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AUDI O & VIDEO PROCESING The WiSA standard also offers a solution to the problem of running cables from all of the sources to an active soundbar. Instead a small audio “hub” can be used to select inputs, decode the surround sound formats, and then use WiSA standard to send the 7.1 audio wirelessly to all speakers. Or the WiSA transmitter can be built into the TV itself, and the 60’s table radio-sounding flat-screen speakers avoided in the first place. Of course wireless speakers require AC power to operate, but that is usually not a problem. Also schemes using rechargeable surround speakers, which need less total energy in most cases, can be considered. The combination of efficient class D amplifiers, wireless audio sources such as Bluetooth, and uncompressed Fig. 2: Screen capture of the filter setup for the TAS5727 amplifiers. high quality wireless audio transport systems such as WiSA offer an opportunity for audio electronic manufacturers to create better sounding systems with less installation headaches than available just a few years ago. Figure 1 illustrates the major components of a typical active soundbar. Due to space constraints in a soundbar the major functions are usually split across multiple circuit board assemblies. The I2S standard for audio is used to send multichannel audio data between sections. To meet the 0.5W standby energy consumption targets and be able to turn the unit on with an IR remote, a small microprocessor is typically used, allowing the main SoC to enter deep sleep mode. Electronic crossovers are implemented for the speakers, which consist of woofers and tweeters for the Left, Center, and Right channels. Figure 2 shows a screen capture of the filter setup from the design tool for the TAS5727 amplifier ICs, which were also used to provide electronic crossover and driver correction in the prototype system described in the article. This easy to use interface, typical of these types of parts, makes it easy to enhance the driver sound quality much more easily than could be done with passive crossovers in a traditional speaker design. From entry level to high performance. Oscilloscopes from the T&M expert. Fast operation, easy to use, precise measurements – that’s Rohde & Schwarz oscilloscopes. ¸RTO: high performance (Bandwidths: 600 MHz to 4 GHz) ¸RTM: upper midrange (Bandwidths: 350 MHz and 500 MHz) HMO3000: midrange (Bandwidths: 300 MHz to 500 MHz) HMO: entry level (Bandwidths: 70 MHz to 200 MHz) All Rohde & Schwarz oscilloscopes incorporate time domain, logic, protocol and frequency analysis in a single device. Take the dive at www.scope-of-the-art.com/ad/all


EETE FEB 2014
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