Digital peak programme meter for audio metering (also known as a digital level meter)  1LM21Dx with correlator measures the level and phase for digital audio, accept a digital audio input in AES/EBU and S/PDIF format. Primarily it is designed for recording and broadcasting studios.

The internal processing is in the digital domain, by means  of DSP (digital signal processor) toachieve all the stability and accuracy improvements associated with the digital technique.  AES/EBU input and output are ballanced and separated by transformers. The digital input and output are controlled by a Crystal CS8427 – stereo digital audio transceiver, whitch determines whether the input signal is in AES/EBU or S/PDIF format, and also detects information on preemphase and  the sample rate, which may be 32 kHz, 44,1 kHz or 48 kHz. Signal level is indicated by two orange bars on double 201-segment neon plasma bar graph display with standardized ballistic characteristic. Scale is generated electronically (pre-defined in the software). Based on this facts long term stability is garanteed. Adjustment and calibration are not required.

 The instrument includes additional features, like instant reading from the max., additional 20 dB gain, automatic or manual resetable memory for storing of maximum reading, 3 color LED compatibity meter.  Peak memory can also be activated at any time, with the MEM push-button or cleared with the RES push-buton. Reset is either automatic, manual or via the remote connector. The maximum signal level is indicated by a bar with half brightness. Integration time can be set between 1 sample and 10 ms. Using remote controller, it is possible to switch between  FAST and SLOW values. Exceeding of the OVeRload level is indicated by red LEDs and the level is adjustable. The indicators for overload work with adjustable hold function. On the front panel there is also push-button for switching  GAIN (+20 dB).

Correlation is displayed by 11-segment LED strip. The correlation meter, or phase meter, displays the average phase relationship between two audio signals. A stereo signal will ideally indicate “0 yellow”, which is random distributed phase. Mono will indicate “+1 green”, and reversed phased signal components will be indicated in the  “0 to -1 red” range.

Operating modes are set using internal switches and GPI remote control. If the signal level is not measureble for prolonged time, the level meter turns itself into standby mode. The level meter is available for vertical 1LM21AV or horizontal 1LM21AH mounting. Power is supplied from the external adaptor. The instrument is housed in a cabinet and is available for panel mount    ( 19“ / 1RU rack mount for two  1 0000 07 90 , rack mount for one 1 0000 07 80 or rack mount  5RU - 1 0055 34 00 for vertical scale) or for table top use.

The instrument fully complies with international standards   IEC 268-10 and IRT3.6.

Block diagram, Dimensions 1LM21Dx -

Catalog sheet (digital & analog version) (4,8MB)  -