AMP - Definition of Ultra-wideband device

[Paul Withington <paul.withington@tdsi.com>]

Ian:

As we discussed on the telephone, the consensus of the working group when it
was gathered in Palo Alto was that the fractional bandwidth definition would
apply independent of the band of operation. The concept was that the
qualities achieved by using a waveform with a small number of cycles (or
effectively a small number of cycles) would be lost if UWB were defined as
MA-Com proposes.

Two others have floated alternative definitions. Greg Shreve of TRW proposed
a similar definition where after a point the fractional bandwidth would be a
value between 2% and 10%. Tom Holden of Trimble proposed a formula that had
a declining fractional bandwidth with increasing frequency.

We here at Time Domain think that the fractional bandwidth definition is the
most logical and that, if anything, we should debate the value of the
fraction. As was noted in the DARPA report, the 25% is somewhat arbitrary.
It represents, so they said, where conventional RF techniques break down
(e.g., device linearity constraints and steady-state modeling vs. transient
modeling). Thus, new approaches were necessary.

Time Domain will stick with the 25% definition at this time.

Paul Withington

		-----Original Message-----
From:	Gifford, Ian C. [mailto:giffordi@amp.com]
Sent:	Tuesday, December 01, 1998 4:08 PM
To:	'Paul Withington'
Subject:	AMP - Definition of Ultra-wideband device

Paul,

Per our discussion it is our (M/A-COM, a division of AMP, Inc.) intention to
submit the following UWB Device definition along with our Comments to the
FCC's ET Docket 98-153, NOI:

<snip>
Definition of Ultra-wideband device

M/A-COM proposes that the FCC adopt the following definition for an
Ultra-wideband signal:

Ultra wide-band signal.  An ultra wide-band signal is an intentionally
radiated signal designed to have a bandwidth to be equal to at least 25% of
the fractional bandwidth below 10 GHz carrier frequency, and at least 2.5
GHz above 10 GHz carrier frequency.

The term "fractional bandwidth" should be defined in the Commission's Rules
as follows:

Fractional bandwidth.  The bandwidth defined by the expression 2(fH  - fL) /
(fH + fL) in which fH  is defined as the highest frequency limit and fL is
defined as the lowest frequency limit, which mark the frequencies that are
20 dB below the maximum of the power spectral density envelope.  As a
general principle, Ultra-wideband devices should be regulated under Part 15
of the Commission's Rules on an unlicensed basis. 
<snip>

Please advise, if necessary, if there is any language that is problematic to
the Ultra-wideband Working Group and/or Time Domain Corporation.

Sincerely,

Ian
	
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Ian Gifford, AMP - M/A-COM Div
1011 Pawtucket Boulevard
M/S-106
Lowell, MA 01853 USA +1 978 442-4650V, -5442F,
giffordi@amp.com
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