Audio Precision音频分析仪测试介绍.pptVIP

AP Introduction THD + N Analyzer input and XLR connector AP Panel Audio specifications THD + N AP introduction Analyzer input cable connection - Single ended output (MP3 headphone) 2 – Signal, 3 – Ground. e.g., Channel A: 2 – Left output, 3 – Ground Channel B: 2 – Right output, 3 – Ground - Differential output (loudspeaker) 2 – Non-inverting signal, 3 – Inverting signal AP introduction XLR Connector AP introduction XLR Connector - In reference to its original manufacturer, James H. Cannon, founder of Cannon Electric in Los Angeles, California (now part of ITT Corporation), the connector is colloquially known as a cannon plug or cannon connector. - The most common is the 3-pin XLR3, used almost universally as a balanced audio connector for high quality microphones and connections between equipment. - XLR plugs and sockets are used mostly in professional audio and video electronics cabling applications. Home audio and video electronics normally use RCA connectors. AP introduction AP1 Panel AP introduction THD + N vs Level Curve AP introduction Analyzer Panel AP introduction Sweep Definitions Panel AP introduction Frequency Response - Frequency Response measurements are made by stepping or sweeping a sine wave oscillator, at a fixed amplitude, across the spectrum of interest. - Usually stated in terms of dB variation from some reference midband frequency(e.g., 1KHz). - The test may be easily modified. The frequency range and direction of sweep can be changed from the 20 KHz ~ 20 Hz stored by entering new values for START and STOP under SWEEP (F9) DEFINITIONS panel. AP introduction Signal to Noise Ratio - Signal to noise ratio, as a relative measurement, must be made with reference to a specific output amplitude from the device under test. - The rated output amplitude must be calibrated as the 0 dBr reference of the analyzer. Then the residual output amplitude (noise) is measured and expressed in dB relative to