Engineering, Polytechnic and Vocational Training Equipment-> Fiber Optic Communication Trainers

[1]   Click to Enlarge FIBER OPTICS CHARACTERISTICS STUDY TRAINER. MODEL IBL-FOT-1 From this kit you can perform the following experiments 1. Calculation of Power from two different lengths of Fiber cable. a) Measurement of phototransistors current for different lengths of Fiber cable. b) Calculation of launch power for each light source. c) Calculation of attenuation coefficients (a) of fiber, for different light sources, 2. Measurement of Rise and fall time for various detectors and light sources. a) Measurement and calculation to determine which light source and detector combination is faster. b) Measurement and calculation to determine upper frequency 3dB Bandwidth, for different light sources. c) Measurement and calculation to determine upper frequency 3dB Bandwidth, for different detectors. 3. Comparisons of the Transmission characteristic of a continuous Fiber cable Vs those with spliced cables. 4. Study of Index matching with splices includes, a) Measurements of phototransistor current when Fibers are spliced together with and without index-matching, Comparison of the transmission characteristics of a Fiber splice with and without index matching includes calculation of Fresnel?s reflection. This unit is assembled in an ergonomically designed cabinet, with necessary power supplies and associated emitters, detectors, multi mode transmission cables. You need optional signal sources, Oscilloscope, a high impedance mulitmeter as additional equipment to successfully conducting the above objectives. Specification: Types of Transmitters:- Infra Red : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Visible RED : Fiber optic Red 635 nm peak wavelength housed in FC adapter. Orange : Fiber optic Orange 600 nm peak wavelength housed in FC adapter. Blue : Fiber optic Blue470 nm peak wavelength housed in FC adapter. Green : Fiber optic Green 565 nm peak wavelength housed in FC adapter. Laser Diode/monitor : Fabry-Perot (FP) laser diode. Multiple Quantum Well (MQW) structure and built-in InGaAs monitor photo diode. 1310 nm peak wavelength housed in FC adapter. Forward Current of LD :150 mA Types of Receivers:- Photodiode : Peak sensitivity 880nm Phototransistor : Peak sensitivity 850nm Laser Diode/monitor : Fabry-Perot (FP) laser diode. Multiple Quantum Well (MQW) structure and built-in InGaAs monitor photo diode. 1310 nm peak wavelength housed in FC adapter. Forward Current of PD :10 mA Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12 V See Enlarge Click to Enlarge FIBER OPTIC ANALOG TRANSMITTER RECEIVER TRAINER. MODEL IBL-FOT-2 This trainer is intended to study the analog data transmission principles. Although most fiber optic systems are digital in format, there are few analog applications. Designing an LED / LASER driver for an analog fiber optic system is comparable to designing an electronics CLASS-A amplifier. It must have adequate bandwidth, good linearity, and non-clip for the range of input signals. This trainer provides a means to study and experiment how an analog signal can be transmitted over a multimode 1000 mm multi-mode plastic fiber cable. Study of Fiber Transmission circuits includes, and Calculation of 3dB bandwidth. This trainer includes an analog transmitter, transmitting media, and a receiver. The analog transmitter consists of an LED (680 nm) / IR emitter (800nm) as an optical driver. The transmission media is 1000 mm multi-mode plastic fiber cable. The receiver consists of a linear amplifier. This unit is assembled in an ergonomically designed cabinet, with necessary power supplies and associated emitters, detectors, multi mode transmission cables. You need an optional signal source, Oscilloscope, a high impedance mulitmeter as additional equipment to successfully conducting the above objectives. Specification: Types of Transmitters:- Infra Red : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Visible RED : Fiber optic Red 635 nm peak wavelength housed in FC adapter. Types of Receivers:- Photodiode : Peak sensitivity 880nm Phototransistor : Peak sensitivity 850nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 12 V See Enlarge Click to Enlarge FIBER OPTIC DIGITAL TRANSMITTER AND RECEIVER TRAINER MODEL IBL-FOT-3 The word digital in fiber optic means, much the same as it does in electronics. Digital gates, circuits or systems are those, in which there are two defined states. A LOW or a digital ZERO and a HIGH or a digital ONE. In all digital systems, LOW or HIGH, low does not necessarily means a ZERO voltage or ZERO optical signal. A digital ZERO means, a LOWER state than the digital ONE state. Digital Transmitter in this trainer consists of the following circuits. Using them the student studies different types of different transmitting circuits. I. Single switching circuit, II. Push-Pull driving circuit, III. Ten-megabit push-pull drive circuit. Transmission is done through 1000mm multi-mode plastic fiber cable. The digital receiver consists of (a) CMOS receiver, (b) discrete bi-polar transistor. This unit is assembled in an ergonomically designed cabinet, with necessary power supplies and associated emitters, detectors, multi mode transmission cables. You need optional signal sources, Oscilloscope, a high impedance mulitmeter as additional equipment to successfully conducting the above objectives. Specification: Types of Transmitters:- Infra Red : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Visible RED : Fiber optic Red 635 nm peak wavelength housed in FC adapter. Types of Receivers:- Photodiode : Peak sensitivity 880nm Phototransistor : Peak sensitivity 850nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC – FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12 V See Enlarge Click to Enlarge FIBER OPTIC VOICE / TONE TR / RX TRAINER. MODEL IBL-FOT-4IR Introduction: Basically, a fiber optic data link contains three main elements: a transmitter, an optical fiber and a receiver. The transmitter takes data previously in electrical form and transforms it into optical (light) energy containing the same information. The optical fiber is the medium, which carries the energy to the destination (receiver). At the receiver, light is converted back into electrical form with the same pattern as originally fed to the transmitter by the person who sent the message. The advantages of optical fiber are that it allows light to be routed around corners and transported through obstructions (such as walls in buildings), just as household electrical and telephone wiring do, but with much greater signal-carrying capacity, plus being able to operate at greater distances and on foggy and rainy days. This trainer is intended to experiment some of the above, described topics. The fiber Optic Voice Link trainer consists a (a) transmitter, (b) transmission media (fiber optic cable) and (c) a receiver. The transmitter consists of a microphone, pre-amplifier, signal conditioner, Optical source (IR 800nm). The transmission media is 1000 mm multi-mode plastic fiber cable. The receiver consists of an optical detector (Photo diode / phototransistor), pre-amplifier, power amplifier and a loud speaker. The fiber Optic Voice Link trainer consists of a microphone with necessary pre-amplifier, at the transmitter end and an optical detector at the receiver. The optical fiber is used as transmission media. The received signal is further amplified and the audio output is connected to a speaker. There by enabling you to transmit an audio signal and receive at the receiver. This unit has an additional facility to connect a sine wave source from any external function generator as a transmitter. This facility allows you to study the frequency response of the transmission characteristics in the audio range. This unit is assembled in an ergonomically designed cabinet, with necessary power supplies and associated emitters, detectors, amplifiers, multi mode transmission cables. You need optional signal sources, Oscilloscope, a high impedance mulitmeter as additional equipment to successfully conducting the above objectives. Specification: Transmitter : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter.Receiver : Photodiode with Peak sensitivity 880nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12 V Microphone with proper signal conditioner Speaker assembly with suitable power amplifier. All the above are available in an ergonomically designed cabinet. See Enlarge Click to Enlarge FIBER OPTIC (1000?m) DIGTIAL DATA TX / RX TRAINER. MODEL IBL-FOT-5 This trainer is intended to study serial communication between a Microprocessor trainer Model MPT-85 and a PC. The system consists of a built in Microprocessor to handle the input output protocols. The medium of communication between the processor and the PC is through a fiber optic link. Necessary software and firmware is supplied along with the trainer. The trainer requires understanding of 8085 Microprocessor instruction set. Specification: Transmitter : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter Receiver : Photodiode with Peak sensitivity 880nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12 V Microprocessor : Model MPT-85 with necessary peripherals for I/O Operations. See Enlarge Click to Enlarge FIBER OPTIC DATA MULTIPLEXER TX / RX TRAINER. MODEL IBL-FOT-6 Mulitiplexer by the very name, suggests more than one signal is transmitted through the same fiber optic cable. This trainer helps to view how signals from different signal sources are multiplexed and transmitted. This trainer has 16 channel Mulitiplexer. 16 independent external signals from external source can be applied as input to this data Mulitiplexer. The necessary timing generator and sync signal generator are included on board. This is used as synchronizing signal for the receiver for decoding purpose. In order to demonstrate this principle, 3 different signals are generated onboard, namely a pseudo-random bit sequence (PRBS) generator, a pulse and SINE generator of 1 kHz. Using these three signals, the user can start study of Mulitiplexer and De-Mulitiplexer. An external dual beam oscilloscope is required for observing the input and output signals. For ease of study, both transmitter and receiver are assembled on the same board. Specification: Transmitter : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Receiver : Photodiode with Peak sensitivity 880nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12 V Generator : Built-in SINE, PULSE, PRBS See Enlarge Click to Enlarge FIBER OPTIC PULSE CODE MODULATION TRAINER. MODEL IBL-FOT-7 Introduction: PULSE-CODE MODULATION (PCM) refers to a system in which the standard values of a QUANTIZED WAVE are indicated by a series of coded pulses. There are numerous ways to quantize an incoming wave. When these pulses are decoded, they indicate the standard values of the original quantified wave. The study of PCM trainer is all about these methods. These codes are binary. The entire range of amplitude (frequency or phase) values of the analog wave can be arbitrarily divided into a series of standard values. Each pulse of a pulse train takes the standard value nearest its actual value when modulated. Then the modulating wave can be faithfully reproduced. Each pulse is given whatever standard value is nearest its actual instantaneous value, and the same amplitude range has been divided into 256 standard levels using 8 element binary code. The system does, of course, have some distortion introduced by quantizing the signal. Both the standard values selected and the sampling interval tend to make the reconstructed wave depart from the original. This distortion, called QUANTIZING NOISE, is initially introduced at the quantizing and coding modulator and remains fixed throughout the transmission and retransmission processes. Making the standard quantizing levels closer together can reduce its magnitude. About the system: The purpose of this trainer Model FOT-7 is to introduce you to the Pulse Code Modulation (PCM) and demodulation technique. A multimode Fiber Optic cable is used for data transmission and reception. In this trainer, you will understand and investigate the following processes. All the major blocks of this trainer are designed from fundamental building blocks instead of using a dedicated CODEC. As a result, all the blocks of CODEC are dissected and are available as separate building blocks for study. This facilitates the student to understand the quantization process and view the quantified and encoded data using 8 bit LED displays at the transmission side. Observe the serial transmission and reception of this quantified decoded data at a test point, observe the decoded 8 bit received data on LED display etc. This data is further reconstructed and the original signal is available at an output terminal for analysis. As a result of this design, the student can see various stages of the PCM transmission and reception processes for himself. Features of PCM blocks are Digitization of an analog signal, Observe the quantization (encoding) of incoming signal, Measurement of quantization noise, Serialization of quantized signal for onward transmission, Serial data capture, Decoding of quantified signal, Observation of received signal, Reconstruction of received signal, and Study of aliasing. In order to achieve the above, the trainer has necessary built in input signal sources. (a) Continuously variable analog input in the range of 0 to 5 VDC, (b) Function generator with Sine, and Square wave inputs in the range of 200Hz to 20KHz (c) Microphone input after proper signal conditioning, for voice transmission and (d) Provision to connect an external signal source. The output of the transmitted and received signals, decoded signal and finally the reconstructed outputs can be observed on the oscilloscope. In order to observe the sequence of events taking place, there are two types of clocks provided one operating at 200KHz, the other at 1Hz. During slow clocking it is possible to observe the signal flow at various test points as detailed below. (a) Quantization process (b) Serial transmission (c) Decoded output and (d) Reconstructed output. (e) A power amplifier with speaker to hear the voice reception ( when sampled at 200KHz) This trainer comes with completely self-contained systems with built-in power supplies, signal sources, input output test points for signal observations, a microphone with proper signal condition, a power amplifier with speaker etc. This requires an optional external Dual beam oscilloscope to observe the PCM signal transmission at different stages of modulation and demodulation processes. Specifications:- Transmitter : Fiber optic InfraRed LED 820nm peak wavelength housed in FC adapter. Receiver : Photodiode 400 to 1100nm. Frame size : 8 Bit with LED indicator for frame marker. Sampling rate : 250KHz. Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter On board signal generator : Variable SINE, SQUARE @ 200Hz Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Numerical aperture : 0.5 Acceptance angle : 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Power supply : 5V and 12V Input sources: 1. Built-in Function generator with SINE, and SQUARE waveforms. 2. Frequency: Variable frequency of 250Hz to 2KHz 3. Amplitude: Variable in the range of 0 to 5 Volts 4. Continuously variable DC source : 0 to 5V DC 5. Provision for connecting external signal source 6. Microphone with proper signal conditioner Output: 1. 8 bit LEDs to display Quantized data 2. 8 bit LEDs to display decoded data 3. Power amplifier with speaker 4. Frame timing LED to display clock signal 5. Synchronizing signal LED 6. Speaker assembly with suitable power amplifier. Built-in power supplies. All the above are available in an ergonomically designed cabinet. See Enlarge Click to Enlarge NUMERICAL APERTURE MEASUREMENT DEVICE. MODEL IBL-FOT-8 This is a mechanical arrangement to hold the fiber optic cable. It is possible to swing the incidence angle of the fiber light from 0 to 1800 in the horizontal plane, on to the detector. Using this device, it is possible to measure the critical angle of transmission. This information is useful to determine collection efficiency from an emitter and photo detector. The critical angle of a fiber depends on the core?s and cladding?s refractive indices. See Enlarge Click to Enlarge INDUSTRIAL APPLICATION OF FIBER OPTIC SYSTEMS. SPEED CONTROL OF A DC MOTOR. MODEL IBL-FAP-1 This trainer is a combination of two instruments. 1. Speed Control of DC Motor Transmitter Model EBS-24 and 2. DC Motor speed control trainer (for fiber optic applications) Model DSC-2 About the PIC controller: This trainer has a built-in PIC controller. It is programmed to accept 4 bit binary data as its input. The PIC is programmed to accept the status of these 4 binary switches and produces a PWM train of pulses at its output. This train of pulses is further processed through a fiber optic transmitter for onward transmission to a receiver using fiber optic cable. About DC Motor interface: This trainer is intended to vary the Speed control of a DC motor using Fiber optic communications. The fiber optic link from any PWM transmitter fed as input to this speed control trainer. This trainer is same as DC motor speed control trainer PE-10, except that this has an additional facility to connect fiber optic interface also. Read explanations for PE-10. This is a Microcontoller based speed control demonstrator. This unit consists of 3 blocks. (a) Microcontroller based PWM Transmitter, (b) Fiber optic receiver with PWM demodulator, and (c) a motor tacho-generator drive assembly. This makes use of Pulse width modulation technique. The transmission of digital data from the Microcontoller is serialized and passes through Fiber Optical cable. The received signals are used to control the speed of DC Motor. This has two parts (a) a Microcontoller (b) the DC motor interface system. This DC drive has built in Tachogenerator, with Digital RPM indicator. Specifications: Transmitter : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Receiver : Photodiode with Peak sensitivity 880nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber optic cable : 1000 mm multi-mode plastic 1-Meter fiber cable Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Microcontroller : PIC based Duty cycle of PWM : Variable in the range of 10% to 90% Pulse amplitude : TTL Pre-settable : in the range of 0 to F hex Speed increment : By single pulse increment or decrement Motor : A permanent magnet DC motor Speed : In the range of 30 to 530 RPM operating at 24 V DC Feedback signal : Using Tacho-geneartor Power supply : 5V and 12 V Speed measurement : By using an external voltmeter. This is supplied along with the trainer See Enlarge Click to Enlarge SPEED CONTROL OF A DC MOTOR. MODEL IBL-FAP-1 This trainer is a combination of two instruments. 1. Speed Control of DC Motor Transmitter Model EBS-24 and 2. DC Motor speed control trainer (for fiber optic applications) Model DSC-2 About the PIC controller: This trainer has a built-in PIC controller. It is programmed to accept 4 bit binary data as its input. The PIC is programmed to accept the status of these 4 binary switches and produces a PWM train of pulses at its output. This train of pulses is further processed through a fiber optic transmitter for onward transmission to a receiver using fiber optic cable. About DC Motor interface: This trainer is intended to vary the Speed control of a DC motor using Fiber optic communications. The fiber optic link from any PWM transmitter fed as input to this speed control trainer. This trainer is same as DC motor speed control trainer PE-10, except that this has an additional facility to connect fiber optic interface also. Read explanations for PE-10. This is a Microcontoller based speed control demonstrator. This unit consists of 3 blocks. (a) Microcontroller based PWM Transmitter, (b) Fiber optic receiver with PWM demodulator, and (c) a motor tacho-generator drive assembly. This makes use of Pulse width modulation technique. The transmission of digital data from the Microcontoller is serialized and passes through Fiber Optical cable. The received signals are used to control the speed of DC Motor. This has two parts (a) a Microcontoller (b) the DC motor interface system. This DC drive has built in Tachogenerator, with Digital RPM indicator. Specifications: Transmitter : Fiber optic Infra Red 820 nm peak wavelength housed in FC adapter. Receiver : Photodiode with Peak sensitivity 880nm Connection : Plastic fiber optic package, suitable for PMMA cable, housed in FC Adapter Fiber optic cable : 1000 mm multi-mode plastic 1-Meter fiber cable Fiber connector : Industry standard FC ? FC connector Fiber optics cable type : Plastic optical cable, step index, multimode. Core refractive index : 1.492 Clad refractive index : 1.406 Acceptance angle : Within 60 degrees Core diameter : 1000mm Fiber diameter : 2.2mm Fiber length supplied : 1 meter and 3 meter Microcontroller : PIC based Duty cycle of PWM : Variable in the range of 10% to 90% Pulse amplitude : TTL Pre-settable : in the range of 0 to F hex Speed increment : By single pulse increment or decrement Motor : A permanent magnet DC motor Speed : In the range of 30 to 530 RPM operating at 24 V DC Feedback signal : Using Tacho-geneartor Power supply : 5V and 12 V Speed measurement : By using an external voltmeter. This is supplied along with the trainer See Enlarge Click to Enlarge TEMPERATURE CONTROL TRAINER. MODEL IBL-FAP-2 This is a Microcontroller based temperature trainer. This trainer has an RTD as temperature sensing element. This has facility to switch ON ?OFF 300Watts heater once the desired temperature is reached. The transmission of the data is through Fiber optic cable. This unit is supplied with necessary heater, RTD, hotwater bath and power supplies. See Enlarge Click to Enlarge LASER TRAINER. MODEL IBL-LT-1 LASER (Light Amplification Simulated Electric Radiation) is a device designed to generate light with special and unique characteristics. The LASER can be used to perform surgery, melt metals, cut materials, mark and scribe information on parts, transmit information over long distances and measure distances very precisely. The purpose of this trainer is to experiment and to allow you to become LASER literate, and become aware how they work. We use class II HeNe laser source. It is harmful to view LASER beam with naked eye. Using this trainer the following tasks can be accomplished. List of Experiments: Estimate the output beam diameter by observing the spot in both a lighted and darkened room. Calculate the irradiance produced by the beam at a given distance from the LASER. Produce interference effects with the coherent light from HeNe LASER. Produce diffraction effects as the coherent light from a HeNe LASER bends around edges of obstacles. Measure the diameters of an expanded HeNe LASER beam by taking " pin point" power readings at different locations within the beam. Calculate the index of refraction for water. Measure the critical angle of incidence for water / air interface. Determine the focal length of a positive lens. Construct an up collimator and use it to expand the laser beam and reduce the beam's divergence. Measure the angles of incidence and reflection from a specular reflector and compare the values. Study the characteristics of concave and convex mirror surfaces. Observe the effect of light absorption by crossed polarizers. Demonstrate the transmission of a signal over a laser beam by modulation of the laser's power supply. Specifications: LASER: Low power, HeNe Concave - 1 Classifiction: Class II type. Convex - 1 Color: Red-Orange beam. Flat lenses - 1 set Lenses & Mirrors Light filter - 2 Nos. Beam power: < 1mW in visible spectrum. Safety shutter provided. See Enlarge Click to Enlarge LASER TRAINER USING SEMICONDUCTOR LASER. MODEL IBL-LT-2 This laser trainer has a semiconductor diode. The laser used in this is based on telcordia reliability. It operates on 1310 nm Multiple Quantum Well, (MQW) structured Fabry-Perot (FP) laser diode with InGaAs monitor PIN-PD. The peak output power of this is 5mW. Using this Optical measurement experiments can be conducted with optical accessories as listed below. This is no substitute for an actual HeNe laser beam. This trainer is supplied with the following accessories. Specifications: Concave ? 1 Convex ? 1 Color: Red beam. Flat lenses - 1 set Lenses & Mirrors Light filter - 2 Nos OPTIONAL INTERFACE FOR LASER TRAINER MODEL LT-1 & LT-2 VOICE TRANSMITTER AND RECIEVER: This is a demonstration system. This consists of audio using Microphone with necessary preamplifier etc, is modulated on laser beam and transmitted. The same is received at the receiver. This consists of demodulator, power amplifier speaker. See Enlarge [1] Go to Top