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US 6,307,600 B1Granted
Tuning with diode detector
AssigneeU.S. Philips Corporation
InventorMeye Wink
Life of this patent
Estimating the term…
Abstract
A tuner, for example, for a television receiver, includes a UHF and a VHF section and a mixer oscillator stage. It is known that the VHF frequency band has to be split in at least two parts to handle the VHF signals. To that end, the mixer oscillator stage uses two separate VHF oscillators and a detector to switch tuned parts of the VHF section. In this way, the performance of the tuner is improved.
Claims5
A tuner for tuning an input signal, said tuner comprising;
- an input for receiving the input signal:
- a UHF section coupled to the input for handling UHF signals, and a VHF section coupled to the input for handling VHF signals;
- and
- a mixer oscillator stage coupled to outputs of the UHF section and the VHF section, said mixer oscillator stage comprising UHF oscillation means with a UHF tuning circuit and VHF oscillation means with VHF tuning means, an output of said mixer oscillator stage being coupled to an output of the tuner, characterized in that the VHF oscillation means comprises a first and a second VHF oscillator, said VHF tuning means comprises a first and a second VHF tuning circuit coupled, respectively, to said first and second VHF oscillators, for providing a first and a second VHF frequency range, respectively, and the tuner further comprises detecting means for detecting which of said first and second VHF oscillators is operating, the detecting means supplying a switching signal to switchable elements in the VHF section.
1 more element
Mixer oscillator stage for use in a tuner for tuning an input signal, said tuner comprising:
- an input for receiving the input signal;
- a UHF section coupled to the input for handling UHF signals, and a VHF section coupled to the input for handling VHF signals;
- and
- said mixer oscillator stage coupled to outputs of the UHF section and the VHF section, said mixer oscillator stage comprising UHF oscillation means with a UHF tuning circuit and VHF oscillation means with VHF tuning means, an output of said mixer oscillator stage being coupled to an output of the tuner. characterized in that the VHF oscillation means comprises a first and a second VHF oscillator, said VHF tuning means comprises a first and a second VHF tuning circuit coupled, respectively, to said first and second VHF oscillators, for providing a first and a second VHF frequency range, respectively, and the tuner further comprises detecting means for detecting which of said first and second VHF oscillators is operating, the detecting means supplying a switching signal to switchable elements in the VHF section.
1 more element
Dependencies are inferred from the claim text.