The low-frequency signal generators
The low-frequency signal generator is a portable source of electrical frequency oscillations (sound, ultrasound). In the basic mode, a sinusoidal signal, in an additional mode, a square wave signal. Low-frequency signal generators are used to regulate and adjust systems and devices that are used in the radio electronic industry, in communication devices, in various automatic, computing, measuring devices, and in the instrument-making industry. In the low-frequency generator, it is possible to smoothly adjust the output voltage by means of a dial indicator. The LF generator can memorize the settings of the device, system, thus saving much time for the engineer.
The low-frequency signal generator has excellent operating conditions, as it can withstand significant temperature changes: from minus 10 to plus 50 degrees Celsius, with relative humidity of 95% and atmospheric pressure up to 800 mm. Mercury column.
The generator is a radio electronic device, consisting of various functional units.
- The driving oscillator is a tunable frequency oscillator. Stabilization of the signal amplitude at the output is automatic. The power amplifier provides a given power in the load circuit, eliminates the influence of the load on the master oscillator and its operation. The amplifier looks like an operational amplifier, covered by a negative feedback.
- Output signal generator (rectangular) – converts the sinusoidal signal into a rectangular one. A rectangular signal is formed in series, bilaterally limiting the sinusoidal signal by diodes, and then amplifying the limited signal by means of two differential amplifiers on transistors.
- The power supply unit consists of two multipolar sources, adjustable, with a constant voltage of 24 V. It has protection against electrical surges.
- An amplifier of generators is use for obtaining an output voltage of up to 25 V, at frequencies of 10 Hz to 10 MHz, with a resistance of one kΩ.
- Also, low-frequency signal generators include an output attenuator, various modulators, time interval generators, frequency synthesizers and other devices.
There is low-frequency generator in which the output signal is generated by a digital method or operating in the optical range.