1、Summary
　 JH1-HS5920 type noise monitor is a pocket noise measure apparatus,is is displayed to be “A” sound
grade by LCD,and it has function of “maximum keep”
and “sound grade enactment”,also it can be used for measure of ambient noise machine noise,vehicle niose , electrical machinery noise,architecture acoustics and electroacoustics.

2、main technical performance
　　microphone：use HS14421 electret test microphone
　　frequency response：20——1250Hz
　　standard sensitivity ：25mV/Pa
　　sound measure range：（consult 2×10-5Pa）
　　L：40—95dB
　　H：80—130dB
　　function ：40—140DB
　　frequency range and trait of frequency calculation：
　　frequency range ：31.5Hz～8kHz
　　frequency calculation：A calculation accords with standard of IEC615 and GB3785—83 sound meter as well as
    requirement of Ⅱtype machine
　　H．Distance switch error of H．L: ≤±0.5dB
　　trait of display：
　　a:digital automatic display,circulation time is one time one second
　　b：Resolution ratio is better than 0.1dB
　　cymoscope trait：LMS real virtual value
　　tiem calculation:F(fast) accords with IEC651 standard (sound meter) and requirement of national standard  
    GB3785—83Ⅱtype machine.
　　attenuation speed is less than 1dB/min
　　accord with IEC651 and GB3785—83 standard as well as requirement of Ⅱ type machine of GB3785—83 standard.
　　adjustment：adjust with ND9 sound regulator （94dB1KHz）
　  power:one 9V layer batteries,can work for more than successive eight hours (ill-pressure display:while power
    pressure is lower than 7.5±0.5V,display shows “：”
　　use condition：：surrounding temperature：0—40℃
　　atmospheric pressure：86—106KPa
　　surrounding temperature：（20—90%RH(+40℃ Hour)
　　Size：L×B×hmm：118×60×23
　　weight：0.18KG（including batteries）
　　influence of sound field:when equivalent resistance replaces electret microphone,put apparatus in sound field,
    figure on apparatus is 30dB lower than this sound field at least.
　　influence of magnetic field:when apparatus is put in magnetic field of which the frequency is 50Hz and 
    intensity of magnetic field is 80A/m,owing to influence of magnetic field the change of apparatus sensitivity
    is not more than 0.5dB.
　　Main accessories:one wind-cover,one battery,two instructions,32mm minitype plastic-handle opener and one 
   packaging bag.