Arrow sound indicator on the LCD display. Details and setup

Balanced analog audio signal level meter MS-23AS

Level meter for symmetrical analog audio signals type MS-23AS The meter allows you to visually control the quasi-peak level of two signals (stereo pair or two independent signals) and display them in a visual form. LED emitters of various colors with a large glow area and a wide viewing angle provide high reliability and operator comfort. Display of level - the shining chain of light-emitting diodes of green, yellow and red colors. At a level below 0 dB, the LEDs are green, above - red. If necessary, yellow divisions can be “superimposed” on the luminous chain of LEDs - either only “0dB”, or a grid in 20-10 dB.

• A pair of signals is equipped with a circuit for measuring the cross-correlation of signals, displayed as a separate two-color LED, green for in-phase signals, red for anti-phase signals. The correlometer can be turned off when working with independent signals.
• A separate rear-panel "GND lift" switch disconnects pins 1 of the input and output jacks from the body of the instrument, which is useful in harsh ground conditions.
• In addition to measuring and indicating, the device allows you to detect long pauses or low levels in signals and signal them with an audible signal and blinking of the scale LEDs. This feature can be disabled per channel or completely. The cut level can also be selected with a switch on the rear wall - below -30 dB for more than 5 seconds or below -40 dB for more than 10 seconds. To activate the missing control function, the switch sliders on the rear panel and the buttons on the front panel are used.
• Instead of dropout control, the front panel buttons can be used to expand the scale at three points - -10dB, 0dB, +8dB. Choice of control of loss or stretching - the switch on the back panel.
• Most switchable operating modes are selected by an eight-way switch on the rear panel. There is also an RS-485 interface connector, which allows organizing, if necessary, remote control of the meter functions and transmission of measured data, information about the loss to a PC or a remote display panel.

Balanced analog audio level meter MS-24AS2

The level meter for symmetrical analog audio signals type MS-24AS2 is intended for use in editing and on-air broadcasting and television hardware. The meter allows you to visually control the quasi-peak level of two pairs of signals (two stereo pairs or four independent signals) and display them in a visual form. LED emitters of various colors with a large glow area and a wide viewing angle provide high reliability and operator comfort. Display of level - the shining chain of light-emitting diodes of green, yellow and red colors. At a level below 0 dB, the LEDs are green, above - red. If necessary, yellow divisions can be "superimposed" on the luminous chain of LEDs - either only "0dB", or a grid in 20-10 dB.

• A wide range of measured signals (-50..+8 dB), stability of characteristics and a large number of displayed level gradations (50) guarantee high quality and convenience of measurements.
• The indication scale is logarithmic with a stretch around 0 dB. One division in the range -50 .. -10 dB corresponds to 2 dB, in the region of 0 dB - 0.5 or 0.66 dB. The set sensitivity levels correspond to the moment when the corresponding LED starts to light up.
• Functionally, the indicator corresponds to a group I quasi-peak meter according to GOST 21185-75 (DIN 45406) ​​with an averaging time of 5 ms (-2 dB) and a decay of 1.7 s / 20 dB.
• Each pair of signals is equipped with a circuit for measuring the cross-correlation of signals, displayed as a separate luminous column of LEDs, green for in-phase signals, red for anti-phase signals. The entire linear scale of 23 three-color LEDs corresponds to the range of the correlation coefficient -1..+1. The measured value is displayed when the level of both signals of the stereo pair is not lower than -30 dB. Rise and fall time of readings - 3 sec. The correlometer can be turned off when working with independent signals.
• The inputs of all channels can be configured either as high-impedance, working "through" (10 kOhm), or as low-impedance (600 Ohm). Switching of a configuration - switches on a back wall. The level of input signals can be adjusted stepwise (+6dB) - by jumpers on the board, under the cover, and smoothly - by "slotted" regulators placed on the rear wall next to the corresponding connector.
• When using "on the way" the indicator passes the signal without distortion, because. the output connectors are directly connected to the input ones, which allows you to include the device in a line break.
• In addition to measuring and indicating, the device allows you to detect long pauses or low levels in signals and signal them with an audible signal and blinking of the scale LEDs. This feature can be disabled per channel or completely. The cut level can also be selected with a switch on the rear wall - below -30 dB for more than 5 seconds or below -40 dB for more than 10 seconds.
• Most switchable operating modes are selected by an eight-way switch on the rear panel.
• The level indicator is made in the form of one 19-inch unit with a height of 1U and dimensions of 483x125x44 mm, intended for rack installation.
• Power supply of the device - 220+20V, 50 Hz, not redundant.

Audio Level Meter MS-25AS

MS-25AS audio signal level meter is intended for use in editing and on-air broadcasting and television control rooms.

• The meter accepts analog balanced signals or digital serial audio signals in AES-EBU (AES3) format at a sample rate of only 48 kHz. (This restriction will be lifted in future versions).
• The meter allows you to visually control the quasi-peak level of two signals (stereo pair or two independent signals) and display them in a visual form.
• Display of level - the shining chain of light-emitting diodes of green, yellow and red colors. At a level below 0 dB, the LEDs are green, 0 dB above are red. If necessary, yellow divisions can be “superimposed” on the luminous chain of LEDs - either only “0dB”, or a grid in 20-10 dB.
• A wide range of measured signals (-50..+8 dB for analog and -60..0 dBfs for digital signals), stability of characteristics and a large number of displayed level gradations (48) guarantee high quality and convenience of measurements.
• The level indicator is made in the form of a single block 240x100x80 mm in size, intended for installation on a horizontal surface.
• Power supply of the device - 12V, 0.3A, the kit includes a network adapter 220 + 20V, 50 Hz.
• Number of inputs 2 analog, 1 stereo AES|EBU
• Type of inputs differential, electronic
• Input impedance (switch selectable) 600 ohm / 10 k ohm, 110 ohm
• Nominal input level (switch selectable) +0 dBm (factory setting)
• Limits of regulation of nominal sensitivity (level "0 dB") -6..+6 dBm
• Quasi-peak detector integration time constant 5 ms (-2 dB)
• Indication decay time 1.7 sec / 20 dB, 5 sec full scale
• Maximum input level 10 V
• Permissible overloads (with a duration of up to 5 μs) up to 200 V
• Number of level indication steps 48
• Scale type piecewise logarithmic with a stretch around 0 dB
• Geometric scale length 127 mm
• Measurement range -50 ..+8 dB
• Operating frequency range 20 Hz-20 kHz at 0 dB level
• Measurement accuracy at 0 dB, 1 kHz + 0.1 dB
• Measurement accuracy at -40 dB level, 1 kHz + 2 dB
• Sensitivity unevenness in the range of 20Hz-20kHz (at 0 dB) less than 1 division of the main scale
• I/O connector type XLR ("Cannon")
• Supply voltage 10-16V 0.3A
• Overall dimensions 240x100x88 mm

Four-channel monitor of balanced analog stereo audio signals MS-26AK

• Designed for use in editing and on-air broadcasting and television hardware.
• Allows you to listen, measure the level of four analog stereo audio signals (four stereo pairs or eight independent signals) and display them in a visual form.
• Display of level - the shining chain of light-emitting diodes of green, yellow and red colors. At a level below 0 dB, the LEDs are green, 0 dB above are red. The indication scale is logarithmic with a stretch around 0 dB.
• Each pair of signals is equipped with a signal cross-correlation measurement circuit, displayed as a separate two-color LED, green for in-phase signals, red for anti-phase signals. The correlometer can be turned off when working with independent signals.
• The inputs of all channels can be configured either as high-impedance, working "through" (10 kOhm - as standard), or as low-impedance (600 Ohm).
• The level of input signals can be adjusted stepwise (+6dB) - by a switch on the board, under the cover, and smoothly - by "slotted" regulators located under the cover of the device.
• In addition to listening, measuring and indicating, the device allows you to detect long pauses or low levels in signals and signal them with an audible signal and blinking of the scale LEDs. This feature can be disabled per channel or completely.
• It is made in the form of one 19-inch 2U block with dimensions of 483x250x88 mm, designed for rack installation.
• Power supply of the device - 220 V ± 10%, 50 Hz.

Single-channel balanced audio signal level indicator MS-11AS

• Dynamic control of the quasi-peak level of a symmetrical audio signal and display it in a visual form using LED emitters of various colors with a large glow area and a wide angle of view.
• Possibility of configuring the input as either high-resistance, working "through", or as low-resistance (600 ohms) using a switch on the rear panel.
• Designed for use in editing and on-air broadcasting and television hardware.

Two-channel balanced audio signal level indicator MS-21AS

• Dynamic control of the quasi-peak level of two independent symmetrical audio signals and display them in a visual form using LED emitters of various colors with a large glow area and a wide angle of view.
• The ability to independently configure the inputs of both channels as either high-impedance, working "through", or as low-resistance (600 Ohm) using switches on the rear panel.
• When used "on the pass" signal transmission without distortion despite the absence or presence of mains power.
• Opportunity smooth adjustment nominal sensitivity, which allows you to accurately set the required sensitivity depending on the type of signal source.
• The protected location of the sensitivity controls is on the rear panel "under the slot".
• Designed for use in editing and on-air broadcasting and television hardware.
• Functionally corresponds to the group II quasi-peak meter according to GOST 21 185-75.
• Metal case, dimensions 483x125x44 (19", 1U).
• Three-wire power supply 220÷230 V.

The company LES-TV (Laboratory Electronic Systems) released the first products in 1992. At present, more than 30,000 units of television equipment have been delivered to users. Over the years, LES switching and control equipment has become the de facto standard for domestic television studios. The company's products work at large television centers and small regional studios in broadcasting, editing and circulation control rooms.

A few reasons why you should contact LES-TV:

When developing new products, the company's specialists use the most modern element base, which ensures the quality and reliability of products.
The company's products are created in close contact with direct consumers: video engineers and operators.
LES equipment is distinguished by ergonomics and modern design;
The company provides its customers with a free 2-year warranty on all manufactured equipment;
The company advises its clients on building studio complexes using our equipment.

DIY do-it-yourself stereo signal peak indication block, simple peak indicator circuit. Peak indicators of audio signals show the fact that the level of the AF signal exceeds a certain predetermined value.

Here is a description of the peak LED indicator based on the CD4093 chip. The domestic analogue of which is K561TL1. The microcircuit contains four logic elements "2I-Not" with the effect of Schmitt triggers. In this circuit, the inputs of each of the elements are interconnected, so the elements work as inverters - Schmitt triggers.

circuit diagram

The output signals of the stereo channels from the ULF output are fed through the capacitors C1 and C2 to the inputs of the elements D1.1 and D1.2, respectively. The inputs of these elements through the resistors R2 and R3 receive a constant bias voltage from the tuning resistor R1.

At the inputs of the logic elements, the DC offset voltage is added to the variable component of the audio signal. The task of the resistor R1 is to set the optimal bias voltage, at which the necessary sensitivity of the indicator will be, that is, this peak threshold is set by this resistor.

Rice. 1. circuit diagram homemade peak indicator.

The state at the outputs of elements D1.1 and D1.2 will change only when this threshold is exceeded, this circuit is set to be converted into logic level pulses, which charge capacitors C3 and C4 through diodes VD1 and VD2. These circuits of diodes VD1, VD2, capacitors C3, C4 and resistors R4, R6 work as detectors.

And the voltage across capacitors C3 and C4 increases. This is especially important, since the peak moment of the input signal may not be long. And the voltage is held in the form of charge by these capacitors because they quickly charge through the diodes and slowly discharge through the resistors.

As soon as the voltage on C3 or C4 reaches the switching threshold of the Schmitt trigger (D1.3 or D1.4, respectively), a logic zero appears at the output of D1.3 or D1.4, which leads to the lighting of the HL1 or HL2 LED. The corresponding LED, or if the stereo signal is well balanced, both LEDs flash and light for at least the time required to discharge C3 or C4 through R4 or R6.

Details and setup

LEDs - any indicator, for example, AL307. Establishment - by adjusting the resistor R1 according to the threshold.

Today, as an indicator of the output signal level for various sound-reproducing equipment, whole electronic devices, which display not only the signal level, but also another useful information. But earlier, dial indicators were used for this, which were a microammeter of the type M476 or M4762. Although I will make a reservation: today, some developers also use dial gauges, although they look much more interesting and differ not only in illumination, but also in design. Getting an old dial indicator now might be a problem. But I had a couple of M4762s from an old Soviet amplifier, and I decided to use them.

On Fig.1 the diagram for one channel is shown. For stereo, we need to assemble two such devices. The signal level indicator is assembled on one transistor T1, any of the series KT315. To increase the sensitivity, a voltage doubling circuit was used on diodes D1 and D2 from the D9 series. The device does not contain scarce radio components, so you can use any that are similar in parameters.

Setting the indicator reading corresponding to the nominal level is carried out by a tuning resistor R2. The integration time of the indicator is 150-350 ms, and the time of the reverse movement of the arrow, determined by the discharge time of the capacitor C5, is 0.5-1.5 s. Capacitor C4 is one for two devices. It is used to smooth out ripples when turned on. In principle, this capacitor can be abandoned.

The device for two audio channels is assembled on a printed circuit board with dimensions of 100X43 mm (See Fig.2). Indicators are mounted here. For easy access to the construction resistors, holes are drilled in the board (not shown in the figure) so that a small screwdriver can pass through to adjust the nominal signal level. However, only this is the setting of this device. You may need to choose the resistor R1 depending on the strength of the output signal of your device. Because on the other side of the board there are pointer indicators, the elements Cl, R1 had to be mounted from the side of the printed conductors. These parts are best taken as small as possible, for example, unpackaged.
Download: Output Level Gauge
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Audio indicator on AN6884

The basis of the design is two microassemblies of the AN6884 (KA2284) type, this is a ready-made LED signal level indicator used to indicate various values ​​\u200b\u200bof the variable signal, to which it remains to connect a few piping components and the LEDs themselves. The scheme of such a device is just shown in the figure below.

You can see photos of the assembled and soldered printed circuit board in the figure below, and you can take its drawing made in the Sprint Layout program from the green link above.

The basis of the design of operational amplifiers - LM324. This circuit uses two quad op-amps to form eight audio frequency slave channels.

Another interesting option circuits of 10 LM324 chips and 40 LEDs. If you assemble two identical designs, you can use it in stereo mode. Supply voltage 12 V, current consumption 2.5A

The range of the sound level indicator (ULF power) should be in the range from 0.5 to 50 watts. A feature of the device is that it does not require an external power supply, it receives its volts from the incoming audio signal.

The basis of the circuit is the LM339 chip, which is a quad comparator. The voltage going to the input of the indicator is doubled with the help of diodes VD1 and VD2 and capacitances C1 and C2, then it follows the 78L05 stabilizer used to power the LM339 op amp and the inverse inputs of the comparators through a voltage divider on resistors R6 and R7. With the help of trimmers R2-R5, each comparator is adjusted to operate at any required level. When the comparator is triggered, the corresponding LED lights up.

LED sound indicator on the A227D chip (K1003PP1)

Basic device settings

Circuit supply voltage: 10-18 V
Input voltage at terminals 3,16,17, max 6.2 V
U input 50-500 mV

Resistance R6 adjust the brightness of the LEDs. Resistor R8 sets the level of lighting of the first LED. R10 - too, only for the last LED. The integrating chain R4,C3 sets the delay time for turning off the LEDs.

The basis of a simple design is the AN6884 chip, which is an almost ready-made signal level indicator. You can also use the transistor version of the device, but you will need a lot of transistors and the effect will be an order of magnitude worse, and the sensitivity is generally lower.

PCB with components and instructions in the package.
This kit will allow you to assemble an UMZCH output power LED indicator. The device allows you to roughly estimate the output power of the amplifier during its operation. And if there are several channels, then identify a possible imbalance in their work. In addition, it will enliven the front panel of your amplifier.

The indicator is made on a specialized LM3915N chip, which is led driver with internal buffer amplifier, comparator and voltage reference. The principle of operation of the microcircuit is based on comparing the value of the input signal with an internal reference voltage source. To expand the input voltage range, the microcircuit is equipped with a programmable divider R5, R6.
Resistor R7 limits the current passing through the LEDs and thus facilitates the thermal operation of the microcircuit.
A peak detector is assembled on transistor VT1, which improves the accuracy of measuring the input signal and prevents the LEDs from flickering at transient signal values.
Resistor R1 can be used to adjust the sensitivity of the indicator within a small range and take into account the ULF load resistance.
Jumper JP1 switches the display mode of the microcircuit - "dot" or "line". In the first case, the value of the input signal is displayed by one LED, in the second, the microcircuit forms a luminous column of LEDs.

Characteristics:
Number of displayed power levels: 10 pcs.;
Rated supply voltage: DC 12 V;
Rated current consumption (in silent mode): 10 mA;
The minimum value of the displayed signal: -27 dB;
The maximum value of the displayed signal: 0 dB;
Input impedance: 100 kOhm;
Assembly complexity: 1 point;
Assembly time: About 1 hour;
Operating temperature range: 0...+45 degrees Celsius;
Relative humidity: 5...95% (non-condensing);
Device dimensions: 56 x 46 x 17 mm;
• total weight set: ~35 g.

Contents of delivery:
printed circuit board;
A set of radio components;
Coil of tubular solder POS-61 (0.5 m);
Instruction manual.

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