Television broadcasting signal receiving tuner

Abstract

The invention provides a television broadcasting signal receiving tuner which is impossible to lower the basic property by corresponding to a PAL mode and SECAM-L mode on a VHF low-frequency band. A television broadcasting signal receiving tuner (1) which can receive a PAL mode and SECAM-L mode television broadcasting signal is provided with a first tuning circuit (11), a second tuning circuit (12) and a RF tuning circuit (4), wherein the RF tuning circuit (4) has a coupling inductor (L5) for adjusting the coupling degree between the first and second tuning circuits (11) and (12). Under the action of the RF tuning circuit (4), the coupling degree of the coupling inductor when the SECAM-L mode television broadcasting signal on the VHF low-frequency band is received is smaller than the coupling degree of the coupling inductor when the PAL mode television broadcasting signal is received.

Description

technical field [0001] The invention relates to a TV broadcast signal receiving tuner capable of receiving TV broadcast signals in PAL mode and SECAM mode. Background technique [0002] In Europe, the PAL method and the SECAM-L method are adopted as the TV broadcasting method, and tuners capable of receiving the TV broadcasting signals of the PAL method and the SECAM(L) method have been developed. Conventionally, a tuner having a VHF high band and VHF low band switching circuit configuration is known as a TV broadcast signal receiving tuner compatible with the PAL system and the SECAM (L) system (for example, refer to Patent Document 1). [0003] like Image 6 It shows that this TV broadcast signal receiving tuner 21 has an antenna tuning circuit 22, an RF amplifier circuit 23, an RF tuning circuit 24, a VHF mixing circuit 25, a VHF local oscillator circuit 26, and an IF tuning circuit 27. By switching the RF tuning circuit 24 The circuit structure can receive TV broadcasti...

AI Technical Summary

Problems solved by technology

[0013] The above-mentioned TV broadcast signal receiving tuner 21, such as Figure 7 As shown in (a), it is designed to give priority to the basic performance of the PAL method and attenuate the upper adjacent channel interference signal UD, so as Figure 7 As shown in (b), when receiving the SECAM-L TV broadcast signal, the lower adjacent channel interference signal UD cannot be sufficiently attenuated

Therefore, the TV broadcast signal receiving tuner 21 does not have room for basic performances such as EMC resistance, and it is difficult to absorb variations in basic performances during mass production.

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