FM Video recording and reproducing system
US4435734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1981 |
| Grant date | Mar 6, 1984 |
| Priority date | — |
| Expiry date | Nov 12, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
High resolution video signals of bandwidth up to 25 mHz are recorded magnetically or optically, or are transmitted on a communications channel carrier with superior fidelity by using novel electronic circuit system including implementations of an FM modulator, writing amplifier, and wideband discriminator which enable coding and decoding with high accuracy, low noise, and low interference. The video signals are used to directly modulate a square wave carrier using an FM technique employing a very low center frequency-to-bandwidth ratio without need for subsequent frequency translations. A writing amplifier provides gain needed for saturated recording with unique provisions to balance transition amplitudes for minimum second harmonic distortion without affecting the primary phasing of transitions. A novel multiwinding inductor and pulse discriminator implementation is capable of demodulating the very wide deviation FM signal with good cancellation of the second harmonic and fundamental FM carrier spectrums. Novel electronic circuit techniques are disclosed to provide high levels of performance with simple implementations of the electronic hardware.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.