A bias current is generated for an unbalanced differential pair that is proportional to the transconductance gain of the differential pair. The awning system includes a peripheral frame covered substantially entirely by a fabric valance member 32. The carrier profiled parts are used to ensure the connection to the adjacently arranged frame sides in such a way that they can be displaced and fixed in relation to each other. The fixing portion stretches sideward and forms a pair of locating projections. The bubble is expandable to open the package in response to bursting detonator 18.