Kaedah Relatif Untuk Penentuan Nilai Pembetulan Medan Bebas Mikrofon Pengukuran Bunyi
DOI:
https://doi.org/10.11113/jt.v64.1163Keywords:
Pembetulan medan bebas, tentukuran medan bebas mikrofon, tentukuran medan tekanan mikrofon, mikrofon pengukuran, kaedah relatifAbstract
Nilai pembetulan medan bebas adalah nilai yang digunakan untuk menukarkan sambutan tekanan mikrofon pengukuran bunyi semasa tentukuran kepada sambutan medan bebas. Kaedah perbandingan relatif telah dibangunkan untuk menentukan nilai pembetulan medan bebas sebagai pilihan kepada kaedah mutlak yang sediada. Sambutan medan tekanan telah dibandingkan secara relatif dengan medan bebas. Sambutan mikrofon di dalam setiap medan diperolehi secara perbandingan dengan mikrofon standard makmal yang telah diketahui nilai pembetulan medan bebasnya. Kedua-dua mikrofon didedahkan secara berturutan kepada sumber bunyi dengan aras tekanan bunyi yang sama di dalam medan bebas dan medan tekanan dan voltan keluaran AC akan diukur. Medan bebas dihasilkan di dalam kebuk nirgema dan medan tekanan di dalam pengganding penentukur bunyi. Nilai pembetulan medan bebas untuk dua mikrofon yang telah diketahui nilainya dari pembuat telah ditentukan dan dibandingkan untuk tujuan pengesahan kaedah. Keputusan perbandingan kedua-dua mikrofon yang saling menepati setelah mengambil kira ketidakpastiannya menunjukkan kaedah relatif boleh digunakan.
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