Dear Siba,

In theory, all applications done for Signal Processing can be performed using VLSI, and all approaches used by VLSI field can contribute with SP field. Thus, it is a very deep and fruitful area.

Best,

Alisson

Almost all the applications of signal processing can be done using VLSI system design. While choosing the circuit one must take care of frequency of operation of the system while designing VLSI circuits.

VLSI is the basic building block of SP domain. More precisely An optimal signal proessing application is always developed using VLSI techniqus. Please try searching SCIENCE DIRECT and IEEE EXPLORER for the same. 

To get a clear idea about the latest trends in the area go through the latest issues of the following journals in signal processing

IEEE Signal Processing Magazine

IEEE Signal Processing Letters

Signal Processing: Image Communication

IET Signal Processing

EURASIP Journal on Advances in Signal Processing

Circuits, Systems, and Signal Processing- Springer

I would develop self-sustaining ultra low-power thermal energy harvesting wireless sensors for intra-body implant.

Any signal processing like audio, video and control based application integrated with VLSI domain. It may be FPGA implementation or ASIC implementation.

In VLSI design, timing analysis play major role and need to consider power consumption.