Digitally-driven sine/cosine generator and modulator
US4524326A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 22, 1982 |
| Grant date | Jun 18, 1985 |
| Priority date | — |
| Expiry date | Jul 22, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06J1/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electrical circuit and method for multiplying an analog input signal by a sinusoidal function having an instantaneous phase specified by a number signaled in binary format. As a sine wave generator, the binary number is supplied by a counter clocked at a multiple of the desired sine wave frequency. The most significant bit of the counter modulates the polarity of or actually constitutes the analog input signal which is then fed to a numerically-controlled attenuator driven by the less significant binary counter outputs. The attenuator has selectively switched resistors with values specifying a sine table of attenuation from 0 to 90 degrees. A particular resistor is selected by an analog multiplexer having paired complementary outputs so that over the range of less significant bit values, a full 180 degrees of the sinusoid is generated. As a sine wave modulator, the polarity of the analog input signal is modulated in a balanced modulator by the most significant bit of the counter, and the balanced modulator output is used as the input to the attenuator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.