Tolerancing and corner cases in optical simulation

ABSTRACT Our work discusses the tolerance modeling of an optical fiber that is inserted into a cylindrical alignment bore. We note that some commercial optical simulation software suites have the mechanical tolerance operands entered in Cartesian coordinates and if radial variation is entered as simple X and Y de-centering, there arises a kind of "corner condition" where fiber in the opto-mechanical model is offset more than is possible in the physical implementation resulting in an overly-conservative estimate of the worst-case coupling efficiency. Approaches to avoid this over estimation are presented and discussed

A universal low-noise analog receiver baseband in 65-nm CMOS

In this paper, a novel universal receiver baseband approach is introduced. The chain includes a post-mixer noise shaping blocker pre-filter, a programmable-gain post mixer amplifier (PMA) with blocker suppression, a differential ramp-based novel linear-in-dB variable gain amplifier and a Sallen–Key output buffer. The 1.2-V chain is implemented in a 65-nm CMOS process, occupying a die area of 0.45 mm2. The total power consumption of the baseband chain is 11.5 mW. The device can be tuned across a bandwidth of 700-KHz to 5.2-MHz with 20 kHz resolution and is tested for two distinct mobile-TV applications; integrated services digital broadcasting-terrestrial ISDB-T (3-segment f c = 700 kHz) and digital video broadcasting-terrestrial/handheld (DVB-T/H f c = 3.8 MHz). The measured IIP3 of the whole chain for the adjacent blocker channel is 24.2 and 24 dBm for the ISDB-T and DVB-T/H modes, respectively. The measured input-referred noise density is 10.5 nV/sqrtHz in DVB-T/H mode and 14.5 nV/sqrtHz in ISDB-T mode

A universal low-noise analog receiver baseband in 65-nm CMOS

In this paper, a novel universal receiver baseband approach is introduced. The chain includes a post-mixer noise shaping blocker pre-filter, a programmable-gain post mixer amplifier (PMA) with blocker suppression, a differential ramp-based novel linear-in-dB variable gain amplifier and a Sallen–Key output buffer. The 1.2-V chain is implemented in a 65-nm CMOS process, occupying a die area of 0.45 mm2. The total power consumption of the baseband chain is 11.5 mW. The device can be tuned across a bandwidth of 700-KHz to 5.2-MHz with 20 kHz resolution and is tested for two distinct mobile-TV applications; integrated services digital broadcasting-terrestrial ISDB-T (3-segment f c = 700 kHz) and digital video broadcasting-terrestrial/handheld (DVB-T/H f c = 3.8 MHz). The measured IIP3 of the whole chain for the adjacent blocker channel is 24.2 and 24 dBm for the ISDB-T and DVB-T/H modes, respectively. The measured input-referred noise density is 10.5 nV/sqrtHz in DVB-T/H mode and 14.5 nV/sqrtHz in ISDB-T mode

A universal low-noise analog receiver baseband in 65-nm CMOS

In this paper, a novel universal receiver baseband approach is introduced. The chain includes a post-mixer noise shaping blocker pre-filter, a programmable-gain post mixer amplifier (PMA) with blocker suppression, a differential ramp-based novel linear-in-dB variable gain amplifier and a Sallen–Key output buffer. The 1.2-V chain is implemented in a 65-nm CMOS process, occupying a die area of 0.45 mm2. The total power consumption of the baseband chain is 11.5 mW. The device can be tuned across a bandwidth of 700-KHz to 5.2-MHz with 20 kHz resolution and is tested for two distinct mobile-TV applications; integrated services digital broadcasting-terrestrial ISDB-T (3-segment f c = 700 kHz) and digital video broadcasting-terrestrial/handheld (DVB-T/H f c = 3.8 MHz). The measured IIP3 of the whole chain for the adjacent blocker channel is 24.2 and 24 dBm for the ISDB-T and DVB-T/H modes, respectively. The measured input-referred noise density is 10.5 nV/sqrtHz in DVB-T/H mode and 14.5 nV/sqrtHz in ISDB-T mode

Global COVID-19 lockdown highlights humans as both threats and custodians of the environment

The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence. However, negative effects of lockdown on conservation also emerged, as confinement resulted in some park officials being unable to perform conservation, restoration and enforcement tasks, resulting in local increases in illegal activities such as hunting. Overall, there is a complex mixture of positive and negative effects of the pandemic lockdown on nature, all of which have the potential to lead to cascading responses which in turn impact wildlife and nature conservation. While the net effect of the lockdown will need to be assessed over years as data becomes available and persistent effects emerge, immediate responses were detected across the world. Thus initial qualitative and quantitative data arising from this serendipitous global quasi-experimental perturbation highlights the dual role that humans play in threatening and protecting species and ecosystems. Pathways to favorably tilt this delicate balance include reducing impacts and increasing conservation effectiveness