Simplified High Frequency Broadband Tuner
Tech ID: 03-95-37
A novel tuning and demodulation scheme utilizing analog coarse tuning and
digital fine tuning is presented.
Background:
Standard practice in radio frequency receiver design has been to convert high
frequency signals to one or more intermediate frequencies which, in a final
translation step, are converted to baseband (direct current, DC). This is
undesirable due to the complexity of needing a mixer and image rejection filter
at each translation stage.
Each mixing operation produces both the desired signal and an image signal
which must be filtered out. For these reasons, it would be desirable to have a
receiver that allows a direct conversion of a radio frequency signal to baseband.
However, no practical methodology exists for this as: 1) direct current is
difficult to amplify and is often dominated by 1/f noise; 2) significant DC
signal errors can arise from the mixers and amplifiers; and 3) the necessary
lowpass filters are difficult and expensive to make in order to fulfill the
conflicting requirement for a sharply defined frequency response and minimal
phase distortion of the signal.
Advantages:
By combining direct conversion to baseband with novel tuning and signal
processing schemes the invention achieves advantages such as, elimination of the
intermediate signals and attendant processing; simplification of processing the
near direct current signal due to the use of a novel digital signal processing (DSP)
technique; a wider tuning range than is available in superheterodyne receivers;
use of the novel signal processing scheme allows the use of inexpensive and
readily made analog filters; design requirements for the phase locked loop (PLL)
are simplified due to a novel tuning technique which is made possible by the
novel signal processing scheme; no adjustable or high-precision tuning circuits
are required.
Issued
Patents
For additional information, please contact:
John D. Reagh
Manager, Business Development & Legal Affairs
Washington Research Foundation
2815 Eastlake Avenue E, Suite 300
Seattle, WA 98102
Tel: 206.336.5600
Fax: 206.336.5615
|
