title: Bipolar amplifier bias technique for robust IM3 null tracking independent of internal emitter resistance

authors: Balsom, Toby

abstract: Bipolar amplifiers can be biased to give a deep null in third order non-linearity, with the potential for high IP3 amplifier stages. This requires maintaining a precise voltage drop across a small resistive emitter degeneration resistance, whose value is related to kT/q. To make such a scheme practical, the bias must not only take into account the change in kT/q with temperature, but must compensate for variations in the degeneration resistance. In this paper we present a bias technique for IM3 null tracking that can take account of temperature and resistance tolerances, and is also insensitive to the value of the internal emitter resistance. Simulations using a 27 GHz BiCMOS technology indicate that the bias of an amplifier can be maintained over temperature, representative element tolerances, and mismatch such that the IP3 performance is maintained within ±9.5 dBV of the optimum null condition. The technique is applicable for a range of bipolar BiCMOS technologies and is attractive for amplifiers where high IP3 is required with moderate noise figure.

text: Bipolar amplifier bias technique for robust IM3 null tracking independent of internal emitter resistance Bipolar amplifiers can be biased to give a deep null in third order non-linearity, with the potential for high IP3 amplifier stages. This requires maintaining a precise voltage drop across a small resistive emitter degeneration resistance, whose value is related to kT/q. To make such a scheme practical, the bias must not only take into account the change in kT/q with temperature, but must compensate for variations in the degeneration resistance. In this paper we present a bias technique for IM3 null tracking that can take account of temperature and resistance tolerances, and is also insensitive to the value of the internal emitter resistance. Simulations using a 27 GHz BiCMOS technology indicate that the bias of an amplifier can be maintained over temperature, representative element tolerances, and mismatch such that the IP3 performance is maintained within ±9.5 dBV of the optimum null condition. The technique is applicable for a range of bipolar BiCMOS technologies and is attractive for amplifiers where high IP3 is required with moderate noise figure.

year: 2012

title: Simultaneous phase and frequency stepping in Time-of-flight range imaging

authors: Lickfold, Carl A.

subjects: Time-of-flight

abstract: Time-of-flight (ToF) range imaging is an established full-field depth acquisition technology. ToF is prone to several forms of error, notably multi-path interference (MPI). Frequency stepping ToF mitigates these errors, but efficient computational methods suffer from bandwidth limitations. We introduce a new acquisition method based on simultaneous phase and frequency stepping, which is capable of running in real time and reduces error compared to phase stepping and frequency stepping alone.

text: Simultaneous phase and frequency stepping in Time-of-flight range imaging Time-of-flight (ToF) range imaging is an established full-field depth acquisition technology. ToF is prone to several forms of error, notably multi-path interference (MPI). Frequency stepping ToF mitigates these errors, but efficient computational methods suffer from bandwidth limitations. We introduce a new acquisition method based on simultaneous phase and frequency stepping, which is capable of running in real time and reduces error compared to phase stepping and frequency stepping alone.

year: 2019

title: Waiwharangi

authors: Maxwell, Te Kahautu

abstract: Haka. Lyrics/Musical score composed by Te Kahautu Maxwell. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (4mins)

Waiata: Tira Aroha
Whakaeke: Haere mai rā
Mōteatea: Te Pātere a Te Turuki
Poi: Iarararararī
Waiata ā ringa: Taku Mana Māori Motuhake
Haka: Waiwharangi
Whakawātea: Āio

text: Waiwharangi Haka. Lyrics/Musical score composed by Te Kahautu Maxwell. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (4mins)

Waiata: Tira Aroha
Whakaeke: Haere mai rā
Mōteatea: Te Pātere a Te Turuki
Poi: Iarararararī
Waiata ā ringa: Taku Mana Māori Motuhake
Haka: Waiwharangi
Whakawātea: Āio

year: 2020-02-06