february 2010
 
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Current transformers for electronic energy meters

1.3W, Filterless, Stereo Class D Audio Power Amplifier

Electronic watthour meters have gradually been replacing the electromechanical Ferraris meters in industry for some years. The excellent soft magnetic properties of the VAC core material for DC-tolerant CTs leads to a negligible small amplitude error as well as to an extremely low and linear temperature dependence. Due to the low permeability, a phase error of typically 4° to 5° occurs which is easy to compensate on account of its high constancy of typically± 0.05°.

The compensation can be made digitally by appropriate correction in the microprocessor and analogously by an RC low-pass in front of the input of the A/D converter. A number of major metering chip providers supply tailored solutions for optimum performance and accuracy in combination with these CT types. Their area of application covers a wide range from local individual devices through pre-payment meters right up to (supra)regional networked remote control and readout systems.

Read more at ... Vacuumschmelze

The MAX9701 stereo Class D audio power amplifier provides Class AB amplifier audio performance with the benefits of Class D efficiency, eliminating the need for a heatsink while extending battery life. The MAX9701 delivers up to 1.3W per channel into an 8O load while offering 87% efficiency. Maxim's next-generation, low-EMI modulation scheme allows the amplifier to operate without an external LC filter while still meeting FCC EMI emission levels.

The MAX9701 offers two modulation schemes: a fixed-frequency (FFM) mode, and a spread-spectrum (SSM) mode that reduces EMI-radiated emissions. The MAX9701 oscillator can be synchronized to an external clock through the SYNC input, allowing synchronization of multiple Maxim Class D amplifiers. The sync output (SYNC_OUT) can be used for a master-slave application where more channels are required. The MAX9701 features a fully differential architecture, a full bridge-tied load (BTL) output, and comprehensive click-and-pop suppression.

Read more at ... Maxim









RFID Ticket Printer for OEM Integration

Add plug-and-go WIRELESS to
remote monitoring & rural internet application

KPM400 prints on ticket width from 50 to 120mm (printing area max 104mm with 200 dpi head), with paper thickness from 70 to 350g/m2. KPM400 is a thermal ticket printer, very fast 250mm/sec that prints at high resolution full graphic and text. It's available with new guide adjustment, paper roll or fan-fold. 1D and 2D barcodes printing: UPC-A, UPC-E, EAN13, EAN8, CODE39, ITF, CODABAR, CODE93, CODE128, CODE32, PDF417, DATAMATRIX, AZTEC, QR CODE

KPM400 has Ethernet interface with integrated web server that allows remote monitoring for complete diagnostics in real time of the printer's status.

Thanks to the integrated client mailing, KPM400 is able to automatically send an e-mail to inform you of a possible failure or end of paper. It is also possible to install applications, updates and configurations in real time through the web!

Read more at ... Custom

GSM1308 is a certified quad-band integrated platform that enables simple integration through a serial or USB connection. Available with GSM/GPRS and EDGE capabilities, the GSM1308 also lets you address multiple markets and geographies with a single design. The included modem-management software supports Windows® XP, Professional 2000 and 98SE on select models.

The GSM1308 can be used as a stand-alone serial device with other vertical applications. Enfora’s GSM/GPRS SA-G+ provides maximum versatility in a single affordable device with 2 User Definable Inputs/Outputs (I/O) and 1 user definable output.

The GSM/GPRS GSM1308 modem can utilise input power ranging from 6 VDC to 40 VDC. The device operates operates at the 850/900/1800 and 1900 Mhz frequency bands.

Read more at ... Enfora

 

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