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Electronics Lab Equipment
Published in Kevin Robinson, Practical Audio Electronics, 2020
Function generators (or signal generators) provide a convenient source of controllable standard signals for use in the testing and characterisation of circuits being built, modified, or repaired. In addition to standalone units, other equipment often incorporates a function generator as a part of their advanced functionality. Oscilloscopes and signal analysers in particular are commonly found to include this option. Even the 72-7770 DMM (Figure 8.4a) includes a setting which provides a 50Hz square wave output at about 5Vpk−pk. Not the most useful signal for audio work, and rather too limited to be classed as a function generator, but an interesting option on a low-end DMM. Similarly, even oscilloscopes which do not provide an actual function generator usually include a calibration output signal, typically a 1kHz square wave at 5Vpk−pk, designed for adjusting the setup of ×10 probes (see the section on oscilloscopes).
Making Sounds with Analogue Electronics
Published in Russ Martin, Sound Synthesis and Sampling, 2012
Oscillators are related to one of the component parts of analogue synthesizers: function generators. A function generator produces an output waveform, and this can be of arbitrary shape and can be continuous or triggered. An oscillator that is intended to be used in a basic analogue subtractive synthesizer normally produces just a few continuous waveshapes, and the frequency needs to be controlled by a voltage.
An Introduction to Oscillators, Phase Lock Loops, and Direct Digital Synthesis
Published in Nihal Kularatna, Electronic Circuit Design, 2017
The signal source normally found in any analog-type sine wave generator or a function generator is an RC oscillator. Function generators can produce square, triangular, and sawtooth waveforms. A pulse is a square wave generator with a duty cycle of less than 50%; hence, pulse generators can be categorized as function generators. RC oscillators can be further classified as phase shift, Wien bridge, and twin-T.
Experimental investigation on a flapping beam with smart material actuation for underwater application
Published in Mechanics of Advanced Materials and Structures, 2021
Ganesh Govindarajan, R. Sharma
Herein, a simple beam of length of 300 mm, width of 60 mm, and thickness of 3 mm is tested in a glass flume facility present at Department of Ocean Engineering, IIT Madras, India. Material of the beam: stainless steel. Dimension of the flume is: 20 m × 0.6 m × 1.1 m (Length × Breadth × Depth) and it is filled with water and provides the flapping beam sufficient space to move without being affected by the boundaries on both the sides. The beam is also located at mid-depth in the glass flume tank to avoid any interference from the free surface and the bottom of the tank. The experimental setup consists of the power amplifier, function generator, and beam with smart material. Function generator creates the signal to undulate the MFC in the desired forms such as square, sinusoidal, ramp-like waves, etc. Power amplifier increases the signal voltage by 20 times so that high voltage required for efficiently driving the MFC actuators can be achieved. Function generator can create the signal within ±5 V limit. Our experiments focus on the propulsive characteristics of an undulating beam for different operational depths. Herein, the variations of thrust and efficiency with respect to the input voltages and actuation frequency are studied and analyzed in detail and the depth of submergence ‘h’ is defined to be the distance from the undisturbed free surface to the top of the beam. The schematic of submerged beam depths is shown in Figure 1. Image of the experimental setup with focus on uni-morph beam and supporting structure is shown in Figure 2. Deformation of the beam is recorded using a strain gauge. A strain gauge is a device that is used to measure the strain and force on an object. As the beam gets deformed with the smart material, it causes its electrical resistance to change. The underwater dynamics of a MFC unimorph cantilever beam is modeled using the theory of linear bending vibration. As shown in Figure 2, unimorph MFC is fixed with a clamp at the tip of a horizontally located stainless steel beam and strain gauge is attached at head, which functions as a transducer cantilever.
Low-cost multifrequency electrical impedance-based system (MFEIBS) for clinical imaging: design and performance evaluation
Published in Journal of Medical Engineering & Technology, 2018
Gurmeet Singh, Sneh Anand, Brejesh Lall, Anurag Srivastava, Vaneet Singh
Reconstructed image quality in an EIT system depends on the accuracy of the data collection system and the image reconstruction techniques used. EIT instrument is an important element of any EIT arrangement. Accuracy of the data collection system of EIT also depends on various other important parameters along with the instrumentation of the EIT. These parameters are type of electrodes used for capturing data, their positions, number of electrodes used, electrodes properties i.e. contact impedance, electrode area and boundary shape under the electrode [29]. The quality of the reconstructed images is a function of gain of the system, frequency band, signal to noise ratio of the instrumentation amplifier, VCCS and filters used. VCO is designed to generate a signal of 1 kHz–2 MHz with IC MAX038 from Analog Devices. It is a high-frequency accurate function generator, capable of producing precise, high-frequency triangle, saw tooth, sine, square, and pulse waveforms using very less external components. The output of VCO is applied to the input of VCCS to produce a constant current. In first projection (P1), a constant current of 1 mA is injected into two of 16 stainless steel electrode nos. 1 and 2 as shown in Figure 2(a) of the phantom tank in adjacent current insertion scheme. The developed potential is captured from the left over electrode pair 3–4, 4–5, 5–6 and so on. In next projection (P2), current is fed to next current electrode pair (electrode nos. 2 and 3) and developed potential is measured from the other electrodes (electrode pair nos. 4–5, 4–5, 5–6 and so on) using neighbouring electrode switching protocol. In the similar manner remaining projections are completed, by injecting current on all the remaining electrodes pair and developed potential were measured in the left behind electrode pairs. Similar to projection P1 and P2 as shown in Figure 2, for a 16 electrode adjacent current injection method, there are a total of 16 current projections (P1–P16). In each projection, there are 13 differential voltage set measured on the voltage electrodes. So for a 16 electrode EIT system in neighbouring method, one complete set of surface electrode potential consists of 16 × 13 = 208 measurements. Out of these only 104 readings are independent of each other according to reciprocity theorem. 16 × 1 Multiplexer is used for automatic switching of voltage electrodes and current electrodes. NI high-speed DAQ is used to control these MUX. The surface potential captured from the surface electrodes is fed to 50 Hz notch filter (IC AD811) for noise reduction after proper amplification using an instrumentation amplifier developed using IC INA114, and IC OPA633 used as a buffer amplifier.