(i) Explain the working of MP3 player. (ii) Give troubleshooting procedure for audio systems.
1 Answer
Answer :
(i) Block diagram of MP3 Player
Explanation:
Audio
Our digital audio amplifier family is built to simplify audio architecture by lowering the system cost and enabling easy interfacing. Using a digital interface eliminates the need for a D/A converter in the host processor, and the PDM or I2S format guarantees an ultra small IC footprint. The digital interface assures low RF susceptibility in the device and the total system, and low sensitivity to input clock jitter. In addition, the digital interface eliminates the need for couple capacitors and safeguard speakers by eliminating problems coming from DC offsets due to leakage currents of an analog design.
(ii)Charger interface
Whether your device is charged via the USB port or a separate charger, it is exposed to incorrect polarity or abnormally high voltages. Any of these two occurrences poses a threat to the charger circuit and the PMU of the mobile device. In addition, the USB/charger port can be subject to ESD strikes and other transient discharges.
NXP offers an application specific portfolio of TVS diodes and ESD arrays, which enable cost efficient protection solutions - ESD, reverse polarity, overvoltage, other transient discharges – with the smallest footprint.
(iii)Memory Card Interfaces
According the IEC61000-4-2 standard, SD host interfaces require additional highlevel ESD protection, in addition to the integrated ESD protection which is typically very weak. They also support EMI filtering, integrated biasing resistor networks, regulated power supply to supply SD-memory cards directly from a battery, and voltage level translation to enable the use of low-voltage host processors to communicate with 2.7 V to 3.6 V compliant SD-memory card devices
(ii) Give troubleshooting procedure for audio systems. * Shut down and restart the system. Surprisingly often, this solves the problem. * Verify that all cables are connected, that the speakers have power and are switched on, that the volume control is set to an audible level, that you haven't muted audio in Windows, and so on. * Determine the scope of the problem. If the problem occurs with only one program, visit the web sites for Microsoft, the software company, and the audio adapter maker to determine if there is a known problem with that program and audio adapter combination. If the problem occurs globally, continue with the following steps. * Verify that the audio adapter is selected as the default playback device. If you have more than one audio adapter installed, verify that the default playback device is the audio adapter to which the speakers are connected. * If your audio adapter includes a testing utility, run it to verify that all components of the audio adapter are operating properly. * If you have another set of speakers and /or a spare audio cable, substitute them temporarily to eliminate the speakers as a possible cause. If you have a set of headphones, connect them directly to Line-out on the audio adapter to isolate the problem to the system itself. Alternatively, connect the questionable speakers to another system with a known good audio adapter, or even an MP3 player or portable CD player.