Victor O Richardson

US Patent:

52049043, Apr 20, 1993

Filed:

Dec 1, 1986

Appl. No.:

6/936459

Inventors:

Robert W. Carver - Snohomish WA
Victor O. Richardson - Seattle WA

Assignee:

Carver Corporation - Lynnwood WA

International Classification:

H04H 500

US Classification:

381 13

Abstract:

A system for increasing the quality of the sound available from a broadcast, frequency modulated, radio frequency, stereophonic signal. Sound quality is promoted by: (1) so switching between available antennas that the signal available from the antenna receiving the incoming signal which is stronger and contains the least multipath distortion is processed into audio output signals, and (2) at least partially blending stereophonically related audio input signals into a monophonic signal if the modulation of the incoming first and second audio signals decreases below a selected threshold value and if: (a) the multipath distortion in the incoming signal reaches or exceeds a preselected threshold value, or (b) the strength of the incoming signal decreases to, or falls below, an also preselected threshold value.

US Patent:

48151416, Mar 21, 1989

Filed:

Dec 2, 1986

Appl. No.:

6/937118

Inventors:

Robert W. Carver - Snohomish WA
Victor O. Richardson - Seattle WA

Assignee:

Carver Corporation - Lynnwood WA

International Classification:

H04B 1500

US Classification:

381 94

Abstract:

A tuner includes circuitry for conditioning an audio signal including (i) a pilot signal canceller, (ii) a noise limiter, (iii) a notch filter, and (iv) a de-emphasizer; as well as an attenuator for RF signals. In an exemplary embodiment, an AM stereo pilot signal canceller utilizes a 25 Hz signal which is added or subtracted from the left and right channels to eliminate the pilot signal. The noise limiter includes a capacitor which is switched into the feedback circuit of an operational amplifier when the input is at a selected level. The diverting of the feedback signal to the capacitor causes the amplifier to saturate thereby removing the noise from the signal. The notch filter includes first and second band pass filters which are centered at a selected frequency, e. g. 10 kHz, for removing a 10 kHz beat note. The passed band is phase shifted so that it is 180 degrees out of phase with the original signal and then added back with the original signal to remove the selected band.