High-speed Recording System


Audio recording has come a long way since the first known recording of a human voice was carried out in the 1870s, on a tinfoil cylinder phonograph. In the present times, the Audio High Speed Recording SystemRecording industry uses high voltage, multi-channel, multiple-speed recording systems with variable gain levels. Designing such a system poses a severe engineering challenge; as does the additional challenge of maintaining high SNR (Signal-to-Noise Ratio) for all recording speeds. This case study showcases Mistral’s ability to design and develop such a high-speed recording system.

The Customer

A leading high technology company in US, focusing on manufacture and sales of recording, CD-R, cassette duplication, telephony and audio logging equipment, approached Mistral to provide a solution for high-speed audio tape recording.

The Requirement

The customer requirement was to design a PC based 4-channel audio recording system compatible with different slave recorders.

Solution Provided

Audio recording applications require a large amount of memory and low latency data transfers to obtain high quality audio. Mistral came up with a novel solution: a PC-based, high-speed, PCI compatible card featuring 4-channels, 14-bit data conversion resolution, up to 128X speeds, and a Windows-based GUI. 

  • On-board sharp cut-off low-pass filter banks to keep minimum THD (Total Harmonic Distortion)
  • On-board 32K memory for continuous data streaming from system memory
  • Auto-filter bank selection, based on the speed
  • Multiple recording speeds: 32X, 40X, 64X, 80X, 100X and 128X (where X is the base audio recording speed, viz. 44.1 KHz)
  • 4 Audio channels
  • Variable gain levels (-3dB to 23dB)
  • Compatible with up to 20 slave systems
  • 60 dB SNR for all recording speeds
  • PC-based hardware with Windows compatible software
  • Cue tone generation with software adjustments for level, frequency and duration
  • Configurable counter to record number of duplications
  • Remote start/stop control for slaves
  • A hardware custom logic controlling critical timing parameters.

Read More to know how we implemented continuous data streaming, noise suppression and SNR in the system