MV 240 digital – The future of measurement microphones

NEW MV 240 digital – The future of measurement microphones

1/2“ Microphone Preamplifier with integrated ADC

The innovative MV 240 digital is an all-in-one new development, which differs in every respect from all commercially available analog-digital solutions in terms of design, functionality  and quality.

Outstanding features are, e.g:

• 32 bit data transmission
• Digital transmission of fixed calibrated sound pressure levels
• Full dynamics of the newly developed low noise ½ " Capsule
• With ¼"capsule -max.160dB sound pressure level
• dynamic range – 32 bit range – 186dB
• no separate power supply necessary

With the specially developed high-end, low noise capsule and the new, integrated electronics (among others, with integrated AD converter) the MV 240 expands the circle of potential users considerably.

Exactness and simplified operation make it possible to optimize existing and find new, cost-saving applications (e.g. industry, environment, R&D, occupational health and safety, Study and training sector).

Existing disadvantages of previous AD solutions could be overcome, e.g:

• time-consuming and personnel-intensive installation and operation,
• Errors due to complicated coordination of several electronic and software components,
• handling the electrical voltage as a coupler by the user,
• Measurable / audible USB artifacts,
• Insufficient sensitivity or limited frequency range, etc.

The MV 240 thus offers the possibility of solving all the above problems with just one device, replacing 2 analogue microphones, 2 analogue front end channels and part of the digital signal processing in a cost-saving way.

 Customer benefits of the new MV 240:

Only one measuring range for the entire dynamic range, i.e. no range switching necessary,

• direct digital sound pressure conversion (with exact sensor-ADU adjustment to exclude common sources of error),
• Sampling frequency up to 192kHz is supported,
• no measurable/audible USB artifacts, USB class compatible (USB 2/3), no additional driver necessary,
• User independence from special manufacturer software, possibility of using commercially free available measurement software,
• internally generated capsule polarization voltage 200V,
• Minimal inherent noise due to optimum adaptation of the measuring capsule to the AD converter,
• Compatible with all common OS, such as Windows® (XP,Vista, 7, 8, 8.1, 10),Linux, Mac OS®, ioS®),
• Electrical voltage in the system is irrelevant to the user due to direct digital sound pressure conversion.

      (Direct Digital Sound Pressure Transformation/DDST, based on a new definition:  1µPa ≙ Integer value 1 in LSB.)

Another major advantage is a test generator integrated in the microphone, which checks both the complete transmission and evaluation of a 32-bit data stream from the microphone via the interface to the measurement software on the PC, as well as a further integrated test generator, which generates a signal corresponding to the sound pressure of 1 Pascal to show the reference point in the respective measurement software (internal electrical voltage in the system is irrelevant, which increases measurement reliability).

Specification 

• USB interface (4-pin LEMO®)
• power supply via USB
• capsule polarisation voltage:internally generated (200 V)
• 1 Hz to 80 kHz / 7 dBA to 160 dB

The 1/2“ measurement microphone pre-amplifier type MV 240 combines a high-impedance transducer with an analog-to-digital converter/ADC.

The AD conversion takes place in 2 level ranges (24bit each). An integrated processor combines both level ranges to a single-channel USB output signal/32bit (corresponds to already calibrated sound pressure values).

One channel of a 24 bit analog-to-digital converter converts the lower level range of the capsule signal and the other channel the upper level range. A following processor combines these two level ranges to the one-channel 32 bit output signal.

The output signal of the capsule is optimally adjusted to the ADC`s dynamic range by an impedance converter and a preamplifier with a very low noise level and THD.

The pre-amplifier converts sound pressure levels from 7 dB to 160 dB, a frequency range up to 80 kHz and generates internally a switchable 200 V polarisation voltage for the microphone capsule. For the use of the MV 240 no special hardware driver is necessary because it is detected automatically by different operating systems like Windows®, MacOS® or Linux.

The MV 240 is powered by the USB interface and generates internally
200 V polarisation voltage for the measurement microphone capsule that can be switched off when using electret measurement microphone cap.

www.microtechgefell.de