Time-period modulation transmission system
US4475244A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Feb 10, 1983 |
| Grant date | Oct 2, 1984 |
| Priority date | — |
| Expiry date | Feb 10, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/06
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for time-period modulating (TPM) a subcarrier in accordance with the amplitude of an input signal includes generating a ramp signal of constant slope, comparing the ramp signal with the input signal, and resetting the ramp signal when the ramp signal reaches the input signal. Each time the ramp signal is reset, a clock pulse is counted. These clock pulses are counted in cyclic groups of N. After each clock pulse is counted, the then attained count is converted to a value of a sinusoid about some reference. The values for each of N counts define one sinusoidal cycle of the modulated subcarrier. Converting these values to voltage levels produces a sinusoidal stepwave which has a period linearly proportional to the amplitude of the input signal at the time. At a receiver, demodulation of the signal is achieved by squaring each cycle of the TPM signal, and during a predetermined half cycle of each squarewave cycle, generating a ramp signal of constant slope which reaches a voltage level in one half cycle linearly proportional to the period of the TPM cycle. The voltage level attained in each demodulating half cycle is sampled and held until the next demodulating half cycle. In…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.