NL-28聲級計是日本理音推出的聲級計，NL-28是替代原來NA-27的新產品!

Sound Level Meter1/3 octave band real-time analyzer NA-28

1. Real Time Octaves （16 Hz to 16 kHz） or 1/3 octaves （12.5 Hz to 20 kHz）
2. Real Time Simultaneous Octaves （16Hz to 8kHz）1/3 Octaves （12.5Hz to 12.5kHz）
3. Data stored as text files direct to CF card
4. Measureslogs eq, max, min5 percentile values （LN） in octaves and/or 1/3 octaves
5. Auto Stores 300 000 data sets or 1 000 hours of 1 second 1/3 octaves onto 1 GB CF card
6. Auto Stores 1000 data sets or 10 000 of 1 second 1/3 octaves to internal memory
7. Manual Storage for 1 000 data sets internally or 100 000 data sets to 1 GB CF card
8. Linearity 110 dB in Sound Level Meter Mode95 dB in Analyzer Mode
9. 16 hours battery life with 4 Alkaline"C" Cells
10. MainSub-Channel for simultaneous selection of 2 time or frequency weightings F（Fast）, S（Slow）, 10 ms Time Weightings plus Peak & Impulse on Sub-Channel
11. Data transfer using CF card or USB （meter/CF card appearing as virtual disk）
12. Measurement can be started by internal or external trigger
13. Comparator output to trigger external devices
14. ACDC outputs of main and/or sub-channel
15. Expandable functionality using programme cards
16. IEC 61672-1:2002 Class 1，IEC 61260:1995 Class1，ANSI S1.4-1983 Type 1，ANSI S1.11-2004 Class 1

Specification 

Applicable specifications	IEC 61672-1:2002 Class 1, IEC 61260:1995 Class 1, ANSI S1.4-1983 Type 1, ANSI S1.11-2004 Class 1
Measurement functions	With both a sound level meter modeanalyzer mode, it is capable of simultaneous main channelsub-channel measurement in either mode. Timefrequency weighting are set separay for the mainsub-channels.
Measurement modes	Sound level meter mode: Measurement of all-pass values indicated in the measurement items below in the main or sub-channel, Measurement of either Lpeak or Ltm5 in the sub-channel Analyzer mode : Real-time octave1/3 octave band analysisall-pass measurement in the main channel, Only all-pass measurement in the sub-channel
Measurement items	Simultaneous measurement of all items in the selected time weightingfrequency weighting characteristics Instantaneous sound pressure level Lp, Equivalent continuous sound pressure level Leq, Sound exposure level LE, Maximum sound pressure level Lmax, APMaxBandMax can be selected as maximum, Minimum sound pressure level Lmin, Maximum 5 time ratio sound level LN （1 to 99%, 1% Step）, Calculation from Lp or Leq 1sec
Measurement time	1 to 59 sec, 1 to 59 min, 1 to 24 hours
Microphonepreamplifier	Microphone UC-59, Preamplifier NH-23
Measurement range	A: 25-130dB, C: 33-130dB, Z: 38-130dB
Frequency Range	10 Hz-20 kHz
Time weighting	Main:Fast, Slow, 10ms Sub:Fast, Slow, 10ms, Impulse
Display	Color semi-transparent TFT-LCD display with backlight （240 X 320 dots）
Power requirement	Four IEC R14P （size"C"） batteries or external power supply Operating time Manganese batteries: R14PU, 6 hours Alkaline batteries: LR14, 16 hours （10 hours if backlight is continuously activated）
Dimensionsweight	331 （H） X 89 （W） X 51 （D） mm , approx. 730 g （including batteries）