title: A simple microcontroller based digital lock-in amplifier for the detection of low level optical signals

authors: Dorrington, Adrian A.

subjects: digital lock-in amplifier

abstract: Traditionally digital lock-in amplifiers sample the input signal at a rate much higher than the lock-in reference frequency and perform the lock-in algorithm with high-speed processors. We present a small and simple digital lock-in amplifier that uses a 20 bit current integrating analogue-to-digital converter interfaced to a microcontroller. The sample rate is set to twice the reference frequency placing the sampled lock-in signal at the Niquest frequency allowing the lock-in procedure to be performed with one simple algorithm. This algorithm consists of a spectral inversion technique integrated into a highly optimised low-pass filter. We demonstrate a system with a dynamic range of 103dB recovering signals up to 85dB below the interference.

text: A simple microcontroller based digital lock-in amplifier for the detection of low level optical signals Traditionally digital lock-in amplifiers sample the input signal at a rate much higher than the lock-in reference frequency and perform the lock-in algorithm with high-speed processors. We present a small and simple digital lock-in amplifier that uses a 20 bit current integrating analogue-to-digital converter interfaced to a microcontroller. The sample rate is set to twice the reference frequency placing the sampled lock-in signal at the Niquest frequency allowing the lock-in procedure to be performed with one simple algorithm. This algorithm consists of a spectral inversion technique integrated into a highly optimised low-pass filter. We demonstrate a system with a dynamic range of 103dB recovering signals up to 85dB below the interference.

year: 2002

title: Becoming a Teacher: An Investigation of the Transition from Student Teacher to Teacher

authors: Grudnoff, Alexandra Barbara

subjects: teacher preparation programmes

abstract: This thesis seeks to gain greater knowledge of the process of transition and
development that beginning primary teachers undergo over their first year of
teaching. The research focus is on investigating and understanding this process
from the standpoint of the beginning teacher. Of particular interest is an
examination of how the teacher preparation programme, contextual features of the
school, and participants' own beliefs and biographies influence and impact on
their transition to teaching and their professional and identity development as first
year teachers.
This longitudinal study takes an interpretive approach to investigate the first year
teaching experiences of 12 beginning teachers in 11 primary schools. The
qualitative methodology used in this thesis shares characteristics with a case study
approach and utilizes procedures associated with grounded theory. Data were
gathered systematically over a year by way of 48 semi-structured, individual
interviews, two focus group interviews, and 48 questionnaires, supplemented by
field notes. The collected data were analyzed, coded, and categorized, and
explanations and theory that emerged from this process were grounded in the data.
The findings of this study have three broad sets of implications for the education
and induction of beginning teachers.
Firstly, they question the role that practicum plays in the transition from
student to teacher. The findings suggest that the practicum component of
teacher preparation programmes should be re-conceptualized and redesigned
to provide authentic opportunities for student teachers to be
exposed to the full range of work demands and complexity that they will
encounter as beginning teachers.
Secondly, becoming a successful teacher appears to depend on the quality
of the school's professional and social relationships, particularly in terms
of the frequency and type of formal and informal interactions that
ii
beginning teachers have with colleagues. While the major source of
satisfaction and self-esteem came from seeing the children whom they
taught achieving socially and academically, the beginning teachers also
had a strong need for affiliation, which was enabled through positive,
structured interactions and relationships with colleagues. The study also
indicates that employment status influences the way that the beginning
teachers view their work and themselves as teachers, with those in
relieving positions displaying greater variability in terms of emotional
reactions and a sense of professional confidence than those employed in
permanent positions.
The third set of implications relate to beginning teacher induction. The
study points to variability in the quality of induction experiences and
challenges policy makers and principals to ensure that all beginning
teachers are provided with sound and systematic advice and guidance
programmes which are necessary for their learning and development.
While the study confirms the critical role played by tutor teachers in
beginning teacher induction, it suggests that the focus is on emotional and
practical support rather than on educative mentoring to enhance new
teachers' thinking and practice.
This thesis provides a comprehensive and nuanced view of how beginning to
teach is experienced and interpreted. It paints a complex picture of the
relationship between biography, beliefs, preparation, and context in the process of
learning to teach. The study contributes to the literature on the education of
beginning teachers. It highlights the need for developing a shared understanding
amongst policy makers, teacher educators, and schools regarding the multiplicity and complexity of factors that influence the transition and development of beginning teachers.

text: Becoming a Teacher: An Investigation of the Transition from Student Teacher to Teacher This thesis seeks to gain greater knowledge of the process of transition and
development that beginning primary teachers undergo over their first year of
teaching. The research focus is on investigating and understanding this process
from the standpoint of the beginning teacher. Of particular interest is an
examination of how the teacher preparation programme, contextual features of the
school, and participants' own beliefs and biographies influence and impact on
their transition to teaching and their professional and identity development as first
year teachers.
This longitudinal study takes an interpretive approach to investigate the first year
teaching experiences of 12 beginning teachers in 11 primary schools. The
qualitative methodology used in this thesis shares characteristics with a case study
approach and utilizes procedures associated with grounded theory. Data were
gathered systematically over a year by way of 48 semi-structured, individual
interviews, two focus group interviews, and 48 questionnaires, supplemented by
field notes. The collected data were analyzed, coded, and categorized, and
explanations and theory that emerged from this process were grounded in the data.
The findings of this study have three broad sets of implications for the education
and induction of beginning teachers.
Firstly, they question the role that practicum plays in the transition from
student to teacher. The findings suggest that the practicum component of
teacher preparation programmes should be re-conceptualized and redesigned
to provide authentic opportunities for student teachers to be
exposed to the full range of work demands and complexity that they will
encounter as beginning teachers.
Secondly, becoming a successful teacher appears to depend on the quality
of the school's professional and social relationships, particularly in terms
of the frequency and type of formal and informal interactions that
ii
beginning teachers have with colleagues. While the major source of
satisfaction and self-esteem came from seeing the children whom they
taught achieving socially and academically, the beginning teachers also
had a strong need for affiliation, which was enabled through positive,
structured interactions and relationships with colleagues. The study also
indicates that employment status influences the way that the beginning
teachers view their work and themselves as teachers, with those in
relieving positions displaying greater variability in terms of emotional
reactions and a sense of professional confidence than those employed in
permanent positions.
The third set of implications relate to beginning teacher induction. The
study points to variability in the quality of induction experiences and
challenges policy makers and principals to ensure that all beginning
teachers are provided with sound and systematic advice and guidance
programmes which are necessary for their learning and development.
While the study confirms the critical role played by tutor teachers in
beginning teacher induction, it suggests that the focus is on emotional and
practical support rather than on educative mentoring to enhance new
teachers' thinking and practice.
This thesis provides a comprehensive and nuanced view of how beginning to
teach is experienced and interpreted. It paints a complex picture of the
relationship between biography, beliefs, preparation, and context in the process of
learning to teach. The study contributes to the literature on the education of
beginning teachers. It highlights the need for developing a shared understanding
amongst policy makers, teacher educators, and schools regarding the multiplicity and complexity of factors that influence the transition and development of beginning teachers.

year: 2007

title: Prismatic storying: Making visible multi coloured codes

authors: Stuart, Margaret J.

abstract: Language is a casement into cultures' deepest meanings. As children acquire languages, they implicitly adopt the mores of people around them; read the symbols, artefacts and codes. In this article, we examine the importance of language and literacy in the early childhood curriculum Te Whariki: He Whariki Matauranga mo nga Mokopuna o Aotearoa/Early Childhood Curriculum (Ministry of Education, 1996). The focus of the article is on literacy from a bicultural perspective. Adults support children in finding out about both their social and physical worlds. They use their 'imaginations to explore their own and others' identities' (MoE, 1996, p. 25). Our aim is to offer teachers in mainstream early childhood centres (ECE) strategies to apply, practise and situate literacy approaches that reflect Te Ao Maori through stories reflecting symbolic representations of people, places and things.

text: Prismatic storying: Making visible multi coloured codes Language is a casement into cultures' deepest meanings. As children acquire languages, they implicitly adopt the mores of people around them; read the symbols, artefacts and codes. In this article, we examine the importance of language and literacy in the early childhood curriculum Te Whariki: He Whariki Matauranga mo nga Mokopuna o Aotearoa/Early Childhood Curriculum (Ministry of Education, 1996). The focus of the article is on literacy from a bicultural perspective. Adults support children in finding out about both their social and physical worlds. They use their 'imaginations to explore their own and others' identities' (MoE, 1996, p. 25). Our aim is to offer teachers in mainstream early childhood centres (ECE) strategies to apply, practise and situate literacy approaches that reflect Te Ao Maori through stories reflecting symbolic representations of people, places and things.

year: 2018