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Application Notes

AN-1283: Receiving the 4:2:0 Stream with the ADV7619

This 2-page Application Note outlines the usage of the ADV7619 HDMI® video receiver for the 4:2:0 HDMI stream 4k × 2k at 60 Hz. The ADV7619 can receive 4:2:0 video streams in the same way it receives 4:4:4 data in 4k × 2k modes. To enable this, set OP_FORMAT_SEL to the value of 0x54 and set all other I2C writes in the same way as for 4k × 2k 4:4:4 video mode. Because the ADV7619 works only as a bypass for 4k × 2k modes, it outputs samples as they are received without providing color space conversion (CSC). The receiver bypasses CP core and thus neither CSC nor up-conversion/down-conversion of video standard is available.

AN-1277: Utilizing the Cyclic Redundancy Check Block of the ADV7850

The ADV7850, the first complete audio/video front-end device developed by Analog Devices, targets the professional and consumer video markets. The device incorporates a frame checker block that employs cyclic redundancy checking (CRC). This 3-page Application Note outlines the background of the frame checker function and details how it is utilized.

AN-1270: ADV7511/ADV7511W/ADV7513 Based Video Generators

This 8-page Application Note shows a basic configuration in which a field-programmable gate array (FPGA) is used as a signal source, producing sync timing and a video pattern, and the ADV7511/ADV7511W/ADV7513 are configured to output a valid High-Definition Multimedia Interface (HDMI®) or digital visual interface (DVI) stream—focusing on the most basic example to illustrate ways of generating a valid video stream.

AN-1260: Crystal Design Considerations for Video Decoders, HDMI Receivers, and Transceivers

This 3-page Application Note helps designers to achieve frequency stability and accuracy for the external oscillators used with video decoders, which typically require a 28.63636-MHz crystal with 50-ppm frequency stability in fundamental mode.

AN-1256: Manual Scaling in the ADV7186

This 4-page Application Note describes the automatic and manual scaling algorithms used in the ADV7186 video decoder. Upscaling changes a low resolution video input to a higher resolution video output; downscaling changes a high resolution video input to a lower resolution video output to satisfy the back end device without the need for external memory.

AN-1249: Converting 3D Images to 2D Images Using the ADV8003 Evaluation Boards

The ADV8003 video signal processor with TTL logic and serial video inputs can de-interlace and scale input video. It generates and blends a bitmap-based on-screen display and provides the blended video to one or more output. Other available outputs include two HDMI transmitters, a six-DAC encoder with SD and HD support, and a TTL output. This application note describes how to pass 3D video through the ADV8003 and convert the 3D image to a 2D image.

Circuits from the Lab

CN0296: Low Cost, High Performance Sound Bar System

This low-cost, high-performance sound bar system can accept an analog stereo audio signal as an input and output up to eight channels of audio with discrete processing on each channel. The circuit offers low power consumption and high efficiency without sacrificing audio quality, making it ideal for small docking stations and portable media devices. The circuit is capable of driving headphones without the need of additional components. The ADAU1761 low power, stereo audio codec with integrated SigmaDSP® digital audio processing accepts two audio channels. It is optimized for audio applications and programmed using SigmaStudio development software for ease of use and faster development. The output of the ADAU1761 can send up to eight channels of digital audio data to the output amplifiers using the serial interface. The ADAU1761 allows different audio signal processing in each channel, such as volume control, custom equalization, filtering, and spatialization effects tuned to the specific speaker configuration. The ADAU1761 processes and converts analog audio to digital format and drives the SSM2518 power amplifier. The SSM2518 is a digital input class-D audio power amplifier that can output two channels of audio with a continuous power of 2 watts each into a 4 Ω load. The channel-mapping feature of the SSM2518 allows it to select the specific channel to output among those that are available in the interface, making it ideal for surround sound applications.

CN0284: High-Performance, Low-Noise Studio Microphone with MEMS Microphones, Analog Beamforming, and Power Management

This professional-grade studio or live-performance microphone uses up to 32 analog MEMS microphones connected to op amps and a difference amplifier. Designed for low noise, its output is linear for acoustic inputs up to 131 dB SPL. Powered from a single 9-V battery, the ±9-V and 1.8-V power rails are generated from two voltage regulators. The ADMP411, which consists of a MEMS microphone element and an impedance-matching amplifier, has a frequency response that is flat to 28 Hz, making it ideal for full-bandwidth, wide dynamic range audio capture.

USB Powered DVI/HDMI-to-VGA Converter (HDMI2VGA) with Audio Extraction (CN0282)

This circuit provides a complete solution for converting HDMI/DVI to VGA (HDMI2VGA) with an analog audio output. Using the low-power ADV7611 HDMI receiver, it is capable of receiving video streams up to 165 MHz. Powered from a USB cable, it works for resolutions up to 1600 × 1200 at 60 Hz. The circuit uses EDID content to ensure that the video stream from the HDMI/ DVI source is at the highest possible resolution supported by the HDMI source, converter, and VGA display.

Low Noise Analog MEMS Microphone and Preamp with Compression and Noise Gating (CN0262)

This circuit interfaces an analog MEMS microphone to a microphone preamp. The ADMP504 consists of a MEMS microphone element and an output amplifier. Analog Devices’ MEMS microphones have a high signal-to-noise ratio (SNR) and a flat wideband frequency response, making them an excellent choice for high-performance, low-power applications. The SSM2167 low-voltage, low-noise mono microphone preamp is a good choice for use in low-power audio signal chains. This preamp includes built-in compression and noise gating, which gives it an advantage for this function over using just an op amp in the preamp circuit. Compressing the dynamic range of the microphone signal can reduce the peak signal levels and add additional gain to low level signals. Noise gating attenuates the level of signals below a certain threshold, so that only desired signals, such as speech, are amplified, and noise in the output signal is reduced. These features help to improve the intelligibility of the voice signal picked up by the microphone.

New Product Briefs

March 2014

High-performance 12-channel, 24-bit, 192-kHz Differential-Output DACs

adau1962The ADAU1962 high-performance digital audio circuit comprises 12 multibit Σ-Δ DACs with differential outputs, plus digital filters and volume controls. The DACs provide 118-dB dynamic range and –98-dB total harmonic distortion plus noise (THD+N). A microcontroller can adjust volume and other parameters, and read the temperature of the on-chip temperature sensor, via an SPI/I2C port. For low EMI, the on-chip PLL derives the master clock from an external left/right frame clock—eliminating the need for a separate high-frequency master clock and allowing the DACs to be used with or without a bit clock. The continuous-time architecture and low-voltage operation combine to further minimize EMI, power consumption, and digital waveform amplitudes. The ADAU1962 uses two separate power sources or a single analog supply with an on-chip regulator producing the digital supply. Operating with a 4.5-V to 5.5-V analog supply, 2.25-V to 3.6-V digital supply, and a 3.0-V to 5.5-V logic supply, it consume 421 mW in normal mode and 15 µW in power-down mode. Available in an 80-lead LQFP package, it is specified from –40°C to +105°C, release to automotive (RTA) qualified, and priced at $5.52 in 1000s.

February 2014

SigmaDSP Audio Processor

adau1452The ADAU1452 SigmaDSP® audio processor far exceeds the digital signal processing capabilities of earlier devices. Audio processing algorithms are realized in sample-by-sample and block- by-block paradigms that can be executed simultaneously in a signal processing flow created using the SigmaStudio™ graphical programming tool. The 32‑bit DSP core clocks at up to 294.912 MHz, executing up to 6144 instructions per sample at 48 kHz. The integer-N PLL and flexible clock can generate up to 15 audio sample rates simultaneously. The clock generators, asynchronous sample rate converters, and flexible audio routing matrix make an audio hub that greatly simplifies the design of complex multirate audio systems. Configurable serial ports, S/PDIF interfaces, and multipurpose I/O pins allow interfacing with a wide range of ADCs, DACs, digital audio devices, amplifiers, and control circuitry, and integrated decimation filters enable a direct interface with PDM-output MEMS microphones. Programming and configuration are handled via I2C/SPI control ports, and self-boot functionality enables standalone systems. Operating on 1.2-V digital, 3.3-V analog, and 1.71-V to 3.63-V I/O supplies, the ADAU1452 dissipates 2 W at 3.3 V and 380 mW in power-down mode. Available in a 72‑lead LFCSP package, the automotive-qualified device is specified from –40°C to +105°C and priced at $11.99 in 1000s.

High-performance HDMI Crosspoint Transceivers with on-screen display

adv7625The ADV7625 and ADV7626 high-performance high-definition multimedia interface (HDMI®) transceivers with crosspoint and splitter capabilities support UHD (4K) video. They include two HDMI receivers, two HDMI transmitters, two audio output ports, and two audio input ports. The ADV7625 also includes five HDMI input ports, a 5 × 2 crosspoint multiplexer, and a pixel port input; and the ADV7626 includes two HDMI input ports and a 2 × 2 crosspoint multiplexer. Both devices support all HDCP repeater functions through ADI’s fully tested repeater software libraries and drivers. The receivers and transmitters support video formats up to 4k × 2k at 24/25/30 Hz, all mandatory HDMI 3D TV formats, and THX® Media Director™. Each receiver includes an equalizer that ensures robust operation with cables up to 30 meters. They share a 768-byte volatile extended display identification data (EDID) memory, which can facilitate one or two EDIDs. Each HDMI port features dedicated 5-V detect and Hot Plug™ assert pins. Each transmitter supports audio return channel (ARC) and features an integrated HDMI CEC controller that supports capability discovery and control (CDC). Each audio port supports extraction and insertion of up to eight channels of I2S audio data and S/PDIF, direct stream digital (DSD), and high bit rate (HBR) audio. The pixel port facilitates reception of digital video data from an analog front-end decoder such as the ADV7180, ADV7181D, or ADV7842. An integrated on-screen display (OSD) generator enables creation and control of high-quality character- and icon-based status and control displays. The OSD can be programmed using Blimp, ADI’s OSD development tool, and can be overlaid on UHD video. The ADV7625 and ADV7626 operate on 1.8-V and 3.3-V supplies. Available in 260-ball CSP-BGA packages, they are specified from 0°C to +70°C and priced at $16.20/$14.07 in 1000s.

High-performance HDMI Transceiver with on-screen display

adv7627The ADV7627 high-performance high-definition multimedia interface (HDMI®) transceiver supports UHD (4K) video. It includes five HDMI inputs, one HDMI output, an audio output port, an audio input port, and a pixel port input. The device supports all HDCP repeater functions through ADI’s fully tested repeater software libraries and drivers. The receiver and transmitter support video formats up to 4k × 2k at 24/25/30 Hz, all mandatory HDMI 3D TV formats, and THX® Media Director™. The receiver includes an equalizer that ensures robust operation with cables up to 30 meters, and a 768-byte volatile extended display identification data (EDID) memory, which can facilitate one or two EDIDs. Each HDMI port features dedicated 5-V detect and Hot Plug™ assert pins. The transmitter supports audio return channel (ARC) and features an integrated HDMI CEC controller that supports capability discovery and control (CDC). The audio ports support extraction and insertion of up to eight channels of I2S audio data and S/PDIF, direct stream digital (DSD), and high bit rate (HBR) audio. The pixel port facilitates reception of digital video from an analog front-end decoder such as the ADV7180, ADV7181D, or ADV7842. An integrated on-screen display (OSD) generator enables creation and control of high-quality character- and icon-based status and control displays. The OSD can be programmed using Blimp, ADI’s OSD development tool, and overlaid on 4K video The ADV7627 operates on 1.8-V and 3.3-V supplies. Available in a 260-ball CSP-BGA package, it is specified from 0°C to +70°C and priced at $10.66 in 1000s.

Technical Articles

Witold Kaczurba, FPGA-Based System Combines Two Video Streams to Provide 3D Video, Analog Dialogue, 2013-12-02

Michael Corrigan & Joe Triggs, CRC testing in video applications, EDN, 2013-09-10

Jeff Ugalde, Ian Beavers, and Lie Dou, Deliver Quad-HD Video Over HDMI Cables, Electronic Design, 2013-03-05

Witold Kaczurba and Brett Li, HDMI Made Easy: HDMI-to-VGA and VGA-to-HDMI Converters, Analog Dialogue, 2013-02-04

Jerad Lewis and Paul Schreier, Low self noise: The first step to high-performance MEMS microphone applications, EE Times, 2012-11-28

Brett Li and Li Dou, HDMI I/O Solution and Reference Design, Global Electronics China, 2012-09-19

Jerad Lewis, Understanding Microphone Sensitivity, Analog Dialogue, 2012-05-01

Javier Calpe, Italo Medina, Alberto Carbajo, and María José Martínez, AD7879 Controller Enables Gesture Recognition on Resistive Touch Screens, Frontier Journal, 2012-05-01

Webinars and Tutorials

What is a "Wide Dynamic Range" Microphone and why does it matter to my design? - MEMS microphones with the capability to capture very high sound pressure acoustic waves (loud noises) with high fidelity hold the potential to improve user experience in audio capture and to make acoustic detection viable for a range of applications that might have previously been unsuitable for such methods. We'll discuss design considerations for these microphones and applications that might benefit from such high performance.

 

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