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HCD标准测试带是电视、电声研究所研制的。它用于调整、检测盒式磁带录音机的性能指标,也可用于测量磁头和磁带的有关技术参数。现将比较成熟的五种HCD测试带的规格性能介绍如下。1.HCD-311参考磁平测试带(简称磁平带) 磁平带上录有频率为315Hz的正弦波全轨迹信号,其短路带磁通为250nWb/M(10~(-9)韦伯/米)。重放此磁平带所得输出即为0dB磁平。HCD-311磁平带的信号频率偏差小于±0.5%,幅度误差小于±0.5dB,电平波动小于0.5dB,谐波失真小于3%,放音时间为15分钟。见图1所示。磁平带用于确定录音机的额定放音状态,亦可与录放音输出电平进行相对比较,而确定录音磁平的分贝值。
HCD standard test strip is developed by the Institute of Television, electro-acoustic. It is used to adjust, test the performance of the tape recorder, can also be used to measure the head and tape related technical parameters. Now more mature five kinds of HCD test strip specifications performance are as follows. 1. HCD-311 reference magnetic flat test zone (magnetic flat belt) recorded on the magnetic flat belt with a frequency of 315Hz sinusoidal full-track signal, the short-circuit flux of 250nWb / M (10 -9 Weber / Meter). Replay of the magnetic flat belt output is 0dB magnetic level. HCD-311 magnetic flat belt signal frequency deviation of less than ± 0.5%, amplitude error of less than ± 0.5dB, level fluctuations of less than 0.5dB, harmonic distortion of less than 3%, playback time of 15 minutes. See Figure 1 below. The magnetic flat belt is used to determine the rated playback status of the recorder. It can also be compared with the recording and playback output level to determine the decibel value of the recording magnetic level.