IEEE Solid-State Circuits Magazine - Winter 2016 - 17

University in Ottawa, Canada, he was
motivated to shift his research to
semiconductors; first to charge-coupled devices (CCDs) and later metal-
oxide semiconductor (MOS) analog
signal processing electronics. Prof.
Copeland nurtured links between the
university and local industry, which
in the Ottawa region focused primarily on communications and microelectronics. He began consulting with the
Northern Electric R&D Laboratories on
industry-related problems. The forced
sale by AT&T of its non-U.S. subsidiaries precipitated the creation of Northern Telecom in Canada (shortened
later to Nortel), a new company eager
to develop its own innovative products. Miles was perfectly positioned to
grow as an academic and researcher
along with the new company, a situation that repeated itself too many time
across his career to be serendipity.

deliver (1978 onward) a complete line
of fully digital telecommunications
products. Its initial codec designs
using CCD filters suffered from poor
performance. Switched-capacitor techniques offered higher performance
and greater levels of integration and
were therefore adopted very quickly. A
highly integrated subscriber line interface for digital switching products
using switched-capacitor filters was in
full production at Nortel by 1981. The
success of Nortel's computer-driven
voice and data-switching products propelled the company's growth well into
the 1990s, and the switched capacitor
was a key enabling technology. Ultimately, the shift from mechanically

graduation, Dr. Ribner applied this
work at General Electric and Analog
Devices in products such as oversampled analog-to-digital converters
(ADCs) and delta-sigma modulators.
Ribner recalls his association with
Prof. Copeland in his article in this
issue, "Miles A. Copeland: Remembrances from a Former Student and
Longtime Friend."
Carleton Ph.D. student Kadaba
Lakshmikumar was linked by Prof.
Copeland to Nortel's silicon technology group with the support of manager R.A. (Bob) Hadaway. Kumar's
thesis made use of Nortel's semiconductor technology to model
mismatches in MOS transistors, a

Prof. Miles Copeland is as much a maestro-
an artist of consummate skill-as he is
a master engineer of solid-state circuits.

The Early Years
The first documented use of
switched-capacitor filtering commercially was developed in collaboration with Bell-Northern Research
(BNR), the R&D division of Northern
Telecom. The CCD transversal filters
for anti-aliasing in a monolithic filter
codec (which is used to digitize and
reconstruct analog voice on a telephone line) developed by Miles and
his industry colleagues proved inadequate due to poor signal-to-noise
performance. Miles conceived the
switched-capacitor resistor solution,
and he and Carleton Ph.D. student
Choudhury Rahim demonstrated the
switched-capacitor alternative in collaboration with Terry Caves of BNR
in 1977. Terry recalls his association
with Prof. Copeland and the development of the world's first CCD and
switched-cap filter-codec chips in
his article in this issue, "Miles Copeland's Switched Capacitor: An Invention that Enabled a Revolution in
Digital Communications at Nortel."
The switched-capacitor invention
had a dramatic economic impact on
the fortunes of Northern Telecom. Nortel was the first in the telecommunications industry to announce (1976) and

switched to fully electronic networks
under software control helped transform modern life, from commerce
and banking to personal communication and entertainment. David Lynch
and Robert Hadaway dive deeper into
Miles Copeland's contributions from
an industry perspective in their article
in this issue, "Miles Copeland: Three
Decades of Scientific Excellence and
Industrial Relevance."

Building on Success
Following the initial demonstration of the switched-capacitor filter
codec, follow-up work on switchedcapacitor circuits was done at Carleton University, including the work
of Ph.D. student David Ribner. His
studies included exploration of circuit design techniques and computeraided design for higher frequencies
of operation, differential switchedcapacitor circuits, and related
operational amplifier designs. The
expertise, knowledge, and innovations in precision analog MOS circuits
developed by Prof. Copeland and his
research team enabled mixed-signal
interfaces on silicon for many important commercial applications. After

study that was critical to improving
the performance of circuits such as
ADCs [and digital-to-analog converters (DACs)] and switched-capacitor
filters. MOS capacitors were not characterized carefully for digital circuit
applications, so their susceptibility to processing and lithographic
variations was unknown at the
time. Publication of Lakshmikumar's
work supported the development of
higher resolution monolithic ADCs
and DACs by BNR/Nortel and has
resulted in hundreds of citations in
the literature. Lakshmikumar elaborates on his experience with Prof.
Copeland in his article, "Modeling
Device Mismatch: Miles Copeland's
Vision," also in this issue.

Later Years
Much of the work in Prof. Copeland's group late in his career was
funded by the Telecommunications Research Institute of Ontario
(TRIO). By the end of the 1990s, the
Carleton students working under
Prof. Copeland's leadership developed and published a number of
innovations, including fractionalN frequency synthesis based on

IEEE SOLID-STATE CIRCUITS MAGAZINE

W I N T E R 2 0 16

Table of Contents for the Digital Edition of IEEE Solid-State Circuits Magazine - Winter 2016