Application of Donald Richman

409 F.2d 269, 56 C.C.P.A. 1083
CourtCourt of Customs and Patent Appeals
DecidedApril 17, 1969
DocketPatent Appeal 8137
StatusPublished
Cited by9 cases

This text of 409 F.2d 269 (Application of Donald Richman) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of Donald Richman, 409 F.2d 269, 56 C.C.P.A. 1083 (ccpa 1969).

Opinion

RICH, Acting Chief Judge.

This appeal is from the decision of the Patent Office Board of Appeals 1 affirming the rejection of claims 23-28 of appellant’s application Ser. No. 223,581, filed September 10, 1962, for reissue of his patent No. 2,954,425, granted September 27, 1960, on an application filed July 15, 1953, for “Phase Detector and Color Killer.”

There are two issues involved. The first issue is whether appellant is entitled to relief under the reissue statute, 35 U.S.C. § 251, 2 or, more specifically, whether he is estopped, under case law, from obtaining the rejected claims by reason of action he took in the prosecution of his original application to obtain the patent for which reissue is sought. The second issue is whether allowance *271 of claims 25 and 28 would result in double patenting in view of appellant’s patent No. 2,848,537, granted August 19, 1958, on an application filed December 31, 1952, for “Highly Noise-Immune Synchronizing System” (herein called the ’537 patent). Both patents issued to the assignee, Hazeltine Research, Inc., which has assented to this application for reissue.

The Invention

The invention relates to control systems for “compatible” color television receivers, that is, those which will receive either monochrome (black-and-white) or color television transmissions.

A color television broadcast signal comprises a complete brightness or monochrome signal modulated on a high-frequency carrier wave and two color-component signals which are phase and amplitude modulated on a lower frequency subearrier wave, which wave in turn is also modulated on the main carrier wave. In the receiver, the brightness signal is demodulated and amplified for application to the brightness control element of the color tube either to produce a monochrome picture when no color signals are being broadcast or to control the brightness of the picture when color signals are being broadcast. The two color-component signals are derived from the received signal in a particular phase relationship and then translated into signals representative of the three primary colors, i. e., red, green and blue, which signals may be applied to corresponding cathodes in the color tube, producing the colors in the picture.

To permit such derivation of the necessary color signals, there is periodically interspersed with the picture signals a color-synchronizing signal comprising short bursts of a relatively few cycles of the unmodulated color subcarrier wave. In the receiver, this so-called synchronizing signal is utilized to control a color reference signal generator to maintain it in synchronism with the transmitted signal. The reference generator produces two reference signals in quadrature, or ninety-degree phase relationship, one of which is desirably in quadrature phase with the synchronizing signal. Those two reference signals are combined with the received color-component signals in a color-difference signal detector to produce the necessary signals for application, through a color combining system, to the color picture tube.

Only when the reference generator signals are in synchronism with the received synchronizing signal will the received color signals be processed in the proper phase relationship to reproduce correctly the colors in the picture. To maintain the reference generator in such synchronism, means are provided to automatically return the reference generator to the desired condition whenever minor variations occur. Thus, appellant provides a first phase-detector circuit which compares the phase of the received synchronizing signal with that generator output signal which is desirably in quadrature phase with it. When the desired quadrature phase condition exists, the phase-detector output signal is zero. Variations of the generator output signal from the exact quadrature phase condition which take place during in-synchronism operation result in the phase detector providing an output voltage and that voltage is applied to a reactance circuit connected to the reference generator in a manner to adjust its frequency in such direction as to restore the desired phase condition.

The application discloses two improvements on the conventional apparatus so far described. First, it provides a system for deactivating the color signal channel of the receiver when a monochrome broadcast is being received instead of a color broadcast. Such a circuit, called a “color killer” circuit, prevents unwanted signals, which would otherwise be translated through the color channels, from reaching the picture tube and there producing a deleterious effect on the monochrome picture being produced at that time.

The second improvement is directed to the circumstance that the previously- *272 mentioned synchronizing circuit for the color reference generator responds only to limited variations from precise synchronism. That characteristic is desirable during in-synchronism operation when a color picture is being produced since it avoids false responses that might be caused by spurious signals which tend to occur, i. e., “noise” signals. However, it prevents the system from automatically reestablishing in-synchronism conditions when larger phase variations occur, as when a new channel is being tuned in. To overcome that difficulty, appellant provides means, operative when the out-of-phase condition of the reference generator exceeds the synchronizing circuit’s normal range, to increase both the effective pull-in range and the rate of pull-in. Such operation is known as “two mode synchronization.”

To provide the aforementioned features, appellant provides a second phase-detector circuit which responds to the relationship of the synchronizing signal and the second output signal of the generator, that is, the one which is desirably in phase with the synchronizing signal. This second phase detector provides an output voltage which is of a maximum amplitude when the compared signals are in the desired phase relationship but is of a lesser value, such as substantially zero, when the two signals are out of phase by an excessive amount and also when no color-synchronizing signal is received. The maximum signal resulting from satisfactory color-reproducing conditions operates a circuit to maintain in operation an amplifier supplying the col- or component signals to the color-difference signal detector. If a color-synchronizing signal is not received, the output of the second phase detector falls to substantially zero and the amplifier for the color-difference signals is thereby disabled or rendered inoperative to transmit such signals. The signal output from the second phase detector will likewise drop from its maximum value to substantially zero when a color-synchronizing signal is being received if the reference generator is so far out of synchronism that the regular synchronizing circuit does not provide an adequate control signal to bring the reference generator back into synchronism. In one form of appellant’s invention, the amplifier for the color-component signals provides, when disabled, a signal which increases the gain or amplification of two amplifiers which amplify the respective input signals to the phase-detector circuits.

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Bluebook (online)
409 F.2d 269, 56 C.C.P.A. 1083, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-donald-richman-ccpa-1969.