Abstract:
In one embodiment, the invention is directed toward techniques for generating results in a logarithmic domain. The techniques may exploit properties of a logarithmic function to reduce the memoryrequirements needed to implement lookup tables. For example, the techniques may utilize non-uniform sampling over a logarithmic orlogarithmic-like function to reduce the number of entries needed for a given lookup table. In particular, the techniques may involve separating a number into an exponent component and a mantissa component. Each of these different components can then be converted from a first domain to a second domain using different lookup tables.
Abstract:
Techniques for controlling operation of control loops in a receiver are described. The operation of at least one control loop is modified in conjunction with a change in operating state, which may correspond to a change in linearity state, gain state, operating frequency, antenna configuration, etc. A change in linearity state may occur when jammers are detected and may cause bias current of analog circuit blocks to be adjusted. The at least one control loop to be modified may include a DC loop, an AGC loop, etc. The operation of a control loop may be modified by disabling the control loop or changing its time constant prior to changing operating state, waiting a predetermined amount of time to allow the receiver to settle, and enabling the control loop or restoring its time constant after waiting the predetermined amount of time.
Abstract:
An AMPS receiver system utilizing a ZIF architecture and processing received forward link signals in the digital domain. The AMPS receiver system includes an antenna (105), a direct converter (110), high dynamic A/D converters (120, 130), low pass filters (140, 150), a phase shifter (160), a digital FM demodulator (180), an accumulator (185) and a controller (190). The direct converter (110) further includes a low noise amplifier (112), a splitter (113), mixers (114, 116) and low pass filters (118, 119). The controller (190) adjusts the gains of the low noise amplifier (112) and the digital VGA (170) based on the average power of the signal outputted by the digital VGA (170).