Patent ID: 7595845

Claim:
A television switch module that switches output lines of television high frequency signals, comprising: first and second input lines that respectively input television high frequency signals; first and second output lines that output signals which are after being amplified; first and second amplifiers inserted in the respective input lines for respectively amplifying input signals; a brancher disposed in at least one line at an input or an output of the first or the second amplifier for branching the input line; a relay switch disposed in a further line different from the one line with the brancher that switches either to the one line with the brancher or to the further line branched by the brancher; a relay switch controller that switches the relay switch based on an operation from outside; and a power supply controller that controls a power supply to the respective amplifiers, and stops the power supply to an amplifier inserted in an unused input line, wherein the brancher is disposed at each of the outputs of the first and second amplifiers inserted in the respective input lines to form two units, the relay switch is disposed in each of the lines to form a first relay switch and a second relay switch, and each of the relay switches has relay switch contacts, to which one branch line by the brancher disposed in one line and one branch line by the brancher disposed in the other line are respectively connected, and also has a relay common contact, the common contact being connected to each of the output lines, the power supply to the first and second amplifiers being provided from the output lines by way of the contacts of the relay switches, and an active current stabilizer being added to an amplifier output transistor of the amplifier, wherein the amplifier comprises: a grounded-emitter signal amplifying transistor having a base, to which a signal is input, and a collector connected to a power supply Vcc through a load resistance, the collector being a signal output terminal; and the current stabilizer is added between the collector and the base of the transistor, to keep constant a current flowing through the load resistance so as to keep constant a collector voltage Vc of the transistor, and wherein the current stabilizer is formed of a unit of at least two transistors, and has a configuration which works to cause a reference voltage for the current stabilizer, as obtained by a resistance voltage division of the power supply Vcc, to be equal to the collector voltage Vc of the signal amplifying transistor.