Patent · US Expired

Detection circuit for pilot tones for tracking control in the case of magnetic-tape recordings

US5949606A · kind A · utility

3Cited by

5References

8Claims

0Family size

Assignee

Deutsche Thomson-Brandt GmbH · DE

Inventors

Juergen Kaaden · Villingen, DE
Sabine Roth · Berlin, DE
Heinrich Schemmann · Villingen-Schwenningen, DE

Key dates

Filing date	Mar 10, 1997
Grant date	Sep 7, 1999
Priority date	—
Expiry date	Mar 10, 2017

Classification

Technology area (CPC G)Physics
CPC primaryG11B5/5921
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

In the case of various recording systems based on the helical-scan method for magnetic tapes, a pilot-tone principle is used for tracking control, generally using two pilot tones which are recorded on the helical tracks respectively in series of four: pilot tone F1, no pilot tone, pilot tone F2, no pilot tone. Known methods for determining the pilot-tone amplitudes use narrow-banded band filters, a control signal being generated by forming the difference between the amplitudes. On account of the weak pilot tones, this requires very narrow-banded filters with good dynamic properties. According to the invention, a quadrature mixing has the effect of converting the two pilot tones into the baseband, whereby the filtering is performed in the low-pass range and a control signal can be derived from the difference between the pilot-tone amplitudes thus determined.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.