PURPOSE: To effset the induced amount at the output terminal of the filter consisting of the input and output transducers of reed screen type electrodes by the differential amplifier, by securing the same level intentionally for the said induced amount.
CONSTITUTION: Surface elastic wave filter 14 consists of input and output transducers 4 and 5 having the reed screen type electrodes each. And the induced amount at the side of the output terminal having a low induction level is increased intentionally to secure the same induction level between output terminals 7a and 7b. In other words, the conduction pattern 20 extended from terminal 7a or 7b at the side where the induction level increase is desired is approximated to conduction pattern 21 extended from input terminal 6a or 6b at the side where the inducton is caused. Thus capacitor 22 is formed between both patterns. Thus the same level is secured for the induction between terminals 7a and 7b, and then the induction of the same level is supplied to differential amplifier 16 to ensure the offset of the induced amount.
WAKATSUKI NOBORU
TOMINAGA HIDEKI
| JPS5342535A | 1978-04-18 |