Abstract: A high frequency apparatus includes an input terminal 21, a high frequency filter 22 to which a signal input into the input terminal 21 is supplied, a mixer 24, one input of which an output signal of the high frequency filter 22 is supplied to and an other input of which an output signal of a local oscillator 23 is supplied to, an intermediate frequency filter 25 to which an output signal of the mixer 24 is supplied, an output terminal 27 to which an output signal of the intermediate frequency filter 25 is supplied, and an electronic switch 30. The electronic switch is provided in the vicinity of the intermediate frequency filter 25, for making a passband characteristic of the intermediate frequency filter 25 substantially flat by closing both contacts, wherein opening and closing of the electronic switch 30 is controlled externally. Accordingly, the adjusting error of the high frequency filter can be reduced.

Abstract: A manufacturing method comprises the steps of changing an identification number of each electronic device 15 into a bar code and adhering it to an electronic component 18, reading the bar code 12a, and writing information of the bar code in a memory of the electronic device 15. All the steps for writing identification numbers are automated so that human errors in setting the identification numbers by an operator can be prevented.

Abstract: The present invention involves a method of writing an identification number of a CATV receiving apparatus and intends to achieve a rapid write operation and reduction in the capacity of a control program. A microcomputer (7) is reset in a first step (15) and a write pin (13) of a memory write unit (10) is brought into direct engagement with an input/output terminal (8a) of a memory (8) in a second step (16). Subsequently, in a third step (17), a preset identification number of the CATV receiving apparatus is written into the memory (8) through the write pin (13), so that the microcomputer (7) need not start any identification number write program and a rapid write operation can be ensured. No identification number write program is required for the microcomputer (7) and therefore, reduction in the capacity of the control program can be realized.