Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Frequency-oriented sub-sampling by photonic Fourier transform and I/Q
  demodulation   Sub-sampling can acquire directly a passband within a broad radio frequency
(RF) range, avoiding down-conversion and low-phase-noise tunable local
oscillation (LO). However, sub-sampling suffers from band folding and
self-image interference. In this paper we propose a frequency-oriented
sub-sampling to solve the two problems. With ultrashort optical pulse and a
pair of chromatic dispersions, the broadband RF signal is firstly short-time
Fourier-transformed to a spectrum-spread pulse. Then a time slot, corresponding
to the target spectrum slice, is coherently optical-sampled with
in-phase/quadrature (I/Q) demodulation. We demonstrate the novel bandpass
sampling by a numerical example, which shows the desired uneven intensity
response, i.e. pre-filtering. We show in theory that appropriate time-stretch
capacity from dispersion can result in pre-filtering bandwidth less than
sampling rate. Image rejection due to I/Q sampling is also analyzed. A
proof-of-concept experiment, which is based on a time-lens sampling source and
chirped fiber Bragg gratings (CFBGs), shows the center-frequency-tunable
pre-filtered sub-sampling with bandwidth of 6 GHz around, as well as imaging
rejection larger than 26 dB. Our technique may benefit future broadband RF
receivers for frequency-agile Radar or channelization.

18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas