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Stereo audio Compressor
2008-05-13 03:34:00 An Audio Compressor is an essential tool for audio processing and it is commonly found in recording studios. Most recording studios have a selection of compressors, each chosen for some specialized feature or nuance. Your home may not be a professional recording studio, but you do need our Stereo Compressor, so read on.As the device's name implies, the Stereo Compressor compresses or limitsthe dynamic range of an audio signal. (Make sure you read the sidebar How Compressors Work.) In a recording studio, compressed audio prevents tape-recorder overload during loud passages without losing quiet passages in the noise floor (hiss). Before compressors were invented, the recording engineer would ride the gain by manually adjusting the signal level.How it is doneThe block diagram of the Stereo Compressor Is shown above. The input signal is fed to a voltage-controlled amplifier (VCA) that has a nominal gain of unity. Some of the output signal is fed to a precision rectifier followed by a...
Dynamic Audio Compressor
2008-05-13 03:22:00 Dynamic compander is a special amplifier whoose gain is controlled with the level of the signal input to the same amplifier. The change to the gain is made "slow" so that the amplifier has a linear response locally in time, but on a larger time scale (seconds) its gain varies according to some law. Generally, one differs two kinds of companders: compressors and expanders. A compressor "squeezes" the dymnamic range of an audio signal so that the ratio between the maximum and minimum levels becames smaller, while an expander "expands" the dynamic range. Dynamic changes can be made linear or nonlinear.Typical application of companders is in optimizing the noise performance of record/playback procedure in audio tape decks (trade marks: dbx, Dolby,...). The other common application is in audio telecomunications where the transfer channel has a limited bandwith, such as radio-transcievers, computer chat etc.In the following example I present a scheme (below) of a compressor which is capab... More About: Audio , Dynamic , Compressor
2.4 GHz Signal Generator
2008-05-13 02:40:00 This signal generator uses a free-running L-band VCO as it's source. It has a 1 KHz modulator, and a variable-level amplifier (-20 dbm to 3 watts), making it suitable as a source for antenna range measurements, which was it's design intent.It is reasonably stable for an unlocked oscillator, drifting no more than 300 KHz or so over an hour's time. This is stable enough for instrumentation measurements (like SWR and attenuation). An example of it's use are these sample SWR measurements made on several 23 cm antennas.The small consumer electronics power module shown here is it's power source.Download Generic Schematic for 1.2 GHz and 2.4 GHz Signal Generator This VCO-controlled signal source was designed as an instrumentation source; this one has no power amplifier module, and therefore max out from the MMIC final is about 70mw.MMIC use Sirenza 6486 on 2.4 GHz and Sirenza 6386 on 1.2 GHzThis is the layout on the inside, with the power amplifier module and 12v regulator attached to ...
RF Cables
2008-05-12 11:32:00 Coaxial cables are used for all antenna connections. There are three types in common usage and they are listed in the table below. Cable losses (the amount of signal lost in the cable) are significant at the frequency of 1800MHz used by Orange (Remember many Radars work at lower frequencies than this - never mind phones.). To reduce cable losses cable runs should always be kept as short as possible.When installing coaxial cable you should remember than its characteristics depend upon its shape - so don't do anything to bend it sharply or to squash it. Each area of damage introduces reflections in the signal and reduce the efficiency of the cable. Typically RG58 type cables have a minimum bending radius of about 3cm.In the table below cable losses are described as High, Medium, or Low at 1800MHz.Cable Attenuation TableThe table below has been taken from a number of (sometimes contradictory) sources and should be read as a guide rather than a product specification. That said I... More About: Cables
Low Power RF Amplifier for 88-108 MHz
2008-05-11 20:46:00 This application use a common NPN RF transistor called 2SC1970. You can also use other transistors like 2N4427 and some others. Check datasheets to se how much power the transistor can handle. 2SC1970 will handle 1.3W and 2SC1971 up to 6W. Most transistor has a power gain of 10dB meaning 10 times power amplification.This is the reason why you must use several stages to achieve a strong transmitter. In this construction we are getting higher power then ever and you must be careful with the transistor. A 50 ohm dummy load MUST be used while testing, else the final transistor will break. An antenna can be used but the antenna must be properly made else the transistor will break.Hardware and SchematicIn all RF system and specially in RF amplifiers, it is very important to have a stable power supply and making sure you won't get any RF out on the power line. The Capacitor C12 and C13 will stabilise the DC power supply. L1, C10, C11 and L3 with C8, C9 will also prevent RF from leaking o... More About: Power , Amplifier
WLAN High Linearity Power Amplifier
2008-05-11 20:14:00 The SST11LP12 is a high-power, high-gain power amplifier based on the highly-reliable InGaP/ GaAs HBT technology. The SST11LP12 can be easily configured for high-power, high-efficiency applications with superb power-added efficiency while operating over the entire 802.11a frequency band for U.S., European, and Japanese markets (4.9-5.8GHz). It typically provides 35 dB gain with 16% poweradded efficiency @ POUT = 23 dBm.The SST11LP12 has excellent linearity, typically ~4% added EVM at 21 dBm output power which is essential for 54 Mbps 802.11a operation while meeting 802.11a spectrum mask at 23+ dBm. SST11LP12 also has wide-range (>20 dB), temperature-stable (~1 dB over 85°C), singleended/differential power detectors which lower users’ cost on power control.The power amplifier IC also features easy board-level usage along with high-speed power-up/ down control. Ultralow reference current (total IREF 802.11a WLAN transmitter and access point applications. Figure 1The SST11LP12 is... More About: Power , High , Amplifier
Microwave Power Dividers
2008-05-06 22:57:00 Power dividers and combiners are used in microwave frequencies because of the different behavior of circuits. In microwave frequencies, the modeling of the circuits are different from the expected lumped model. Therefore, power dividers in microwave frequencies are not just resistive power dividers as in the low frequency or DC model.The important issues while using power dividers, are the specifications or properties of the dividers. In microwave frequency applications, for example power can be reflected from the output ports. Then to avoid the reflected power expected power divider should satisfy the maximum power transfer theory, which says the impedance of the load should be the complex conjugate of the impedance seen from the load end when load is not connected. This is called "matching" of the ports. This leads to transferring maximum power to the load and because of no reflection, avoid to burn out the power supply. Also, again for maximally transfer the power to the output p... More About: Power , Microwave
What Is Satellite Telemetry
2008-05-03 22:28:00 Transmitters, also called PTTs (Platform transmitter terminals) are attached to the animal whose long distance movements are to be studied. Once they are turned on, the transmitters send high frequency signals which are received by polar orbiting weather satellites. ARGOS, a French company, has equipment on board these satellites for tracking animal movements.The transmissions are first decoded to identify the transmitter, each of which has a unique code and then the position of the transmitter is calculated. The data is then downloaded by ARGOS. Once the data is received, the latitudes and longitudes can be plotted on a map and the migratory routes of the animals can be traced. The data is classified by ARGOS depending on the quality of the data received by the satellite. LC 1, 2 and 3 are the best quality points and have an error radius of 1000m, 350m, and 150m respectively.In marine turtles, the transmitters also have a salt water switch which is turned on when the turtle is und... More About: Satellite
Wireless Telemetry System With Frequency Division Multiplexing
2008-05-03 17:09:00 This Wireless Telemetry System acquires several different sensor inputs, FM modulates each level by manipulating Direct Digital Synthesis increment values, transmits the resulting signal on a commercial FM radio band, and receives and decodes the original sensor levels.Multi sensor Wireless telemetry system with Frequency Division Multiplexing (FDM).Wireless Telemetry System - LinkRelated Post:Miniature Telemetry Transmitter Applications - LinkTelemetry Transmitter - Link
Electronic Fax Circuit
2008-05-01 22:55:00 You can build the electronic fax circuit below to cut wear and tear on your fax machine while saving power. If your fax machine has a dedicated phone line, the circuit intercepts the incoming ring signal and powers up the fax machine in time to receive the fax. It then turns off the fax machine after a predetermined time and awaits the next incoming fax. A relay in the line-cord circuit of the machine provides the turn-on and -off functions. If you build the fax saver in a small, plastic, outlet-type box, you can plug the fax machine into the box and wire the phone line in parallel with the machine's phone line.The electronic fax circuit incorporates protection against phone-line transients and draws its power from the normal 48V dc on the phone line; you thus need to exercise care in relay selection. Suitable relays are available at low cost from major distributors. The circuit function centers on a long-countdown device, IC1, whose overall delay depends on the external passive co... More About: Electronic , Circuit
Create an Electronic Circuit Design in Minutes
2008-04-30 14:00:00 If you want to create a Printed Circuit Board (PCB), You need circuit software for drawing the Circuit design in order to translate the circuit boards prototype into a schematic diagram. Start with the exact template you need?not just a blank screen. Then easily customize to fit your needs with thousands of ready-made symbols you can stamp directly onto your image.Create electrical and electronic circuit diagrams, schematics, and more with SmartDraw.Download SmartDraw Electronic Circuit Design Software FREE!Discover why SmartDraw is the World's Most Popular Business Graphics Software. Our electronic circuit design software is fast and easy.You can try SmartDraw electronic circuit design software FREE with no obligation. More About: Minutes
Very Low Power FM Transmitter on UHF Band
2008-04-30 13:47:00 CC1050 (CHIPCON) is RF Integrated Circuit UHF transmitter designed for very low power and very low voltage wireless applications. The circuit is mainly intended for the ISM Industrial, Scientific and Medical) and SRD (Short Range Device) frequency bands at 315, 433, 868 and 915 MHz, but can easily be programmed for operation at other frequencies in the 300-1000 MHz range.The main operating parameters of CC1050 via an easy-tointerface serial bus can be programmed, thus making CC1050 a very flexible and easy to use transmitter. In a typical system CC1050 will be used together with a microcontroller and a few external passive components. CC1050 is based on Chipcon?s SmartRF® technology in 0.35 µm CMOS.Application Schematic and DatasheetFeatures? True single chip UHF RF transmitter? Very low current consumption? Frequency range 300 ? 1000 MHz? Programmable output power ?20 to 12 dBm? Small size (TSSOP-24 package)? Low supply voltage (2.1 V to 3.6 V)? Very few external components require... More About: Band , Power , Transmitter
Audio Video Distribution Amplifier
2008-04-21 00:28:00 With the amount of equipment in home entertainment centers today the need to be able to vary the gain of the audio or video signal is needed. I found this particular circuit helpful when used in conjunction with the Universal Descrambler and a Stabilizer circuit I built for making copies of video tapes. It not only allowed me the ability to fine tune the video strength it also helped me increase the recorded audio which typically becomes poor when making tape copies.This circuit is an audio video distribution amplifier that splits to other channel for audio and video. Circuit operation is straight forward for amplifier circuits. The second channel for the audio amplifier is made up of the same components except the other half of IC1 is used. Pin 6 & 5 are inputs and 7 is the output. More About: Video , Audio , Distribution , Amplifier
Miniature Telemetry Transmitter Applications
2008-04-20 23:49:00 IntroductionThe goal of this project was to build a small, cheap, light-weight telemetry transmitter to attach to a small bird.Specifically:* Telemetry Tranmission should be tuned to the 2-meter band.* Battery life in the field should exceed 3 months without replacement.* Range should be 500 meters.* Weight less than 10 gramsThe CircuitThis wireless telemetry transmitter circuit shown was originally designed by William Cochran (1), with modifications by Charles Walcott. Physical layout of the circuitA test version of the circuit was constructed in a 5x2 chunk of IDC female header plug so that the crystal and transistor could be easily changed. The tank coil can be seen on the right in either photo below. The brown/white wire to the right is the antenna. Power supply leads extend to the left.The final circuit version of telemetry application was built using the crystal as the physical substrate.Reference1. William W. Cochran; Rexford D. Lord, Jr., A Radio-Tracking System for Wild Ani... More About: Applications , Miniature , Transmitter
Telemetry Transmitter
2008-04-20 23:36:00 Telemetry or "remote measurement" is a highly automated communications process by which measurements are made and other data collected at remote, inaccessible or dangerous places, and then relayed by a telemetry transmitter to receiving stations for display, monitoring, and recording. The original telemetry systems were termed "supervisory" because they were used to monitor electric power distribution. Communication channels form a major part of any telemetry system, as it involves measurement of the transmission of data over various mediums.Telemetry transmitter is the instrument used for recording the readings of an instrument and transmitting them by radio or wireless frequencies. Technically, when relaying data, it is necessary for the transmitter to identify the data item corresponding to each segment of the bit stream. This is done by inserting a synchronization bit string into the telemetry stream on a regular basis, usually at the beginning or end of each repeating cycle. Th... More About: Transmitter
RF Signal Generator
2008-04-20 19:30:00 A signal generator, also known variously as a test signal generator, function generator, tone generator, arbitrary waveform generator, or frequency generator is an electronic device that generates repeating electronic signals (in either the analog or digital domains). They are generally used in designing, testing, troubleshooting, and repairing electronic or electroacoustic devices; though they often have artistic uses as well.There are many different types of signal generators, with different purposes and applications (and at varying levels of expense); in general, no device is suitable for all possible applications.General purpose signal generatorsFunction generatorsA function generator is a device which produces simple repetitive waveforms. Such devices contain an electronic oscillator, a circuit that is capable of creating a repetitive waveform. (Modern devices may use digital signal processing to synthesize waveforms, followed by a digital to analog converter, or DAC, to produc... More About: Generator , Signal
Categories of Quartz Crystal Oscillators
2008-04-20 19:11:00 Basic Technology of Quartz Crystal OscillatorsQuartz crystal oscillator is a timing device consisting of quartz crystal resonator and an oscillation circuit to generate an output waveform at specified frequency. It can be classified into four main categories based on its typical applications.XO - Crystal OscillatorTemperature Compensated Crystal OscillatorThe device has temperature compensation circuit to suppress output frequency deviation caused by surrounding temperature. That is, e.g. the output signal from a temperature sensor (e.g., a thermistor) is used to generate a correction voltage that is applied to a variable reactance (e.g., a varactor) in the crystal network. The reactance variations compensate for the crystal's F vs. T characteristic. Analog TCXO can provide about a 20X improvement over the crystal's F vs. T variation.OCXO - Oven Controlled Crystal OscillatorThe device usually contains an oven block where the temperature sensor, heating element, oven circuitry, ... More About: Categories
What is Temperature Compensated Crystal Oscillators?
2008-04-20 18:38:00 The temperature stability of a basic crystal oscillator can be improved by incorporating in the oscillator circuit components with temperature characteristics approximately equal to and opposite from that of the crystal.Typical Applications:PCS Base StationsLand Mobile RadioCellular TelephonyRadio in the Local LoopFeatures:EFC StandardLow ProfileSmall Size100 % RoHS compliantTemperature compensated crystal oscillators (TXCO) typically employ a thermistor network to generate a correction voltage which reduces the frequency variation over temperature. The correction voltage is usually applied to a varactor diode in the crystal circuit such that the crystal frequency may be varied by a small amount. TCXO stability can approach 0.1 PPM but several problems must be addressed. A TCXO that resides at one temperature extreme for an extended period of time may exhibit a frequency shift when returned to normal room temperature.Usually this hysterisis or "retrace" error is temporary but a seem... More About: Crystal
30W UHF RF Power Amplifier For 440 MHz
2008-04-15 13:30:00 This Power Amplifier application works on UHF band frequency 440 Mhz and uses as UHF repeater power amplifier. Power amplifier out 30 watts (5 dB gain) use a single transistor 2SD1434 For driving the amplifier use 10-14 watt input with output power range 30-45 watts. Please see datasheet sample design for 470 MHz (SD1434.pdf) and Amplifier Application produced by Hamtronics.Other use of the power amplifier is for online covering broadcast (STL). If you use stereo encoder on exciter, so please use down converter with 340 MHz oscillator frequency direct to FM broadcast receiver.
TV Video Modulator With LM2889
2008-04-14 08:39:00 The LM2889 is designed to interface audio and video signals to the antenna terminals of a TV receiver. It consists of a sound subcarrier oscillator and FM modulator, video clamp, and RF oscillators and modulators for two low-VHF channels.The LM2889 allows video information from VTRs, video disk systems, games, test equipment, or similar sources to be displayed on black and white or color TV receivers.Features:* Pin for pin compatible with LM1889 RF section* Low distortion FM sound modulator (less than 1% THD)* Video clamp for AC-coupled video* Low sound oscillator harmonic levels* 10V to 16V supply operation* DC channel switching* Excellent oscillator stability* Low intermodulation productsDownload datasheet - Application Note For Stereo Audio
Video Modulator With PLL Output
2008-04-14 08:32:00 Circuit DescriptionOscillatorThe RF-oscillator is available at pins 3-7. The oscillator operates as a symmetrical Colpitts circuit. The oscillator chip ground, pin 5, should be connected to ground at the resonance circuit shielding point. An external oscillator can be injected inductively or capacitively via pins 3 and 7. The layout of the PCB should be such as to provide a minimum shielding attenuation between the oscillator pins 3-7 and modulator output pins 15-17 of approximately 80 dB.For optimal residual carrier suppression, the symmetrical mixer outputs at pins 15, 17 should be connected to a matched balanced-to-unbalanced broadband transformer, e.g. a Guanella transformer with good phase precision at 0o and 180o. The transmission loss should be less than 3 dB. In addition, an LC-low pass filter combination is required at the output. The cut-off frequency of the low pass filter combination must exceed the maximum operating frequency.Video The video signal with the negative sync...
RF Power Meter 0-500MHz With PIC16F876
2008-04-14 08:27:00 RF Measurement has been an expensive work so far the cost of measuring instruments are concerned. RF Meter is based on PIC16F876 microcontroller, AD8307 and 2x20 LCD display. Frequency range measurement is 0-500 MHz and Full documentation is included.This power meter kit has two push buttons to control the functions. Very cost effective and simple to use. 4 Push buttons used in this kit are right angle type and are sufficiently long enough to come out of the box, if you decide to house this meter in a case.Download Project Domumentation, Schematic, Hex Code, and Visit page More About: Power
PLL TV RF Modulator CXA1929
2008-04-06 14:17:00 Fully synthesized I2C controlled UHF/VHF TV RF Modulator compatible with PAL and NTSC video formats.Features? Minimal adjustment of external components? For use on VHF and UHF TV Frequencies? Video RF carrier frequency programmable in 125kHz steps? ATT Driver? I2C control of:a. Video RF Carrier Frequencyb. Sound Carrier Frequencyc. Modulation Depth (±2.5 % Typ.)d. FM Deviation (±7 % Typ.)e. P/S ratio (±1 dB Typ.)f. Nicam output enable to sleepg. Video RF carrier enable to sleep? On chip Regulator 3.1 V (datasheet)Functional Description of RF Modulator SystemA block diagram of the RF modulator is shown in datasheet The composite video signal passes through an amplitude limiting circuit and a digitally controlled modulation depth adjustment circuit. By means of three allocated I2C control bits it is possible to adjust the modulationdepth from a nominal 74 % to 86% in 2.0 % steps. Modulation depth can also be controlled externally byaddition of an external resistor on pin3. The video s...
CATV amplifier module BGX881
2008-03-30 17:55:00 DescriptionThis CATV amplifier module is a product of Philips Semiconductor, hybrid amplifier module CATV systems operating over frequency range of 40-860 MHz at a voltage supply of 24V DC with features :· Excellent linearity· Extremely low noise· Silicon nitride passivation· Rugged construction· Gold metallization ensures excellent reliability.This CATV Module can be used to amplify your CATV Modulator for 13 dB. And in my technical experiences in tv transmitter it can not only used on cable media, but also it can be used on air via a suitable antenna. With Adding a TV low pass filter you are able to transmit your video for 1 km.CircuitComponentsC1, C3, C4 ceramic multilayer capacitor 1nFC2 ceramic multilayer capacitor 1nF(max)R resistor 200 Ohm 1WPins 1 and 9 carry DC Voltages More About: Amplifier
AV Modulator for UHF Band NJM2259
2008-03-30 16:55:00 The NJM2259 is a RF modulator IC especially designed for UHF band RF modulator and consists of video clamp circuit, white clip circuit, video AM modulator and audio FM modulator, built into one chip. (datasheet)FEATURES :? Operating Voltage 5V? Picture-to-sound ratio is adjustable? Audio ripple is decreased by two internal regulators? Audio input circuit with low shock noise? Carrier-off switch function on chip? Bipolar Technology? Package Outline : DMP16 More About: Band
Horizontal Polarized UHF Panel TV Antenna
2008-03-27 11:46:00 This UHF Panel Antenna designed for broadband TV Transmission Antenna in UHF Band IV and V. For broadband use, try to design adapter 50 Ohm to 260-300 Ohm for mid band frequency of 470-860 MHz. With 50 Ohm Antenna Impedance input that composed from dual single antenna, you need two lines transmssion adapter (Antenna Power Divider) for combining. Combining two single antenna in order to increase antenna intensity (dB)If you want to constuct this panel antenna type, use this reference on images below:Stacking more panels it's possible to obtain customized patterns, increse the gain and the power handling capacity according to your requirements. Datasheet reference.
14 Watts UHF TV RF Amplifier #2
2008-03-22 23:30:00 From #1 UHF TV RF amplifierBIAS CIRCUITComponent Part List:C1, C2, C4, C5, C6 = 1nF LCC Chip + 10nF LCC ChipC3 = 100µF SpragueC7 = 10µF SpragueD1 = 1N 4001L1, L2 = 5 Turns , Diameter 0.5 mm, W Diameter 3mmP1 = 1k.R1 = 56 ohm/ 1/2WR2 = 5600 ohm, 1/2WR3 = 2.2 ohm, 3WR4, R5 = 56 ohm, 1WR6 = 4,7 ohm, 1/2WT1 : BDX 54 B/BD139Previous Page ... More About: Watts , Amplifier
Microwave Power Meter #2
2008-03-22 23:22:00 Some remarksThe input circuit determines the frequency characteristics of the meter. When using Schottky diodes like 1SS99 or HP5082/2800 and a 'microwave' design of the input circuit (C_in: use a smd type, 50 ohm terminator: use 2 smd resistors of 100 Ohm), proper earth etc, a reasonably flat frequency characteristic up to 1.5 GHz is easy to obtain. When the input C (C_in) is reduced to about 20 pF, and BAT14 diodes are used as the detector, proper measurements up to 3.5 GHz (+/- 1 dB) can be obtained. In this case the meter will also detect 10 GHz signals, but the frequency characteristic (above 3.5 GHz) of the input circuit is far from flat, so no real power measurement can be done on these frequencies. As an experiment C_in was reduced to 0.68 pF and the diodes used are BAT14. Power can now be detected over a very large (up to 26 GHz) frequency range; as the frequency characteristic is far from flat, a calibration in mW / uW is not useful.Practical experienceThe electronic cir... More About: Microwave , Meter
Wideband Amplifer 470-860 MHz For TV Transmitter #2
2008-03-22 23:07:00 MECHANICAL MACHINING OF THE HEATSINKThe raised edges at the top side of the heatsink have been removed because the printed circuit board has a width of 113 mm (see Fig.3). To fit the heatsink to the printed-circuit board the following machinings have been carried out:Rectangular holes of 2.8 mm deep have been mould in the heatsink because the transistor leads have to be soldered on the printed-circuit board. Also it was necessary to make avings of 4 mm wide and 0.6 mm deep at the positions of the straps on the printed-circuit board. The transistors have been fastened with M 2.5 screws in the heatsink (see Fig.4). To achieve that the printed-circuit board lays tight to the heatsink also savings have been made in the heatsink on the spots of the 8 rivets through the printed-circuit board. For fastening the printed-circuit board on the heatsink on 7 places, holes with M 3 screwthread have been made in the top side of the heatsink, corresponding with indicated holes in the printed-circu... More About: Wideband , Transmitter
Microwave Homemade Outdoor Antenna 2.4 GHz #2
More articles from this author:2008-03-22 22:53:00 If the inner wire is made from rod it is good idea to drill axially a 3 mm hole on the end of it so the rod can be solder firmly to the inner tap of the N connector. The length of the rod becomes about L/4, but it is better first to leave it longer and cut it later after the parts are first pre-assembled.The copper conduit must be split with a metal saw as accurately as possible and deburred with a file. The end of the split conduit is then fastened to the centre of the pan. It is not possible to solder it directly to aluminium but we made a flange from tinned steel sheet to same dimensions as the flange of the N connector. In the middle of the flange is drilled a hole equal the outer dia of the conduit and four 3.5 mm holes as in the N connector. The one end of the split conduit is then soldered in the centre hole of the flange while keeping the width of the slots between halves to 1-1.5 mm.The split conduit is then cut so that the length of the open slots becomes a very accurate L... More About: Antenna , Outdoor , Microwave 1, 2, 3, 4 |
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