Design and implementation of near-field measurement probes

The problems of electronics product because of electromagnetic incompatibility are in-creasing constantly. To end this incompatibility the European Union (EU) has decided to empower the Directive 2004/108/EC so devices could operate close to each other properly. The product manufacturers are required to make standardized tests to verify that the product is compliant with the Directive 2004/108/EC. Many times the designer uses a lot of time to design product functions and uses project time for verification of these functions. However, the final product should be tested in according the most recent electromagnetic standards and one of these many tests is the radio disturbance test as a function of frequency and for this disturbance the standard states limit values. This thesis is intended to bring out some phenomena by using calculations to show that how these limit values are easily broken if the product contains some design faults for example in the printed circuit board. The main focus is to design a near-field measure-ment probes which are electric field probes, magnetic field probes and a high-frequency current probe. The standardized test is done in the far field, and sometimes for the designer it is very difficult to spot the origin of interference. According the measurement results of this thesis the designed and implemented near-field probes can be used efficiently to locate the origin of interference. The magnetic field probe and electric field probe can be used to spot interference source from the printed circuit board (PCB) and high-frequency cur-rent probe can be used to search product external cable which carries common-mode current. According the calculations of this thesis the common-mode current is most problematic radiator from electronic product cabling.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Asystole episodes and bradycardia in patients with end-stage renal disease

Background Knowledge of arrhythmias in patients with end-stage renal disease (ESRD) is mainly based on ambulatory electrocardiography (ECG) studies and observations during haemodialysis (HD). We used insertable cardiac monitors (ICMs) to define the prevalence of arrhythmias, focusing on bradyarrhythmias, in ESRD patients treated with several dialysis modes including home therapies. Moreover, we assessed whether these arrhythmias were detected in baseline or ambulatory ECG recordings. Methods Seventy-one patients with a subcutaneous ICM were followed for up to 3 years. Asystole (>= 4.0 s) and bradycardia (heart rate = 4 beats) episodes, ventricular tachyarrhythmias and atrial fibrillation (AF) were collected and verified visually. A baseline ECG and a 24- to 48-h ambulatory ECG were recorded at recruitment and once a year thereafter. Results At recruitment, 44 patients were treated in in-centre HD, 12 in home HD and 15 in peritoneal dialysis. During a median follow-up of 34.4 months, 18 (25.4%) patients had either an asystolic or a bradycardic episode. The median length of each patient's longest asystole was 6.6 s and that of a bradycardia 13.5 s. Ventricular tachyarrhythmias were detected in 16 (23%) patients, and AF in 34 (51%) patients. In-centre HD and Type II diabetes were significantly more frequent among those with bradyarrhythmias, whereas no bradyarrhythmias were found in home HD. No bradyarrhythmias were evident in baseline or ambulatory ECG recordings. Conclusions Remarkably many patients with ESRD had bradycardia or asystolic episodes, but these arrhythmias were not detected by baseline or ambulatory ECG.Peer reviewe