Analog peak programme meter for audio metering (also known as a analog level meter) 1LM21Ax  with correlator measures the level and phase of the stereo signal. Primarily it is designed for recording and broadcasting studios.

The internal processing of the analog signal is carried out in the digital domain, by means  of  DSP (digital signal processor) to achieve all the stability and accuracy improvements associated with the digital technique. The analog signal is converted by means of  S-D18 bit A/D converters at 48 kHz sampling rate.

Inputs are ballanced and separated by transformers. Signal level is indicated by two orange bars on double 201-segment neon plasma bar graph display. The signal is displayed with standardized ballistic characteristic. PPM and VU scales are generated electronically (pre-defined in the software) and have a common point at the level of 0 dB. They can also be used simultaneously.  Based on this facts long term stability is garanteed. Adjustment and calibration are not required.

The reference level of this scale (0 dB reading) can be set to a value between 0 and 15 dBu by DIP switch. 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). Using RES button, with the memory of maximums deactivated, we can select scales  PPM, VU, or both PPM+VU at the same time.

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 1LM21Ax -

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