WO2007116931A1

WO2007116931A1 - Receiving device and electronic device using same

Info

Publication number: WO2007116931A1
Application number: PCT/JP2007/057645
Authority: WO
Inventors: Yoshitaka Nagatomi; Yasunobu Tsukio
Original assignee: Panasonic Corporation
Priority date: 2006-04-07
Filing date: 2007-04-05
Publication date: 2007-10-18
Also published as: JP2007281909A

Abstract

A receiving device is provided with a variable band filter having a variable passing frequency band; a control section for setting the passing frequency band of the variable band filter to a plurality of passing frequency bands; and a detecting section for outputting data indicating qualities of signals of the passing frequency bands outputted from the variable band filter, respectively. The control section determines the passing frequency band of the variable band filter based on the data. In the receiving device, a receiving circuit can receive high quality signals.

Description

Specification

Receiving device and electronic device using the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a receiving apparatus and an electronic apparatus such as a portable terminal and a car-mounted television using the receiving apparatus.

Background art

FIG. 4 is a block diagram of a conventional receiving apparatus 1. The receiving device 1 includes a band-variable filter 3 that passes a signal in a desired band among signals received by the antenna 2, a receiver circuit 4 that converts a signal output from the band-variable filter 3 force S into an intermediate frequency, and a receiver circuit 4 And a demodulating circuit 5 for demodulating the signal output from the.

[0003] The receiving device 1 includes a band control unit 6 that controls the pass frequency band of the band-variable filter 3 according to the channel selected by the user. For example, when the first channel is selected, the band control unit 6 determines the pass frequency band of the band variable filter 3 as the first channel and outputs the signal of the first channel to the receiving circuit 4.

[0004] In the receiving apparatus 1, when an interference wave is present in the channel selected by the user and the frequency band in the vicinity thereof, the quality of the signal input to the receiving circuit is degraded.

Disclosure of the invention

[0005] A receiving device includes a variable band filter having a variable pass frequency band, a control unit that sets the pass frequency band of the variable band filter to a plurality of pass frequency bands, and a plurality of passes output by the variable band filter. And a detector that outputs a plurality of data indicating the quality of the signal in the frequency band. The control unit determines the pass frequency band of the band variable filter based on the plurality of data.

In this receiving apparatus, the receiving circuit can receive a signal of good quality.

Brief Description of Drawings

FIG. 1 is a block diagram of an electronic device in an embodiment of the present invention.

FIG. 2 is a circuit diagram of a band-variable filter of the receiving device of the electronic device in the embodiment. FIG. 3A shows a table stored in the receiving apparatus in the embodiment.

FIG. 3B shows a table stored in the receiving apparatus in the embodiment.

FIG. 4 is a circuit diagram of a conventional receiving apparatus.

Explanation of symbols

[0008] 9 Band-variable filter

20 Detector

21 Control unit

22 Memory unit

51 Signal processing circuit

53 batteries

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a block diagram of electronic device 1001 according to the embodiment of the present invention. An electronic device 1001 such as a portable terminal or an on-vehicle TV has a receiving device 7. The receiving device 7 includes a variable band filter 9 connected to the antenna 8, a receiving circuit 10 that converts a signal output from the variable band filter 9 into an intermediate frequency signal, and a demodulation that demodulates the signal output from the receiving circuit 10. Circuit 11. The electronic device 1001 further includes a signal processing circuit 51 that processes a signal output from the demodulation circuit 11 and a display unit 52 that displays a signal output from the signal processing circuit 51.

[0010] The antenna 8 is, for example, an antenna for a very high frequency band, and receives a radio wave of about 770 MHz with a power of about 470 MHz. A UHF band radio wave is composed of frequency bands of a plurality of channels, and the frequency band of each channel is composed of a plurality of frequency bands of, for example, 13 segments.

FIG. 2 is a circuit diagram of the variable band filter 9. The band variable filter 9 has a variable pass frequency band that allows a predetermined segment in the frequency band corresponding to the channel selected by the user to pass. The variable bandwidth filter 9 is connected in parallel with the input variable capacitor 12 connected in series to the antenna 8, the output variable capacitor 13 connected between the input variable capacitor 12 and the receiving circuit 10, and the resonant variable capacitor 14. The fixed inductor 15 is made up of. Input variable capacitor 12 and output variable capacitor 13 are connected at connection point 14A. Resonance variable capacitor 14 is connected Connected between connecting point 14A and ground 14B. The output variable capacitor 13 is connected to the input variable capacitor 12 in series. The input variable capacitor 12, the output variable capacitor 13, and the resonance variable capacitor 14 are, for example, varicap diodes. By changing the voltage Vt supplied to the band variable filter 9, that is, the input variable capacitor 12, the output variable capacitor 13, and the voltage Vt supplied to the resonance variable capacitor 14, the input variable capacitor 12, the output variable capacitor 13, and the resonance variable capacitor 14 capacities change.

As shown in FIG. 1, the receiving circuit 10 is composed of, for example, a high-frequency integrated circuit, and a high-frequency amplifying unit 16 that amplifies a signal output from the band variable filter 9 and a signal output from the high-frequency amplifying unit 16 Is converted to an intermediate frequency signal, a filter 18 that removes noise from the signal output from the mixing unit 17, and an intermediate frequency amplifier 19 that amplifies the signal output from the filter 18. The receiving circuit 10 outputs a signal output from the intermediate frequency amplifier 19.

The demodulator 54 of the demodulator circuit 11 demodulates the intermediate frequency signal output from the intermediate frequency amplifier 19. The signal processing circuit 51 processes the signal demodulated by the demodulator 54 and outputs a video signal and an audio signal. The display unit 52 displays and outputs video signals and audio signals.

The demodulation circuit 11 is composed of, for example, an orthogonal frequency division multiplexing integrated circuit, a detection unit 20 that detects the quality of a signal output from the reception circuit 10, and a band-variable filter based on the quality detected by the detection unit 20 The control unit 21 controls nine passbands, and a storage unit 22 connected to the control unit 21.

[0015] Next, the operation of the receiving device 7 will be described.

FIGS. 3A and 3B show tables stored in the storage unit 22 and show the relationship between the pass frequency band of the band-variable filter 9 and the voltage Vt supplied to the band-variable filter 9. Figure 3A shows the initial state of the table shown in Figure 3B.

[0017] First, when the user selects, for example, a 14-th channel seventh segment program in the UHF band, the control unit 21 sets the voltage Vt supplied to the band variable filter 9 to 0. IV. Thereby, the pass frequency band of the band variable filter 9 is set to the pass frequency band B1 having a center frequency lower than the predetermined frequency band of the seventh segment within the frequency band corresponding to 14 channels. The pass frequency band B1 has a signal attenuation force at the center frequency of the pass frequency band B1, and further has a bandwidth that attenuates, for example, 3 dB. Includes the frequency band of a seventh segment. The variable band filter 9 passes the signal in the pass frequency band B 1 out of the signal sent from the antenna 8. The receiving circuit 10 receives the signal of the pass frequency band B1 output from the band variable filter 9. The detection unit 20 detects a carrier Z noise (C / N) ratio as data indicating the quality of the signal in the pass frequency band B 1. When the detected CZN ratio is 40 dB, the control unit 21 determines that the voltage Vt value 0.IV output to the band-variable filter 9 and 40 dB of the CZN ratio value are the quality of the signal in the pass frequency band B1. Is stored in the storage unit 22 as data indicating.

[0018] Next, the control unit 21 sets the voltage Vt supplied to the band variable filter 9 to 0.11V.

As a result, the pass frequency band of the band variable filter 9 is set to the pass frequency band B2 having a center frequency within the frequency band of the seventh segment within the frequency band corresponding to 14 channels. The pass frequency band B2 has a bandwidth that further attenuates, for example, 3 dB from the signal attenuation amount at the center frequency of the pass frequency band B2. The band variable filter 9 passes the signal in the pass frequency band B2 among the signals transmitted from the antenna 8. The receiving circuit 10 receives the signal of the pass frequency band B2 output from the band variable filter 9. The detection unit 20 detects a CZN ratio indicating the quality of the signal in the pass frequency band B2. When the detected C ZN ratio is 60 dB, the control unit 21 determines that the voltage Vt output to the variable band filter 9 is 0.1V and the CZN ratio value 60 dB is Stored in the storage unit 22 as data indicating quality.

Next, the control unit 21 sets the voltage Vt supplied to the band variable filter 9 to 0.12V. As a result, the pass frequency band of the band-variable filter 9 is set to the pass frequency band B3 having a center frequency higher than the frequency band of the seventh segment within the frequency band corresponding to 14 channels. The pass frequency band B3 has a bandwidth that further attenuates, for example, 3 dB from the signal attenuation at the center frequency of the pass frequency band B3, and includes a frequency band of a seventh segment that is a predetermined frequency band. The variable band filter 9 passes the signal of the pass frequency band B3 among the signals transmitted from the antenna 8. The receiving circuit 10 receives the signal in the pass frequency band B3 output from the band variable filter 9. The detection unit 20 detects a CZN ratio indicating the quality of the signal in the pass frequency band B3. When the CZN ratio is, for example, 50 dB, the control unit 21 determines that the voltage Vt output to the band-variable filter 9 is 0.12 V The N ratio value 50 dB is stored in the storage unit 22 as data indicating the quality of the signal in the pass frequency band B3. In this manner, the control unit 21 stores data indicating the quality of signals in the plurality of pass frequency bands B1 to B3 in the storage unit 22, and stores the table shown in FIG. 3B.

[0020] Based on the table shown in FIG. 3B stored in the storage unit 22, the control unit 21 determines the voltage Vt supplied to the band variable filter 9 to a value 0.1 IV having the largest CZN ratio, The pass frequency band of variable filter 9 is determined as pass frequency band B2.

As described above, the control unit 21 determines the pass frequency band of the band-variable filter 9 in the frequency band having the best quality among the frequency bands of the channel selected by the user. Can receive the signal.

[0022] Instead of the CZN ratio, the detection unit 20 may detect the bit error rate (BER) of the signal output from the band variable filter 9 as data indicating the quality of the signal. The control unit 21 determines the pass frequency band of the band variable filter 9 based on the BER of the signals of the plurality of pass frequency bands B1 to B3 output by the band variable filter 9 detected by the detection unit 20. . As a result, the detection unit 20 can detect the quality of the signal more accurately, and can improve the quality of the signal received by the reception circuit 10. When the data indicating the quality of the signal detected by the detection unit 20 is CZN ratio, the signal quality by the detection unit 20 can be detected in a time shorter than the BER.

[0023] The control unit 21 may determine the pass frequency band of the band variable filter 9 as described above at predetermined time intervals. As a result, the receiving circuit 10 can continuously receive a high-quality signal.

The electronic device 1001 further includes a battery 53 that drives the receiving device 7, the signal processing circuit 51, and the display unit 52. The control unit 21 may detect the remaining amount of the battery 53. When the remaining amount of the battery 53 is greater than a predetermined value, the control unit 21 may determine the pass frequency band of the band variable filter 9 as described above. The control unit 21 does not perform the operation of determining the pass frequency band of the band variable filter 9 when the remaining amount of the battery 53 is equal to or less than the predetermined value. Thereby, it is possible to prevent the control unit 21 from consuming the battery 53.

[0025] The control unit 21 reduces the data indicating the quality of the signal detected by the detection unit 20 to a predetermined level or less. In other words, the pass frequency band of the band-variable filter 9 may be determined when the quality is lower than that of the predetermined bell. When the data indicating the quality of the signal detected by the detection unit 20 is better than a predetermined level, the reception circuit 10 can continuously receive a signal of good quality while suppressing power consumption.

The control unit 21 may be V provided in the signal processing circuit 51 connected to the output side of the demodulation circuit 11. Since the processing speed of the signal processing circuit 51 is generally higher than the processing speed of the demodulation circuit 11, it is possible to shorten the time for the control unit 21 to determine the pass frequency band of the band-variable filter 9.

Industrial applicability

[0027] In this receiving apparatus, the receiving circuit can receive signals of good quality and is useful for electronic devices such as portable terminals and automobile-mounted televisions.

Claims

The scope of the claims

[1] a band-variable filter having a variable pass frequency band;

A control unit for setting the pass frequency band of the band variable filter to a plurality of pass frequency bands;

A detection unit for outputting a plurality of data respectively indicating the quality of the signals in the plurality of pass frequency bands output by the band variable filter;

And the control unit determines the pass frequency band of the variable band filter based on the plurality of data.

[2] The receiving device according to claim 1, wherein a center frequency of each of the plurality of pass frequency bands is variable in units of segments within a predetermined frequency band.

[3] The receiving device according to claim 1, wherein the plurality of pass frequency bands include a predetermined frequency band.

4. The receiving device according to claim 1, further comprising a storage unit that stores the plurality of data.

5. The receiving device according to claim 1, wherein the plurality of data are carrier Z noise ratios of the signal.

6. The receiving device according to claim 1, wherein the plurality of data are bit error rates of the signal.

[7] The control unit sets the pass frequency band of the band variable filter to the plurality of pass frequency bands at predetermined time intervals,

The detection unit outputs a plurality of data indicating the quality of the signals of the plurality of pass frequency bands output by the band variable filter at each predetermined time interval, and the control unit outputs the data at each predetermined time interval. The receiving device according to claim 1, wherein the pass frequency band of the band-variable filter is determined based on the plurality of data.

[8] The battery further includes a battery that drives the control unit, the band variable filter, and the detection unit, and the control unit includes the pass frequency of the band variable filter when the remaining amount of the battery is greater than a predetermined value. Set a band to the plurality of pass frequency bands,

A plurality of detection units each indicating a quality of a signal in the plurality of pass frequency bands output by the band variable filter when the remaining amount of the battery is greater than the predetermined value; Output the data of

The receiving device according to claim 1, wherein the control unit determines the pass frequency band of the band-variable filter based on the plurality of data when the remaining amount of the battery is greater than the predetermined value. .

[9] The control unit sets the pass frequency band of the band variable filter to the plurality of pass frequency bands when the data output from the detection unit is equal to or lower than a predetermined level. When the data output by the detection unit is equal to or lower than the predetermined level, a plurality of data respectively indicating the quality of the signals of the plurality of pass frequency bands output by the band variable filter are output;

2. The control unit according to claim 1, wherein the control unit determines the pass frequency band of the band-variable filter based on the plurality of data when the data output from the detection unit is equal to or lower than the predetermined level. Receiver.

[10] A variable-band filter having a variable pass frequency band;

A signal processing circuit for processing a signal output from the band-variable filter;

And the control unit determines the pass frequency band of the band-variable filter based on the plurality of data.

11. The electronic device according to claim 10, wherein the control unit is provided in the signal processing circuit.