Abstract: A quadrature amplitude modulation (QAM) communication system is provided in which data can be communicated in any one of a plurality of QAM modes, such as 16-QAM, 32-QAM, and 64-QAM. A receiver detects the particular QAM mode transmitted on a trial and error basis, by attempting to decode the received data using different QAM modes until a synchronization condition is detected. The synchronization condition can require that a plurality of different synchronization tests be met. In a specific embodiment, a first synchronization test is met when a renormalization rate of a trellis decoder is below a threshold value. A second synchronization test is met when a first synchronization word is detected in the received data. A third and final synchronization test is met when a second synchronization word is detected in the received data. In order to reduce the cost of the receiver, most of the QAM mode dependent components are implemented using look-up tables stored in PROMs.

Abstract: An interleaver processes information in a pseudorandom order to provide pseudorandom interleaved data for communication to a deinterleaver. The pseudorandom interleaved data is processed at the deinterleaver in a pseudorandom order corresponding to that used at the interleaver means, to recover the original information. The pseudorandom processing at the deinterleaver is synchronized with the pseudorandom processing at the interleaver on a trial and error basis. In one embodiment, full synchronization occurs when a Viterbi decoder receiving data from the deinterleaver has a renormalization rate within a designated threshold and when enough synchronization words are detected in data output from the deinterleaver to meet a predetermined criterion. In another embodiment, a timer is used to initiate a new starting address for the pseudorandom processing at the deinterleaver during successive time intervals.

Abstract: A fluid supply system (10) for delivering a supply fluid to a washdown facility and for automatically diverting contaminated run-off to the sewer. The fluid supply system (10) includes a demand valve (13) connected in series in a supply line (11). The demand valve (13) is attached to a control line (14) which leads control fluid to a diversion valve (15) located in a sump (16). The demand valve (13) can operate either under upstream or downstream control to activate the diversion (15). In order to avoid inadvertent operation of the diversion valve the demand valve (13) includes a control valve member (33) and a pressure plate (32) which permits a small flow of fluid along the line such as may be experienced by a dripping tap. When the flow along the supply line exceeds a predetermined level the demand valve operates to divert control fluid to the diversion valve (15) to fill a variable volume chamber (48) and thereby unseat a diversion valve member (45) to open the diversion valve (15).

Abstract: A method of testing the integrity of a package seal (14) provided between a container portion (11) and a lid portion (12), includes the steps of: initially reducing the pressure acting on the outer surface of the container portion to cause the lid portion to bow inwardly to a position of substantially maximum concavity while maintaining the ullage volume within the package substantially constant; further reducing the pressure acting on the outer surface of the container portion to distend the container portion for increasing the volume of the ullage space; and sensing for a change in position of the distended container wall.