Toshiba's new technology cuts phase noise in oscillation ICs for wireless communication

Jun 16, 2011

Toshiba Corporation today announced that it has developed noise reduction technology that reduces jitter in radio-frequency signals, cutting phase noise by up to 90 percent. This breakthrough opens the way for a further migration to high-speed wireless communication chips for wireless LAN and WiMAX.

Radio frequency phased locked loops (PLL) in LSI chips were typically structured with analog and digital circuits. As achieving ultra-fine is highly challenging, there is now a shift to all digital PLL using time-to-digital converters (TDC). While digitization reduces circuit size it also increases phase noise -- a degrading displacement in the pulse of a radio frequency signal -- due to larger delay in the TDC’s inverter circuits. Cutting phase noise is essential for high speed communication standards, like WiMAX, which require highly accurate signals. There is the concern that current TDC is sensitive to variations in manufacturing processes that impact on their performance. This raises a need for more robust manufacturability.

To reduce susceptibility variations in mass production and suppress phase noise, Toshiba developed a new TDC integrating interpolation circuits that use a low resistance conductor to connect the output of two inverters. A triple interpolation splits the cycle of output signal of frequency synthesizers, and reduces phase noise by 90 percent. This solution successfully achieves a PLL with stable performance, as it utilizes a stable waveform from the PLL itself as a reference time interval for converting time to digital data, not the delay time of the inverters. In a test chip manufactured with 65nm CMOS process, phase noise was reduced to -104dBc/Hz, 90 percent lower than that of the previous all digital PLL that Toshiba announced at ISSCC2011. Chip size was cut to 0.18 mm2, approximately 80 percent smaller than the analog PLL in a mobile transceiver chip that Toshiba announced at ISSCC2010.

 This achievement will be announced on June 16 at the 2011 VLSI Symposium now being held in Kyoto, Japan.

Explore further: A bump circuit with flexible tuning ability that uses 500 times less power

Provided by Toshiba Corporation

5 /5 (2 votes)
add to favorites email to friend print save as pdf

Related Stories

Recommended for you

The ethics of driverless cars

6 minutes ago

Jason Millar, a PhD Candidate in the Department of Philosophy, spends a lot of time thinking about driverless cars. Though you aren't likely to be able to buy them for 10 years, he says there are a number ...

We need new laws to govern cyberwarfare

26 minutes ago

President Bush is reported to have said: "When I take action, I'm not going to fire a US$2m missile at a US$10 empty tent and hit a camel in the butt. It's going to be decisive." As the quote suggests, when ...

Ticketfly buying WillCall for on-premise data

1 hour ago

Ticketfly Inc., a San Francisco-based technology company among several posing a challenge to Ticketmaster, is acquiring WillCall Inc., a crosstown rival that turns your smartphone into a mobile wallet at live events.

Voice, image give clues in hunt for Foley's killer

2 hours ago

Police and intelligence services are using image analysis and voice-recognition software, studying social media postings and seeking human tips as they scramble to identify the militant recorded on a video ...

Smartphone-loss anxiety disorder

2 hours ago

The smart phone has changed our behavior, sometimes for the better as we are now able to connect and engage with many more people than ever before, sometimes for the worse in that we may have become over-reliant on the connectivity ...

User comments : 0