Air Traffic Control Tone Notching


The DSP-8200e Card Cage Family consists of a 5-1/4 x 19 inch rack mounted card cage chassis, 12 plug-in DSP modules, a Control Module, and two redundant Power Supply modules. The card cage chassis is built around Euro rack standards. Access to modules and cabling is from the rear side of the chassis. Status LEDs are on the chassis front panel and duplicated on each module.

Each DSP module has signal processing for two audio channels. Overload and Normal Level indicators are provided for each channel. A Heartbeat Status LED flashes at a one-second interval to show proper operation. The input and output audio interface are balanced 600 ohm lines with audio transformers. A watchdog timer monitors circuit operation and will reset each the module in the event of program failure. To insure that audio is never interrupted, each audio channel is passively relay bypassed when the unit is unpowered.

The Control Module and Power Supply 

The control module monitors each DSP module for proper operation. Through the use of a computer interface, the Control Module provides fault detection, diagnostics and reprogrammability.

In the event of a DSP module failure, an audible alarm will alert the operator that a problem has occurred. To assist in identifying the failed module, the heartbeat indicator will blink at 4 times the normal rate. In addition, the BNC connector will go into fault position.

The DSP-8200e includes a logging feature that records tone incidences including time, date , frequency and duration.

A relay switch closure output (BNC connector) is provided which will indicate if power has been lost to the DSP-8200e as well as an individual module failure. This output may be configured (via shorting jumper) as either normally open or normally closed.

Operators can connect the DSP-8200e to a standard terminal program using a RS-232 or USB cable. One such common terminal program that is included in all Windows Operating Systems since Windows 95 is HyperTerminal.

Each power supply module is fully capable of supplying all of the necessary power to operate all the modules. If one of the power supply modules fail, the card cage will continue to operate. Each power supply module is supplied with a 5x20mm DIN 1A fuse. The power supply modules can be configured for either 115V or 230V operation.

Other Applications for the DSP-8200e Card Cage System

Our DSP-8200e Tone Suppression & Noise Reduction System is designed to protect radio operators from inadvertent signaling or test tones and to reduce noise in radio communications.

Many other signal processing applications are possible with the DSP-8200 family. These could include automatic level controls, limiters, multichannel diagnostic or monitoring systems, signal routing systems; essentially applications where multichannel signal processing is desired in the audio frequency range.

Ground-to-Ground Tone Suppression Mode

The DSP-8200e offers a Ground-to-Ground tone suppression mode that addresses the unique challenges of Ground-to-Ground circuits.

In this mode, we specifically notch certain frequencies that are the most common test tones while passing the signaling tones. This greatly reduces the chance of a "tone incidence" while using circuits where no solution was previously available.

DSP-8200s2 8200S2 UPDATE

The DSP-8200s2 is a single channel tone notching (suppression) instrument intended for air traffic applications. It typically is used in two types of voice communication systems:

  • Voice Switching and Control System (VSCS)

  • Tower Audio and Control (TAC)

The DSP-8200s2 uses a 32 bit floating point DSP to execute a unique tone suppression algorithm developed by Danville. This algorithm has been used to prevent tone incidences in air traffic control systems since 1998.

The audio input and output amplifiers are transformer coupled. The input gain and output level are adjustable in 1 dB steps. This allows the DSP-8200s2 to perform level conversion as necessary. The circuits are automatically loopbacked (with optional attenuation) using relays when power is removed from the DSP-8200s2.