Computer Aided Engineering & Measurement Systems

Precision Stroboscope Features & Capabilities • Precision Constant Duty Cycle Stroboscope • Wide operating rate 0Hz - 10kHz • Fine Frequency Resolution of 0.01Hz • SuperFlux High Power White LED technology • Collimating Lens with 45° Beam Width • Long Flash LED Lifetime 50K - 100K Hours • Wide Range Sync Capability 0.5V - 300V • Fully Programmable via RS-232 • Four (4) Operating Modes • Four (4) Parameter Display Modes • 6 Digit 7-Segment Numeric Display • Backlit Status Indicators • Win32 Application Software • High Capacity Lithium Ion Battery • Portable Hand Held Battery Operated • Small & Lightweight Size Chassis • Built-in Universal Charger 85VAC-265VAC LS310 - Precision High Speed Stroboscope The LS310 is a portable battery operated hand-held instrument roughly the same size as a flashlight. Shaped as an octagon, it is 2 inches across and 7 inches long weighing less than one pound. The LS310 utilizes a rechargeable Lithium Ion battery and features a universal 85-265VAC built-in charger.

The LS310 utilizes the latest in high power LED technology with a 7 Watt SuperFlux high efficiency multi LED and collimating lens. The intensity is very bright with each flash producing nearly 200 lumens of white light. A strobe based on LED technology has several important advantages over traditional Xeon based strobes: (1) Flash duration can be programmed and controlled precisely over an extremely large range from seconds down to sub-micro seconds, (2) the life of the LED is virtually unlimited, (3) programmable flash intensity, and (4) lower cost low voltage drive circuitry. The highly controllable LED flash duration enables constant duty cycle operation vs. frequency which is virtually impossible for Xeon based strobes.

The LS310 offers a comprehensive array of features to examine surface vibrations of transducer diaphragms, among other general purpose strobe applications. A stroboscope allows a moving or vibrating object to be viewed as if it was stationary. By flashing a short burst of light at the same time during each periodic vibration of the driver, the diaphragm appears stationary. This allows changes in the surface to be observed at any frequency of interest.

While common acoustic frequency response testing of drivers can quickly show peaks, nulls, or resonances in the response, it does not indicate the source of the problem. A stroboscope can be invaluable for this purpose often showing exactly the mechanical cause of the response defect.

Typically the driver is swept using a sine wave stimulus across a frequency range. The stroboscope is synchronized to the same signal, flashing at exactly the same frequency and at the same phase of each period.

A variety of motional problems can be quickly observed including: resonance deformations in the surround, resonance modes in the spider, flexing of dust caps, improper or loose glue seams, standing waves in lead wires, and rocking motions of the cone. LS310 testing a woofer

LinearX Systems Inc • 9500 SW Tualatin-Sherwood Rd. • Tualatin, OR 97062-8586 USA • TEL: (503) 612-9565 • FAX: (503) 612-9344 www.linearx.com • [email protected] Description The LS310 contains (4) push-button switches, (2) display windows, (3) 3.5mm stereo jacks for connection, and an IEC-C8 2-pin AC power adapter inlet. The four push-buttons control: Up, Down, Mode, and Display. The Up/Down switches change frequency or phase, while the Mode switch selects various operating modes, and the Display switch controls which numeric parameter is displayed in the readout window. Operating Modes

■ Manual In this mode the external sync input is not used or required. The flash frequency of the strobe is controlled solely by the Up/ Down buttons. This mode can be very useful for general work, or for determining the frequency of a moving/rotating object, driver, motor, fan, etc.

■ Sync - Frequency In this mode the external sync input is used to provide the base frequency of the strobe. However the actual strobe frequency can be offset by a user defined value. For example, if a frequency offset of +1.00Hz is used the strobe will flash at a rate 1Hz higher than the sync frequency. As the signal is swept across frequency, the strobe will always flash 1Hz higher than the sweep frequency. This allows the user to view the diaphragm in a 1Hz motion at any driven stimulus frequency. A very useful mode.

■ Sync - Phase In this mode the external sync input is used to provide the exact frequency of the strobe. However the actual phase position of the flash can be offset/stepped through the entire 360 degree period. This mode can be very useful in examining the motional behavior across the entire periodic cycle of the driver. Resolution / step size is adjustable from 1 degree to 45 degrees.

■ Flashlight In this mode the strobe flashes at a high rate to provide general illumination. This mode is useful when you wish to illuminate the object without any synchronous flashing. The actual frequency can be changed thus providing a secondary manual mode.

Display Modes

■ Flash/Sec (Hz) This mode displays the actual strobe frequency in flashes per second, or Hertz.

■ Flash/Min (RPM) This mode displays the actual strobe frequency in flashes per minute, or RPM.

■ Frequency Offset (Hz) This mode displays the strobe frequency offset in flashes per second, or Hertz.

■ Phase Offset (Deg) This mode displays the strobe phase offset in degrees.

Connections

■ Sync Input The LS310 can sync to any periodic signal ranging from 0.5VRMS to 300VRMS. The LS310 employs patented circuitry which adjusts itself to the incoming signal strength instantaneously. The Sync input can be attached directly to the driver speaker terminals to obtain the sync.

■ Trigger Output The trigger output by default provides a pulse identical to the flash pulse rate of the strobe. Future enhancments provide for other special trigger applications and options as well.

■ RS-232 Interface The RS-232 interface allows connection to a PC for update of firmware and modification of control parameters through the Win32 application software, or for custom programming by the user.. High Precision Phase Control Both of the sync modes require that an external signal be applied to the Sync Input. In the Sync-Phase mode, the LS310 locks on to the external input frequency precisely, and then flashes at various phase offsets within the 360 period.

The default phase resolution is 10 degrees. For each period of 360 degrees this means there will be 36 possible steps. The strobe will flash for a duration of 10 degrees or 1/36 of each period. Where in the period the strobe flashes is controlled by this phase offset.

The sequence of scope photos on the right shows the phase offset stepped through 10, 20, 30, 40, and 50 degree offsets. The Yellow trace is the sync input signal and the Green trace is the trigger output. The strobe flashes during the positive pulse.

For electroacoustic work the Sync-Phase mode will produce a visual display of the moving diaphragm frozen at a particular position. As the phase offset is changed, the diaphragm will be frozen at different positions of its travel through the entire period. As the frequency is changed the phase offset position is always maintained.

The phase resolution is in effect during all operating modes. If the resolution is set to 10 degrees, then the flash duty cycle is 10/360 or 1/36 or 2.78%. Thus the continuous light power of the strobe is reduced by a factor of 36. The user can change the phase resolution from 1 degree to 45 degrees, thus providing highly different resolutions, number of steps, flash duty cycle, and equivalent light intensity.

There is an inherent trade-off between the phase resolution and flash intensity. While it is desirable to have the smallest possible resolution to provide a clear frozen visual image, it also reduces the effective power proportionally. For example, a phase resolution of 1 degree produces extremely narrow flashes but also reduces the flash power to 1/ 360 or 0.278% duty cycle. Using a resolution of 10 degrees generally provides the best trade-off between the competing requirements.

Windows Application Software The LS310 has additional parameters which can be controlled through the provided Windows application. The LS310 is fully programmable via RS- 232 commands. The user can control the strobe remotely through custom RS-232 software or the Win32 DLL interface. Specifications

■ Functions Flash Power Full, 1/2, 1/4, 1/8, 1/16 power Operating Modes Manual, Sync-Freq, Sync-Phase, Flashlight Display Modes Flashes/Sec (Hz), Flashes/Min (RPM), Freq Offset, Phase Offset Precision Phase Resolution 1, 2, 3, 5, 7½, 10, 15, 20, 30, 45 degrees Strobescope Frequency Resolution 0.01Hz

■ Optical ■ Software DN UP Light Source 7W SuperFlux LED Win32 Application

Beam Width 45 Degrees DLL programming interface DISPLAY MODE Flash Intensity 200 Lumens RS-232 comand protocol

Flash Pulse Width >250mSec to <300nSec OFF ON Color Grade White ■ Mechanical 5500K Length 7.1 Inches (180mm) Lifetime 50K-100K Hours Width 2 Inches (50mm) MANUAL Height 2 Inches (50mm) SYNC-FRQ ■ Electrical Weight 12oz (300g) SYNC-PHS

Sync Input 3.5mm Jack Finish Black Anodized FLASHLIGHT Sync Voltage 0.5VAC to 300VAC Material Aluminum CHARGING Sync Frequency Range DC to > 10kHz Case Black Plastic w/Foam Sync Input Impedance >5K Ohms, self adjusting FLASH/SEC RS-232 Interface 3.5mm Jack ■ Cables FLASH / MIN RS-232 Protocol TX/RX 9600 Baud, 8/1/N (2) 2M 3.5mm to BNC FREQ OFS

Trigger Output 3.5mm Jack (1) 2M 3.5mm to DB-9F PHASE OFS Trigger Level Bipolar ±5V, TTL, LVTTL (1) 2M IEC-C7 to USA Microprocessor 60MHz, ARM-7, 32 Bit MCU Operating Time 10-12 Hours typ Charge Time 3-4 Hours Universal Charger 5W, 85-265VAC, 50/60Hz Battery Lithium Ion 18650, 2.4AHr/3.6V

SYNC RS232 TRIG

INPUT INTERFACE OUTPUT

CHARGER 85-265VAC 50/60HZ 5W

Visit our web site or contact the factory for a list of International Dealers. LINEARX SYSTEMS INC All specifications subject to change without notice. 9500 SW Tualatin-Sherwood Rd © 2007 All Rights Reserved. Tualatin, OR 97062-8586 USA Printed in the U.S.A. Tel: 503-612-9565 Fax: 503-612-9344 MAR-15-2007 www.linearx.com [email protected]