Product category:
Communications ICs (Wireless)
News Release from: Analog Devices | Subject: AD9874 MxFE
Edited by the Electronicstalk Editorial
Team on 09 January 2002
Chip integrates IF to digital for
critical radio
Analog Devices has a new IF digitising IC designed for radios that must meet the highest standards of reliability and performance.
Analog Devices has a new IF digitising IC designed for radios that must meet the highest standards of reliability and performance Private mobile radios used by police, fire and ambulance services, as well as narrowband communications systems for fleet management of taxis and delivery services, rely on radio receivers that can detect weak signals in the presence of large interference
This article was originally published on Electronicstalk on 14 Sep 2001 at 8.00am (UK)
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The new AD9874 integrates the IF-to-digital conversion process onto a single chip that can be used to design a highly sensitive, very low-power receiver suitable for a range of equipment, including dispatcher base stations, handheld portable radios and in-vehicle consoles.
The AD9874 is a member of the company's Mixed-Signal Front End (MxFE) family, and is based on ADI's "smart partitioning" methodology - a mixed-signal design technique that partitions the signal path according to performance-enhancing, rather than analogue/digital, boundaries.
The AD9874 MxFE integrates all the functional blocks (excluding the LO and VCO) needed for IF-to-digital conversion in a narrowband superheterodyne receiver.
This partitioning reduces IF filtering, enhances demodulation accuracy and delegates all modulation-specific functions to an external digital signal processor.
The AD9874 MxFE digitises low level IF signals from 10 to 300MHz with a bandwidth of up to 270kHz.
Typical noise figure is 8.7dB SSB NF and linearity, as measured by third-order input intercept point (IIP3), is +0dBm IIP3 (typical maximum bias).
The AD9874 is notable for its power efficiency, 21.2mA rather than 45mA for previous generations.
The signal chain consists of a low noise amplifier, a mixer, a bandpass sigma-delta analogue-to-digital convertor, filters and automatic gain control (AGC) circuitry capable of 12 dB continuous gain adjustment.
The high dynamic range and inherent anti-aliasing provided by the bandpass sigma-delta convertor allow the AD9874 to cope with blocking signals 80 dB stronger than the desired signal.
The AD9874 is fully programmable, providing register-based digital control of AGC and filter parameters, amplifier gain and bias currents through a serial peripheral interface (SPI) port.
The AD9874 is sampling in a 48-lead LQFP (leaded quad flat package).
Priced at $19.95 per unit in 1000-unit quantities, the AD9874 will be available in July 2002.
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