JPH0593135U - Receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] In a diversity receiver, always obtain the best reception strength and simplify the circuit configuration. The reception signals from the antennas A and B are tuned and amplified by the front ends 33a and 33b to generate an intermediate frequency signal. Each front end 33
a and 33b provided with signal meters 35a and 35b
The reception strength is detected by the comparison means 36 and the comparison and selection means 36 compares the reception strength. By this comparison, the output from the front end having a high reception intensity is switched by the switching means 32 and sent to the one-system IF detection section 34.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a receiver in which a received signal having a high received intensity is selected from received signals from a plurality of antennas so that a received signal having a high intensity is always obtained.

[0002]

[Prior Art]

 A so-called diversity type FM tuner is known as a receiver that has a plurality of antennas and can always receive a signal of a high reception level among the reception signals from these antennas and maintain a good reception state. There is. In this system, as shown in FIG. 3, antennas A and B are provided at two different receiving positions (intervals corresponding to a predetermined wavelength) of a car C, and the antennas A and B are used to broadcast the radio wave from the broadcasting station R. It is possible to receive signals with different electric field strengths, and by selecting one of the receiving paths, it is possible to always receive with high sensitivity.

FIG. 4 and FIG. 5 are block diagrams of a diversity type FM tuner. The FM tuner 1 shown in FIG. 4 tunes and amplifies the signals received by the antennas A and B, the switching means 2 for selecting the receiving path of either the antenna A or B, and the antenna A or B. A front end 3 that mixes frequencies to generate an intermediate frequency (IF) output and an IF detection unit 4 that detects the IF output are provided. In the diversity system, for example, the reception from one antenna A is prioritized, and the intensity of the received signal obtained by the signal meter 5 provided in the IF detection unit 4 is detected by the detection unit (diversity switching unit) 6. However, when the reception intensity from the antenna A is extremely lowered, the switching means 2 switches the reception path to the antenna B.

In the FM tuner 11 shown in FIG. 5, separate receiving systems are provided for the antennas A and B. The front end 13a and the IF detection unit 14a are connected to the reception path of the antenna A, and the front end 13b and the IF detection unit 14b are connected to the reception path of the antenna B. Then, comparison selection means 16 for comparing and selecting the reception intensities from the signal meters 15a and 15b provided in the respective IF detection parts 14a and 14b is provided, and the switching means 12 is operated by the comparison selection operation of the comparison selection means 16. Under control, the reception output from either IF detection unit 14a or 14b is selected.

In this method of selecting the receiving system, the receiving system with the higher level is selected from the received signals of the antenna A system and the antenna B system in which the receiving strength fluctuates as the electric field strength changes as shown in FIG. To be done. In FIG. 6, the level change of the received signal by the receiving system of the antenna A and the receiving system of the antenna B is shown by a broken line, and the receiving signal selected by the switching means 12 is shown by a solid line.

[0006]

[Problems to be solved by the device]

 In the diversity FM tuner 1 shown in FIG. 4, for example, the reception path from one antenna A 1 is prioritized, and when the reception intensity from this reception path decreases, the reception path from the antenna B 1 is switched to. However, it is not always possible to select the optimum reception path.

On the other hand, the FM tuner 11 shown in FIG. 5 compares the intensities of the received signals in the respective IF detectors 14a and 14b to select and switch the receiving path. Therefore, as shown in FIG. It is possible to select a reception path for obtaining the reception level of. However, in the FM tuner shown in FIG. 5, the signal detectors 15a and 15b provided in the IF detectors 14a and 14b are used to detect the reception intensity. As shown in (2), two sets are required, resulting in waste of circuit configuration. That is, conventionally, since the signal intensity provided in the chip of the IF detection unit is used to detect the reception intensity and output it to the comparison and selection means 16, two sets of IF detection units are provided. Therefore, the circuit configuration has an extra set of IF detection units.

The present invention is intended to solve the above-mentioned conventional problems, and to provide a receiver having a diversity function capable of always performing reception of optimum intensity and having an efficient circuit configuration. Has a purpose.

[0009]

[Means for Solving the Problems]

 The receiver according to the present invention compares a plurality of antennas, a front end provided corresponding to the plurality of antennas, a signal meter provided for each of these front ends, and outputs of each signal meter by comparing them. It is characterized in that a comparison and selection means for selecting a front end with high strength and a switching means for sending the reception output from the selected front end to the intermediate frequency processing unit in the subsequent stage are provided.

[0010]

[Action]

 In the above means, the received signals received by the different antennas are tuned, amplified and frequency mixed by the different front ends to generate the IF signal. The signal meters provided for each front end compare the strengths of the received signals from the respective antenna paths, select a system with a high strength, and the selected received signals are sent to the IF processor of one system. It will be sent so that you can always receive with the best reception strength.

[0011]

【Example】

 Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a diversity type FM tuner according to an embodiment of the present invention. FIG. 1 is a circuit block diagram of an FM tuner 31 having a diversity function as an embodiment of a receiver according to the present invention, and FIG. 2 is a circuit block diagram showing an example of a front end circuit configuration. In this embodiment, front ends 33a and 33b are provided respectively at antennas A and B provided at different positions, and signal meters 35a and 35b are built in the front ends 33a and 33b, respectively. For the front ends 33a and 33b, signal meters 35a and 35b built in one chip are used.

FIG. 2 shows an example of a configuration inside the chip of the one front end 33a. The configuration of the other front end 33b is also the same. The front end 33a provides a tuning section 41 for tuning the broadcast wave received by the antenna A or B, an RF stage amplification section 42, an amplified RF signal and a local oscillation frequency from the local oscillation section 44. It has a frequency mixer 43 that mixes to obtain an IF signal, and an AGC circuit (automatic gain control circuit) 45 that sets the amplification factor of the amplification section 42 based on the output from the IF signal. Then, a signal meter 35a or 35b for detecting the intensity of the IF output obtained from the frequency mixer 43 is provided, and these are configured in one chip. The FM tuner of FIG. 1 is provided with front ends 33a and 33b each configured as one chip.

The signal meter 35a and the signal meter 35b are both connected to the comparison / selection means 36. The comparison / selection means 36 compares the received electric field strengths detected by the signal meters 35a and 35b, and the switching means 32 provided at the subsequent stage compares the output from the front end 33a or 33b having a high received electric field strength. It is selected and output to the IF detection unit 34 in the subsequent stage.

Next, the reception operation of the FM tuner 31 having the above configuration will be described. The broadcast waves received by the antennas A and B are tuned and amplified by the respective front ends 33a and 33b to generate intermediate frequency signals. The strengths of the received signals received by the front ends 33a and 33b are detected by the signal meters 35a and 35b. In this signal meter, the frequency-mixed IF signal is rectified by the front-end frequency mixer 43 and converted into a DC voltage, and this voltage is compared with each other by the comparison / selection means 36.

The outputs from the front ends 33 a 1 and 33 b selected by the comparison / selection means 36 as high reception strength are switched and selected by the switching means 32, and are output to the IF detection section 34. The IF detection section 34 detects the received IF output. A signal meter may be incorporated in the IF detection unit 34, and the received signal level in the seek operation (automatic channel selection operation) or the like may be detected by the signal meter.

Further, the front ends 33a and 33b are not limited to one chip, but the front ends 33a and 33b, the signal meters 35a and 35b, the comparison selection means 36, and the switching means may all be configured as a one-chip component P. .. The present invention is not limited to FM receivers, but can be implemented in AM receivers and the like. It is not limited to receivers that receive broadcast waves, but can be used in various receiving devices such as transceivers.

[0017]

[Effect of the device]

 According to the present invention described in detail above, since the reception path is switched according to the reception output of each front end, the IF detection section and the like need only be one system, and the reception intensity from each front end is compared, The receiving path can be switched, and high-sensitivity reception is always possible.

[Brief description of drawings]

FIG. 1 is a diversity system F according to an embodiment of the present invention.
It is a block diagram of an M tuner.

FIG. 2 is a circuit block diagram showing an example of a configuration of a front end.

FIG. 3 is a diagram for explaining the principle of a diversity type FM tuner.

[Fig. 4] Diversity method F for switching only the antenna
It is a block diagram of an M tuner.

FIG. 5 is a block diagram of a diversity FM tuner that switches between two reception systems.

FIG. 6 is a diagram for explaining reception characteristics of a diversity FM tuner.

[Explanation of symbols]

 31 FM tuner 32 switching means 33a, 33b front end 34 IF detection section 35a, 35b signal meter 36 comparison / selection means A, B antenna

Claims (1)

[Scope of utility model registration request] 1. A plurality of antennas, front ends provided corresponding to the plurality of antennas, a signal meter provided for each of these front ends, and the output of each signal meter are compared to obtain a high reception intensity. A receiver comprising comparison and selection means for selecting a front end, and switching means for sending a reception output from the selected front end to an intermediate frequency processing unit in a subsequent stage.