging frequency of electrical oscillations;
• the audio application has the lowest percentage of distortion;
• The processed sound can be saved to your computer.

The developers equipped new variations of the program with templates with specified sound characteristics. It is enough to find a ready-made preset on the desktop and launch it by double-clicking the left key. The sound generator is easy to use. The only downside is that the free version of the program is a trial version, and its sound lasts about twenty seconds. To fully operate the application you need to purchase a license.

is an application for Android smartphones and tablets that generates an audio tone of a user-specified frequency using the device's speaker. A simple interface with a minimum of details and the ability to fine-tune make it useful for both domestic needs and professional work with sound.
The generator produces sound at a specified frequency as a pure tone (with a sine waveform).

It works in monophonic mode. The active frequency in Hz is indicated at the top of the screen. Below it is a scroll bar for quickly moving through the entire available range. Fine tuning is carried out using the frequency increase and decrease buttons. The values ​​​​on them are almost universal: hundreds and tens of hertz are used for quick navigation, and their tenths are used for fine tuning. The latter is especially important when working with low frequencies. At the bottom of the screen there is a button to turn the sound on and off. The application does not provide software volume control, so before using the generator it is worth adjusting the volume of the device itself so as not to injure the hearing of yourself or others.

is absolutely free, but during its operation it shows the user an advertising banner at the bottom of the window. It does not support the Russian language, but it is not required - the digital symbols are understandable in any language, and there is no other data or settings in the application. The generator is suitable for all devices with Android OS older than 4.0. A functional, hardware-undemanding interface and the small size occupied by the application in the memory of a smartphone or tablet allow you to work with it even using budget mobile devices.

SoundCard Oszilloscope - a program that turns your computer into a two-channel oscilloscope, a two-channel low-frequency generator and a spectrum analyzer

Good afternoon, dear radio amateurs!
Every radio amateur knows that to create more or less complex amateur radio devices, you need to have at your disposal not only a multimeter. Today in our stores you can buy almost any device, but - there is one “but” - the cost of a decent quality device is no less than several tens of thousands of our rubles, and it is no secret that for most Russians this is a significant amount of money, and therefore these devices are not available at all, or a radio amateur buys devices that have been in use for a long time.
Today on the site , we will try to equip the radio amateur laboratory with free virtual instruments -digital two-channel oscilloscope, two-channel audio frequency generator, spectrum analyzer. The only drawback of these devices is that they all operate only in the frequency band from 1 Hz to 20,000 Hz. The site has already given a description of a similar amateur radio program:“ “ – a program that turns your home computer into an oscilloscope.
Today I want to bring to your attention another program - “SoundCard Oszilloscope“. I was attracted to this program by its good characteristics, thoughtful design, ease of learning and working in it. This program is in English, there is no Russian translation. But I don't consider this a disadvantage. Firstly, it’s very easy to figure out how to work in the program, you will see it yourself, and secondly, someday you will acquire good devices (and they have all the symbols in English, although they themselves are Chinese) and you will immediately and easily get used to them.

The program was developed by C. Zeitnitz and is free, but only for private use. A license for the program costs about 1,500 rubles, and there is also a so-called “private license” - costing about 400 rubles, but this is more of a donation to the author for further improvement of the program. Naturally, we will use the free version of the program, which differs only in that when you launch it, a window appears each time asking you to buy a license.

Download the program (latest version as of December 2012):

(28.1 MiB, 52,981 hits)

First, let's understand the “concepts”:
Oscilloscope– a device designed for research, observation, measurement of amplitude and time intervals.
Oscilloscopes are classified:
♦ by purpose and method of displaying information:
– oscilloscopes with periodic scanning for observing signals on the screen (in the West they are called oscilloscop)
– oscilloscopes with continuous sweep for recording the signal curve on photographic tape (in the West they are called oscillograph)
♦ by the method of processing the input signal:
– analog
– digital

The program runs in an environment no lower than W2000 and includes:
- two-channel oscilloscope with a transmission frequency (depending on the sound card) of at least 20 to 20,000 Hz;
– two-channel signal generator (with a similar generated frequency);
- spectrum analyzer
– and it is also possible to record an audio signal for later study

Each of these programs has additional features that we will look at as we explore them.

We'll start with the signal generator:

The signal generator, as I already said, is two-channel – Channel 1 and Channel 2.
Let's consider the purpose of its main switches and windows:
1 – buttons for turning on generators;
2 – Output waveform setting window:
blue– sinusoidal
triangle- triangular
square- rectangular
sawtooth- sawtooth
white noise- White noise
3 – output signal amplitude regulators (maximum – 1 volt);
4 – Frequency setting controls (the desired frequency can be set manually in the windows under the controls). Although the maximum frequency on the regulators is 10 kHz, you can enter any allowed frequency in the lower windows (depending on the sound card);
5 – windows for setting the frequency manually;
6 – turning on the “Sweep – generator” mode. In this mode, the output frequency of the generator periodically changes from the minimum value set in the “5” boxes to the maximum value set in the “Fend” boxes during the time set in the “Time” boxes. This mode can be enabled either for any one channel or for two channels at once;
7 – windows for setting the final frequency and time of Sweep mode;
8 – software connection of the generator channel output to the first or second input channel of the oscilloscope;
9 - setting the phase difference between the signals from the first and second channels of the generator.
10 -at setting the duty cycle of the signal (valid only for a rectangular signal).

Now let's look at the oscilloscope itself:

1 – Amplitude - adjusting the sensitivity of the vertical deflection channel
2 – Sync– allows (by checking or unchecking) separate or simultaneous adjustment of two channels according to signal amplitude
3, 4 – allows you to separate signals along the height of the screen for their individual observation
5 – setting the sweep time (from 1 millisecond to 10 seconds, with 1000 milliseconds in 1 second)
6 – start/stop operation of the oscilloscope. When stopped, the current state of the signals is saved on the screen, and a Save button appears ( 16 ) allows you to save the current state on your computer in the form of 3 files (text data of the signal under study, a black and white image and a color image of the picture from the oscilloscope screen at the time of stop)
7 – Trigger– a software device that delays the start of a sweep until certain conditions are met and serves to obtain a stable image on the oscilloscope screen. There are 4 modes:
– on/off. When the trigger is turned off, the image on the screen will look “running” or even “smeared”.
– auto mode. The program itself selects the mode (normal or single).
– normal mode. In this mode, a continuous sweep of the signal under study is carried out.
– single player mode. In this mode, a one-time sweep of the signal is carried out (with a time interval set by the Time regulator).
8 – active channel selection
9 – Edge– signal trigger type:
- rising– along the front of the signal under study
– falling– according to the decline of the signal under study
10 – Auto Set– automatic setting of sweep time, sensitivity of the vertical deviation channel Amplitude, and also the image is driven to the center of the screen.
11 -Channel Mode– determines how signals will be displayed on the oscilloscope screen:
– single– separate output of two signals to the screen
- CH1 + CH2– output the sum of two signals
– CH1 – CH2– output the difference between two signals
– CH1 * CH2– output of the product of two signals
12 and 13 – selection of display of channels on the screen (or any of the two, or two at once, the value is displayed next to Amplitude)
14 – channel 1 waveform output
15 – channel 2 waveform output
16 – already passed - recording a signal to a computer in the oscilloscope stop mode
17 – time scale (we have a regulator Time is set to 10 milliseconds, so the scale is displayed from 0 to 10 milliseconds)
18 – Status– shows the current state of the trigger and also allows you to display the following data:
- HZ and Volts– displaying the current voltage frequency of the signal being studied
– cursor– inclusion of vertical and horizontal cursors for measuring the parameters of the signal under study
– log to fille– second-by-second recording of the parameters of the signal under study.

Taking measurements on an oscilloscope

First, let's set up the signal generator:

1. Turn on channel 1 and channel 2 (green triangles light up)
2. Set the output signals - sinusoidal and rectangular
3. Set the amplitude of the output signals to 0.5 (the generator generates signals with a maximum amplitude of 1 volt, and 0.5 will mean a signal amplitude equal to 0.5 volts)
4. Set the frequencies to 50 Hertz
5. Switch to oscilloscope mode

Measuring signal amplitude:

1. The button below the inscription Measure select the mode HZ and Volts, put a tick next to the inscriptions Frequency and Voltage. At the same time, the current frequencies for each of the two signals (almost 50 hertz), the amplitude of the complete signal appear on top Vp-p and effective signal voltage Veff.
2. The button below the inscription Measure select the mode Cursors and put a tick next to the inscription Voltage. In this case, we have two horizontal lines, and at the bottom there are inscriptions showing the amplitude of the positive and negative components of the signal ( A), as well as the overall signal amplitude range ( dA).
3. We set the horizontal lines in the position we need relative to the signal, on the screen we will receive data on their amplitude:

Measuring time intervals:

We perform the same operations as for measuring the amplitude of signals, with the exception of - in the mode Cursors put a tick next to the inscription Time. As a result, instead of horizontal ones, we will get two vertical lines, and at the bottom the time interval between the two vertical lines and the current frequency of the signal in this time interval will be displayed:

Determining signal frequency and amplitude

In our case, there is no need to specifically calculate the frequency and amplitude of the signal - everything is displayed on the oscilloscope screen. But if you have to use an analog oscilloscope for the first time in your life and you don’t know how to determine the frequency and amplitude of a signal, we will consider this issue for educational purposes.

We leave the generator settings as they were, with the exception of setting the signal amplitude to 1.0, and setting the oscilloscope settings as in the picture:

We set the signal amplitude control to 100 millivolts, the sweep time control to 50 milliseconds, and we get a picture on the screen like above.

The principle of determining the signal amplitude:
Regulator Amplitude we are in a position 100 millivolts, which means that the cost of dividing the grid vertically on the oscilloscope screen is 100 millivolts. We count the number of divisions from the bottom of the signal to the top (we get 10 divisions) and multiply by the price of one division - 10*100= 1000 millivolts= 1 volt, which means that the signal amplitude from the top to the bottom is 1 volt. In exactly the same way, you can measure the signal amplitude in any part of the oscillogram.

Determination of signal timing characteristics:
Regulator Time we are in a position 50 milliseconds. The number of horizontal divisions of the oscilloscope scale is 10 (in this case, we have 10 divisions on the screen), divide 50 by 10 and get 5, this means that the cost of one division will be equal to 5 milliseconds. We select the section of the signal oscillogram we need and count how many divisions it fits into (in our case, 4 divisions). Multiply the price of 1 division by the number of divisions 5*4=20 and determine that the period of the signal in the area under study is 20 milliseconds.

Determination of signal frequency.
The frequency of the signal under study is determined by the usual formula. We know that one period of our signal is equal to 20 milliseconds, it remains to find out how many periods there will be in one second - 1 second/20 milliseconds= 1000/20= 50 Hertz.

Spectrum analyzer

Spectrum analyzer– a device for observing and measuring the relative distribution of energy of electrical (electromagnetic) oscillations in a frequency band.
Low Frequency Spectrum Analyzer(as in our case) is designed to work in the audio frequency range and is used, for example, to determine the frequency response of various devices, when studying noise characteristics, and setting up various radio equipment. Specifically, we can determine the amplitude-frequency response of the audio amplifier being assembled, configure various filters, etc.
There is nothing complicated in working with a spectrum analyzer; below I will give the purpose of its main settings, and you yourself, through experience, will easily figure out how to work with it.

This is what the spectrum analyzer looks like in our program:

What's here - what:

1. Vertical view of the analyzer scale
2. Selecting the displayed channels from the frequency generator and the type of display
3. Working part of the analyzer
4. Button for recording the current state of the oscillogram when stopped
5. Working field enlargement mode
6. Switching the horizontal scale (frequency scale) from linear to logarithmic view
7. Current signal frequency when the generator is operating in sweep mode
8. Current frequency at cursor position
9. Signal harmonic distortion indicator
10. Setting a filter for signals by frequency

View Lissajous figures

Lissajous figures– closed trajectories drawn by a point that simultaneously performs two harmonic oscillations in two mutually perpendicular directions. The appearance of the figures depends on the relationship between the periods (frequencies), phases and amplitudes of both oscillations.

If you apply to the inputs " X" And " Y» oscilloscope signals of close frequencies, then Lissajous figures can be seen on the screen. This method is widely used to compare the frequencies of two signal sources and to match one source to the frequency of the other. When the frequencies are close, but not equal to each other, the figure on the screen rotates, and the period of the rotation cycle is the reciprocal of the frequency difference, for example, the rotation period is 2 s - the difference in the frequencies of the signals is 0.5 Hz. If the frequencies are equal, the figure freezes motionless, in any phase, but in practice, due to short-term instabilities of the signals, the figure on the oscilloscope screen usually trembles a little. You can use for comparison not only identical frequencies, but also those that are in a multiple ratio, for example, if the reference source can only produce a frequency of 5 MHz, and the tuned source can produce a frequency of 2.5 MHz.

I'm not sure that this function of the program will be useful to you, but if you suddenly need it, then I think that you can easily figure out this function on your own.

Audio recording function

I have already said that the program allows you to record any sound signal on a computer for the purpose of further study. The signal recording function is not difficult and you can easily figure out how to do it:

“Computer-oscilloscope” program