Frequency Agile Signal Processing in Direct Conversion Software Radio

Author(s):  
O. Panfilov ◽  
R. Hickling ◽  
T. Turgeon
2016 ◽  
Vol 5 (3) ◽  
pp. 50 ◽  
Author(s):  
M. Shah ◽  
S. Gupta

Direct Conversion Receiver is the choice of the today’s designer for low power compact wireless receiver. DCR is attractive due to low power, small size and highly monolithic integratable structure, but distortions affect its performance.  I/Q mismatch is the one of the major distortion which is responsible for performance degradation.  In this paper, a novel method for Direct Conversion Receiver is suggested, which makes it insensitive to the I/Q mismatch. Here the classical homodyne architecture is modified to nullify effect of I/Q mismatch. The proposed method can be implemented in the Digital Signal Processing (DSP) back-end section also.  This feature makes it acceptable in the already designed/functioning classical homodyne architecture based receiver.


2001 ◽  
Vol 18 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Jon F. Bell ◽  
Peter J. Hall ◽  
Warwick E. Wilson ◽  
Robert J. Sault ◽  
Rick J. Smegal ◽  
...  

AbstractDigital signal processing is one of many valuable tools for suppressing unwanted signals or inter-ference. Building hardware processing engines seems to be the way to best implement some classes of interference suppression but is, unfortunately, expensive and time-consuming, especially if several miti-gation techniques need to be compared. Simulations can be useful, but are not a substitute for real data. CSIRO’s Australia Telescope National Facility has recently commenced a ‘software radio telescope’ project designed to fill the gap between dedicated hardware processors and pure simulation. In this approach, real telescope data are recorded coherently, then processed offline. This paper summarises the current contents of a freely available database of base band recorded data that can be used to experiment with signal processing solutions. It includes data from the following systems: single dish, multi-feed receiver; single dish with reference antenna; and an array of six 22 m antennas with and without a reference antenna. Astronomical sources such as OH masers, pulsars and continuum sources subject to interfering signals were recorded. The interfering signals include signals from the US Global Positioning System (GPS) and its Russian equivalent (GLONASS), television, microwave links, a low-Earth-orbit satellite, various other transmitters, and signals leaking from local telescope systems with fast clocks. The data are available on compact disk, allowing use in general purpose computers or as input to laboratory hardware prototypes.


Author(s):  
Ehsan Sheybani

Software-defined radios (SDR) are gradually becoming a practical option for implementing RF communication systems due to their low cost, off-the-shelf availability, and flexibility. Although the analog limitations of the hardware devices in these systems create barriers to some applications, creative algorithms in digital signal processing (DSP) can improve the results. In some cases, this improvement is essential to establishing a robust and reliable communication. The universal software radio peripheral (USRP) is a popular hardware that can be used alongside the SDR. Among many capabilities of USRP and its changeable daughter boards is receiving GPS signals. The GPS satellites transmit data on two main frequencies, L1 (1575.42 MHz) and L2 (1227.60 MHz). In this chapter, the focus is on describing a detailed implementation of the real-time DSP-based algorithm for USRP to detect GPS signal, namely the L1 band that transmits at 1575.42 MHz.


Sign in / Sign up

Export Citation Format

Share Document