General Research of Electronics, Inc.

Kiyoshi Wakui

Nobuaki Yokoyama

Kazuo Kawai

Sadanori Shitara

With the objective of providing a scanning receiver capable of capturing a target radio wave in an extremely short period of time by use of a simple constituting means, a plurality of wide frequency division bands in which a full frequency range is divided into predetermined frequency ranges are set and the field intensities of received radio waves are retrieved using the output of an intermediate frequency amplifier circuit over the set wide frequency division bands in order. Further, when a received radio wave having a field intensity greater than or equal to a prescribed level is obtained upon the above retrieval, receive frequencies are swept from one end of each of the wide frequency division bands to the other end thereof. When a target radio wave can be captured upon the above sweeping, transition to the operation of receiving the target radio wave is performed. When the target radio wave is not obtained, the retrieval of field intensities of received radio waves and the sweeping of receive frequencies following the retrieval are performed over the non-retrieved wide frequency division bands in a sequential order to capture the corresponding target radio wave.

Scanning receiver

A frequency scanning receiver minimizes the time needed for setting the frequency of a phased lock loop of a first local oscillator. The frequency scanning receiver is configured so that when the reference frequency of the PLL of the first local oscillator has been set at a high frequency, and the frequency error is less than the second IF, the frequency error is controlled to be zero by the control circuit switching the frequency of a second local oscillator or third local oscillator to an appropriate frequency using an output of a frequency discriminator.

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Tokyo, Japan

Kiyoshi Wakui