Closed loop analysis of a triangular wave generator (Closed loop system analysis of triangular wave generator consisting of integrator, on-off element with hysteresis and multiplier)

Applications requiring a triangular wave generator that gives a symmetrical output, and the frequency of which can be varied over a wide range by an external input voltage, are many-fold. The theoretical basis for the design of such a system has been presented here, based on the closed loop analysis. A scheme for practical implementation that uses integrated circuit blocks, is also provided. The circuit described by Klein and Hagenbeuk (1907) for this purpose, however, uses only discrete components

EPIDEMIOLOGICAL STUDY ON HEAD AND NECK MALIGNANCIES - A STUDY OF 150 CASES

OBJECTIVE: In the present study we investigate the head and Neck Malignancy cases presenting to the ENT department of our Hospital, and analyze the same to give inputs as to the incidence of head and neck malignancies, the symptoms and stage of presentation, lifestyle and habits as contributory risk factors, identify ENT primary in neck secondaries, histopathological types and selection of best treatment.METHODS: Prospective analysis of 150 patients with newly diagnosed malignancies of nasopharynx, oropharynx, larynx, hypopharynx and ear.RESULTS: Most malignancies are common in patients greater than 40 years of age. 88% of cancer occur in males. Oropharynx cancer is the most common cancer in our study, with the commonest subsite as base of tongue. Supraglottic and pyriform fossa tumours are the commonest tumour in laryngeal and hypopharyngeal cancers  respectively. The most common presentation is dysphagia. Synergistic effect of smoking and alcohol is seen in 50% of patients. Most of the cases were seen in stage III and IV except glottis cancer which is predominantly seen in stage I, almost all cases were squamous cell carcinoma.CONCLUSION:The results of our study were in conformity with other similar studies. In larynx, Supraglottic was more common as opposed to glottis in certain western studies. Analysis of various factors helps in early diagnosis and management.KEYWORDS:Cancer, Head and Neck Malignancy, Larynx, pharynx, Nasopharynx, Neck secondaries.

A novel 90xB0; phase shifter for square waves

In the field of electronic instrumentation there are many applications where a circuit is needed to shift the use of square waves by 90xB0;. In this paper a simple and novel scheme to achieve this end is proposed. This circuit, along with a modulo-two-adder, also enables one to obtain the double frequency component of the original input square wave. It is thus possible to have frequency multiplication by powers of two by cascading such circuits in tandem. The entire circuitry, excepting the time averaging capacitors, can be either13; integrated in one chip or fabricated in tins module form