JP4735122B2 - Receiving module and receiving device using the same - Google Patents

Description

  The present invention relates to a receiving module for receiving a signal and a receiving device using the receiving module.

  Hereinafter, a conventional receiving module will be described with reference to FIG. In FIG. 3, the receiving module 103 is a demodulator including a first receiving unit 106 and a second receiving unit 107 that receive diversity, and a demodulation LSI connected to the output side of the first receiving unit 106 and the second receiving unit 107. Part 108. The demodulator 108 includes a first detector 122 that detects the level of the signal from the first receiver 106 and a second detector 129 that detects the level of the signal from the second receiver 107. Further, the first receiving unit 106 includes a first amplifying unit 112 that amplifies the received signal based on an AGC (Automatic Gain Control) voltage generated based on the level detected by the first detecting unit 122. The second receiving unit 107 includes a second amplifying unit 116 that amplifies the received signal based on the AGC voltage generated based on the level detected by the second detecting unit 129.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2004-274603 A

  The conventional reception module 103 is changed from a single reception (non-diversity reception) state where a signal is received only by the first reception unit 106 to a diversity reception state where the first reception unit 106 and the second reception unit 107 receive signals. When switching, when the difference between the initial value of the AGC voltage and the convergence value is large, the AGC voltage supplied to the second amplification unit 116 is finally converged to a constant value after the second receiving unit 107 operates. For example, it took a long time of 100 milliseconds.

  Therefore, the present invention solves such a problem, and shortens the time from when the second receiving unit operates until the AGC voltage supplied to the second amplifying unit finally converges to a constant value. For the purpose.

To achieve this object, the demodulator in the receiving module of the present invention adjusts the amplification level of the signal based on the signal level detected by the first detector to the second amplifier when switching from single reception to diversity reception. Supply as a signal.

  As a result, when the second receiving unit operates, the AGC voltage supplied to the second amplifying unit becomes a value close to a constant value that is finally stabilized. Therefore, the AGC voltage supplied to the second amplifying unit is stabilized from a value close to the constant value toward the constant value. As a result, it is possible to shorten the time from when the second receiving unit operates until the AGC voltage supplied to the second amplifying unit finally converges to a constant value.

(Embodiment 1)
Hereinafter, Embodiment 1 in the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a receiving device according to Embodiment 1 of the present invention.

  The receiving device includes a first antenna 1, a second antenna 2, a receiving module 3 connected to the output side of the first antenna 1 and the second antenna 2, and a signal connected to the output side of the receiving module 3. It has a processing unit 4 and a display unit 5 connected to the output side of the signal processing unit 4.

  The reception module 3 is connected to the first antenna 1 and the second antenna 2, respectively, and receives the diversity reception, and the first reception unit 6 and the second reception unit 7, and the demodulation connected to the output side of the first and second reception units. Part 8.

  The first receiver 6 receives, for example, an external terrestrial digital broadcast signal received by the first antenna 1. The first receiving unit 6 includes a first input filter (not shown) on the output side of the first antenna 1 and a first high-frequency amplifier 9 that amplifies a signal from the first input filter. Further, the first receiving unit 6 mixes the signal from the first local oscillation unit 10 for transmitting the local oscillation signal and the signal from the first high frequency amplification unit 9 with the local oscillation signal, and outputs the signal from the first high frequency amplification unit 9. And a first mixing unit 11 that converts the frequency. Further, the first receiving unit 6 includes a first band limiting filter (not shown) that suppresses signals of unnecessary frequencies other than the desired signal among the signals from the first mixing unit 11, and the first band limiting filter. A first amplifying unit 12 for amplifying a signal from The first amplifying unit 12 determines the amplification degree of the signal from the first band limiting filter based on the AGC voltage supplied from the demodulating unit 8.

  The second receiving unit 7 receives an external signal received by the second antenna 2 in the same manner as described above. Similarly to the above, the second receiver 7 includes a second input filter (not shown), a second high-frequency amplifier 13, a second local oscillator 14, a second mixer 15, and a second band. A limiting filter (not shown) and a second amplifying unit 16 are included. Similarly to the above, the second amplifying unit 7 also determines the amplification degree of the signal from the second band limiting filter based on the AGC voltage supplied from the demodulating unit 7.

  The first receiving unit 6 and the second receiving unit 7 are controlled by the diversity control unit 17 as to whether single reception is performed on one side or diversity reception is performed on both sides.

  The demodulator 8 includes a first AD converter 18 that converts an analog signal from the first receiver 6 into a digital signal. The demodulator 8 also includes a first multiplier 19 that converts the signal from the first AD converter 18 into a complex signal obtained by orthogonal demodulation and frequency-converts the signal to a baseband signal from which the carrier wave component is removed. Further, the demodulator 8 includes a first Fourier transform unit 20 that converts a time-domain data string of the baseband OFDM signal supplied from the first multiplier 19 into a frequency-domain data string. In addition, the demodulator 8 includes a first demodulation processor 21 that demodulates the signal from the first Fourier transform unit 20.

  The demodulator 8 includes a first detector 22 that detects the level of the signal from the first AD converter 18. The signal level refers to the signal strength. Then, the demodulator 8 includes a first loop filter 23 that smoothes signal level fluctuations in the signal from the first detector 22, and a first loop filter 23 that converts the signal from the first loop filter 23 into an AGC voltage value. 1 conversion unit 24 is provided. The demodulator 8 converts the digital AGC voltage value from the first converter 24 into an analog AGC voltage, and supplies the AGC voltage to the first amplifier 12 of the first receiver as an amplification adjustment signal. A first DA converter 25.

  Similarly to the above, the demodulator 8 includes a second AD converter 26, a second multiplier 27, a second Fourier transformer 28, and a second demodulator 29 in this order. Similarly to the above, the demodulator 8 includes the second detector 30, the second loop filter 31, the second converter 32, and the second DA converter 33 on the output side of the second AD converter 26. In this order.

  The first detection unit 22, the first loop filter 23, the first conversion unit 24, and the first DA conversion unit 25 constitute a first AGC processing unit 34. The second detection unit 30, the second loop filter 31, the second conversion unit 32, and the second DA conversion unit 33 constitute a second AGC processing unit 35.

  Further, the demodulating unit 8 includes a diversity combining unit 36 that combines the signal from the first demodulation processing unit 21 and the signal from the second demodulation processing unit 29 in the diversity reception state. Further, the demodulating unit 8 includes a diver control unit 17 that controls the diver combining unit 36, the first receiving unit 6, and the second receiving unit 7, and switches between a single receiving state and a diversity receiving state. In addition, the demodulating unit 8 is configured to output the B.D. E. R. The diver control unit 17 has a BER measurement unit 37 that determines the magnitude of (Bit Error Rate), and the diver control unit 17 sets the reception module 3 to a single reception state in accordance with the magnitude of the BER supplied from the BER measurement unit 37. Or whether to enter the diversity reception state.

  Further, the demodulator 8 has a switch unit 38 that supplies the AGC voltage value from the first converter 24 to the second DA converter 33 as an amplification degree adjustment signal based on the signal from the diver controller 17.

  Next, the operation of the receiving module 3 will be described.

  As an initial state, a case is assumed where the receiving module 3 is in a single receiving state in which only the first receiving unit 6 receives an external signal. When the BER of the signal from the first receiving unit 6 measured by the BER measuring unit 37 is larger than a predetermined value in the single receiving state with only the first receiving unit 6, the diver control unit 17 receives the signal. The module 3 is switched from the single reception state to the diversity reception state.

  At this time, the diver control unit 17 operates not only the first receiving unit 6 but also the second receiving unit 7, and causes the diver combining unit 36 to send the signal from the first demodulation processing unit 21 and the second demodulation processing unit 29. Combine the signals. At this time, the diver control unit 34 causes the switch unit 38 to supply the AGC voltage value from the first conversion unit 24 to the second DA conversion unit 33 as an amplification degree adjustment signal.

  When the receiving module 3 is provided in a small receiving device such as a portable terminal, the first antenna 1 and the second antenna 2 are arranged at positions close to each other, so that the AGC voltage supplied to the first receiving unit 6 The AGC voltage supplied to the second receiving unit 7 is generally approximate. Therefore, with the above configuration, when the second receiving unit 7 operates, the AGC voltage supplied to the second amplifying unit 16 has a magnitude close to a constant value that is finally stabilized. Therefore, the AGC voltage supplied to the second amplifying unit 16 is stabilized from a value close to the constant value toward the constant value. As a result, it is possible to shorten the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value. The time when the receiving unit 7 operates may be when power is supplied to the receiving unit 7 or when the local oscillation signal from the local oscillating unit 14 is set to a predetermined frequency. Further, by providing the switch unit 38 in the demodulator 8 which is a demodulation LSI, the receiving module 3 can be made smaller than providing an analog switch outside the demodulator 8.

(Embodiment 2)
Hereinafter, a receiving module and a receiving device using the same according to the present embodiment will be described with reference to FIG. Note that, unless otherwise specified, the same as in the first embodiment.

  The difference between the second embodiment and the first embodiment is that a switch unit 39 is provided between the first loop filter 23 and the second loop filter 31 as shown in FIG.

  The diversity control unit 17 amplifies the signal level detected by the first detection unit from the first loop filter 23 to the second loop filter 31 when switching the reception module 3 from the single reception state to the diversity reception state. It is supplied as a degree adjustment signal.

  When the characteristics of the first receiver 6 and the characteristics of the second receiver 7 are different, the conversion characteristics of the first converter 24 and the conversion characteristics of the second converter 32 may be different. Therefore, the signal level detected by the first detection unit before being converted by the first conversion unit 24 is used as it is, rather than the AGC voltage value converted by the first conversion unit 24 being supplied to the second AGC processing unit 35. When the voltage is supplied to the second AGC processing unit 35, the AGC voltage supplied to the second amplifying unit 16 becomes closer to a constant value that is finally stabilized. Accordingly, it is possible to further shorten the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value.

  In addition, when the signal level detected by the first detection unit 22 is supplied from the first AGC processing unit 34 to the second AGC processing unit 35 for only a short time, the AGC voltage supplied to the second amplification unit 16 is second detected. There is a possibility of being affected by an unstable signal from the unit 30. Therefore, it is desirable that the switch unit 39 supplies the signal level detected by the first detection unit 22 to the second AGC processing unit 35 for a predetermined time from when the second reception unit 7 operates. Thereby, the possibility that the AGC voltage supplied to the second amplifying unit 16 is affected by an unstable signal from the second detecting unit 30 can be reduced. As a result, the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value can be more reliably reduced.

  Further, the switch unit 39 may supply the signal level detected by the first detection unit 22 to the second AGC processing unit 35 before the second reception unit 7 switches from non-operation to operation. Thereby, during the operation of the second receiving unit 7, since the signal level already detected by the first detecting unit 22 is supplied to the second AGC processing unit 35, the signal level detected by the first detecting unit 22 is The time loss when the switch unit 39 supplies the second AGC processing unit 35 can be reduced. As a result, it is possible to further reduce the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value.

  In addition, when the receiving module 3 is provided in a small receiving device such as a portable terminal, the first antenna 1 and the second antenna 2 are arranged at positions close to each other, so that the signal detected by the first detecting unit 22 The fluctuation in level and the fluctuation in signal level detected by the second detection unit 30 are approximate. Therefore, it is desirable that the switch unit 39 supplies the fluctuating signal level to the second AGC processing unit 35 in accordance with the fluctuation of the signal level detected by the first detection unit 22 for a predetermined time. Thereby, it is possible to further shorten the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value.

  The switch unit 39 may supply a signal level obtained by adding a certain offset amount to the signal level detected by the first detection unit 22 to the second AGC processing unit 35 as an amplification degree adjustment signal. If the signal level detected by the first detection unit 22 is supplied to the second AGC processing unit 35 as it is, the amplification amount of the second amplification unit 16 may be insufficient with respect to the signal level received by the second antenna 2. As a result, in that case, the amplitude level supplied to the second AD converter becomes small, leading to deterioration of reception characteristics. Therefore, the probability that the signal output from the second amplifying unit 16 deteriorates by supplying a signal level obtained by adding a negative offset amount to the level of the signal detected by the first detecting unit 22 to the second amplifying unit 16. Can be lowered.

  In addition, since the optimum value of the offset amount varies depending on reception environments such as multipath and mobile reception, adaptive control can be performed by making it possible to set from the outside.

  Furthermore, the demodulating unit 8 calculates a correlation coefficient between the level of the signal detected by the first detection unit 22 and the level of the signal detected by the second detection unit 30 (not shown). ). The correlation coefficient is a value representing the strength of the relationship between the two level fluctuations. When one fluctuation is completely unrelated to the other fluctuation, the correlation coefficient is 0. The stronger the relationship is, the absolute value of the correlation coefficient is 1. Get closer to. Therefore, when the absolute value of the correlation coefficient calculated by the level correlation coefficient calculation unit is equal to or greater than a certain threshold value, it can be determined that the two level fluctuations are correlated and the optimum value of the AGC voltage is close. In this case, the switch unit 39 supplies the level detected by the first detection unit 22 to the second AGC processing unit 35. Thereby, it is possible to more reliably reduce the time from when the second receiving unit 7 operates until the AGC voltage supplied to the second amplifying unit 16 finally converges to a constant value.

  Also, when the directivity of the two antennas is different, the correlation coefficient differs depending on the reception environment, so adaptive control is realized by allowing the correlation coefficient threshold to be set externally. can do.

  The reception module of the present invention can smoothly switch from the single reception state to the diversity reception state in a short time, and can be used for a portable terminal or the like.

Block diagram of receiving apparatus in Embodiment 1 of the present invention Block diagram of receiving apparatus in Embodiment 2 of the present invention Block diagram of a receiving device in a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st antenna 2 2nd antenna 3 Reception module 4 Signal processing part 5 Display part 6 1st reception part 7 2nd reception part 8 Demodulation part

Claims (11)

A first receiver and a second receiver for diversity reception, and a demodulator connected to the output side of the first and second receivers,
A reception module having a switching function between single reception for receiving a signal only by the first reception unit and diversity reception for receiving a signal by the first reception unit and the second reception unit,
The demodulator has a first detector that detects the level of the signal from the first receiver, and a second detector that detects the level of the signal from the second receiver,
The first reception unit includes a first amplification unit that amplifies the received signal based on the signal from the first detection unit,
The second receiving unit includes a second amplifying unit that amplifies the received signal based on the signal from the second detecting unit,
When switching from single reception to diversity reception, the demodulation unit supplies a signal based on the level detected by the first detection unit to the second amplification unit as an amplification adjustment signal. The demodulator includes a first converter that converts a signal from the first detector, and a second converter that converts a signal from the second detector, and is converted by the first converter. The receiving module according to claim 1, wherein a signal based on the level detected by the first detection unit before being supplied is supplied to the second conversion unit. The receiving module according to claim 1, wherein the demodulation unit supplies a signal based on the level detected by the first detection unit to the second amplification unit for a predetermined time. The receiving module according to claim 3, wherein the predetermined time is a time from when the second receiving unit operates. The receiving module according to claim 3, wherein the predetermined time is a time before the second receiving unit switches from non-operation to operation. The demodulator supplies the signal based on the level to the second amplifier in accordance with the fluctuation of the level detected by the first detector for the predetermined time. The receiving module described in 1. The reception module according to claim 1, wherein the signal based on the level is a signal obtained by adding a certain offset amount to the level detected by the first detection unit. The receiving module according to claim 7, wherein the offset amount can be set from the outside. A level correlation coefficient calculation unit that calculates a correlation coefficient between the level of the signal detected by the first detection unit and the level of the signal detected by the second detection unit;
When the correlation coefficient calculated by the level correlation coefficient calculation unit at the time of diversity reception is equal to or greater than a certain threshold, when switching from single reception to diversity reception, the demodulation unit is detected by the first detection unit. The receiving module according to claim 1, wherein a signal based on the level is supplied to the second amplifying unit as an amplification adjustment signal. The receiving module according to claim 9, wherein the correlation coefficient threshold value can be set from the outside. A first antenna, a second antenna, a first receiver and a second receiver connected to the first antenna and the second antenna, respectively, for diversity reception, and connected to the output sides of the first and second receivers A demodulation unit, a signal processing unit connected to the output side of the demodulation unit, and a display unit connected to the output side of the signal processing unit,
A receiving device having a switching function between single reception for receiving a signal only by the first receiving unit and diversity reception for receiving a signal by the first receiving unit and the second receiving unit,
The demodulator includes a first detector that detects the level of the signal from the first receiver, and a second detector that detects the level of the signal from the second receiver,
The first reception unit includes a first amplification unit that amplifies the received signal based on the signal from the first detection unit,
The second receiving unit includes a second amplifying unit that amplifies the received signal based on the signal from the second detecting unit,
When switching from single reception to diversity reception, the demodulation unit supplies a signal based on the level detected by the first detection unit to the second amplification unit as an amplification adjustment signal.

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