JP2008061205A - Radio frequency control circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio frequency control circuit which appropriately controls a high frequency processing unit and a modulation-demodulation processing unit, and can avoid communication impossibility when a communication-impossible frequency exists. <P>SOLUTION: In a radio frequency control circuit, with respect to a frequency to be used that is specified by a main control unit 111, when IF or RF specified from received frequency information can not be used when referring to a frequency information storage unit 201, a signal processing control unit 102 reads contents to be changed from the frequency information, changes a set value of a NCO 106 via a setting change circuit 105 according to the contents or performs a frequency change of a local oscillator 109 via an RF control unit 110 to avoid communication impossibility. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio frequency control circuit, and in particular, a radio that performs processing related to transmission and reception using an NCO for generating an IF signal and a local oscillator for generating an RF signal under the control of a main control unit. The present invention relates to a frequency control circuit.

  FIG. 5 is a block diagram showing an outline of a conventional example of the transmission circuit unit of the radio frequency control circuit. The transmission circuit unit 60 of the radio frequency control circuit in FIG. 5 includes a modulation processing unit 600 and a high frequency processing unit 601. A baseband signal (BB signal) as transmission source data is input to the signal processing unit 602 and subjected to predetermined signal processing. The signal processing is signal processing based on the desired framing and encapsulation settings of the BB signal, the setting of the modulation method (AM modulation, FM modulation, 16QAM), and the setting of the multiplexing method (time division, etc.). The signal processing unit 602 is connected to the control bus 620 so that control information such as monitoring information and status display can be transmitted to and received from the main control unit 611 connected to the control bus 620. Has been.

  The modulated signal output from the signal processing unit 602 is delivered to the rate conversion circuit 603, and the sampling rate is increased to a desired rate. A filtering process is usually added to remove unnecessary images generated during rate conversion. Data output from the rate conversion circuit 603 is tuned to a digital intermediate frequency (IF) by an NCO 606 (Numerical Controlled Oscillator) and a mixer 604. The NCO 606 stores setting values in a setting ROM 605 prepared in an external memory or the like. In this case, since the setting values are rarely changed during operation, the setting values are usually changed dynamically. Such a circuit is not incorporated.

  The output signal from the mixer 604 is delivered to the D / A converter 607, converted into an analog signal, and delivered to the high frequency processing unit 601 as an IF signal. In the high frequency processing unit 601, the IF signal delivered from the D / A converter 607 is delivered to the mixer 608 together with the output of the local oscillator 609, and is converted into a desired RF signal. In this way, the BB signal is converted into a radio frequency signal and transmitted as a modulated wave.

  In a normal case, the radio frequency is switched by fixing the IF and switching the frequency of the local oscillator 609 according to the setting from the RF control unit 610 in the high-frequency processing unit 601 at the next stage. The RF control unit 610 is connected to the main control unit 611 via the control bus 620, and transmits / receives frequency setting information and monitoring / control information for setting the frequency of the local oscillator 609. In this case, the switching frequency interval of the local oscillator 609 is generally about several Hz to several kHz even if a PLL circuit or the like is configured, and fine adjustment at a frequency interval smaller than that is a device performance or circuit configuration. It has become difficult. JP-A-2004-104379 discloses a material disclosing a similar technique.

  As described above, since the radio frequency control circuit in the software defined radio system is desired to be compatible with all radio systems, the performance is required to be compatible with a wide frequency band. However, this type of radio frequency control circuit may not be able to communicate at several frequencies due to the influence of the transmitter circuit (for example, wraparound) and the environment in which it is used (for example, the influence of external or surrounding radio waves). There is.

  The present invention has been made in order to solve the above-described problem, and enables the high-frequency processing unit and the modulation / demodulation processing unit to be appropriately controlled, and there is a frequency at which communication is impossible due to various conditions as described above. In this case, an object is to provide a radio frequency control circuit capable of avoiding the communication failure.

  In order to solve the above-described problem, a radio frequency control circuit according to the present invention uses an NCO for generating an IF signal under the control of a main control unit, and a local oscillator for generating an RF signal. In the radio frequency control circuit that performs processing related to transmission and reception, when the radio frequency to be processed is a specific radio frequency, a frequency information storage unit that stores IF and RF to be changed and used as frequency information, A setting change circuit that can change the setting value of the NCO of the modulation / demodulation processing unit for IF setting according to the change instruction, an RF control unit that can change the frequency of the local oscillator according to the change instruction, and a main control unit If the radio frequency to be processed instructed by is a specific radio frequency, I based on the frequency information stored in the frequency information storage unit And a signal processing control section that gives an instruction to change the setting changing circuit and RF control unit to use the RF.

  Since the present invention is configured as described above, the signal processing control unit is instructed from the received frequency information when inquiring to the frequency information storage unit regarding the frequency to be used instructed from the main control unit. When IF or RF cannot be used, the contents to be changed are read from the frequency information, and the setting value of the NCO is changed via the setting change circuit according to the contents, or the frequency of the local oscillator is set via the RF controller. Make changes.

  As described above in detail, according to the present invention, the signal processing control unit is instructed from the received frequency information when inquiring to the frequency information storage unit regarding the frequency to be used instructed from the main control unit. When IF or RF cannot be used, the contents to be changed are read from the frequency information, and the setting value of the NCO is changed via the setting change circuit according to the contents, or the frequency of the local oscillator is set via the RF controller. Make changes. As a result, even if there is an IF or RF that cannot be used for various reasons, the content to be changed in that case is stored in the frequency information storage unit, so the signal processing control unit uses this frequency information. Wireless communication can be executed by changing IF or RF.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing an embodiment of a transmission circuit unit of a radio frequency control circuit according to the present invention, FIG. 2 is a block diagram showing in detail a modulation processing unit of FIG. 1, and FIG. 3 is a block diagram showing FIGS. FIG. 4 is a block diagram showing an embodiment of the receiving circuit section of the radio frequency control circuit according to the present invention.

  The transmission circuit unit 10 in FIG. 1 includes a modulation processing unit 100 and a high frequency processing unit 101. A baseband signal (BB signal) as transmission source data is delivered to the signal processing unit 102 and subjected to predetermined signal processing. The signal processing is signal processing based on a desired framing or encapsulation setting of the BB signal, a setting of a modulation method (AM modulation, FM modulation, 16QAM), a setting of a multiplexing method (such as time division). Further, the signal processing unit 102 is connected to the control bus 120 so that control information such as monitoring information and status display can be transmitted to and received from the main control unit 111 similarly connected to the control bus 120. Has been.

  The modulated signal output from the signal processing unit 102 is delivered to the rate conversion circuit 103, and the sampling rate is increased to a desired rate. A filtering process is usually added to remove unnecessary images generated during rate conversion. Data output from the rate conversion circuit 103 is tuned to a digital intermediate frequency (digital IF) by an NCO 106 (Numerical Controlled Oscillator) and a mixer 104.

  The setting change circuit 105 changes the setting value of the NCO 106 under the instruction of the signal processing unit 102. An output signal from the mixer 104 is delivered to the D / A converter 107, converted into an analog signal, and delivered to the high frequency processing unit 101 as an IF signal. In the high frequency processing unit 101, the IF signal delivered from the D / A converter 107 is converted into an RF signal having a desired frequency by the local oscillator 109 and the mixer 108. In this way, the BB signal is converted into a radio frequency signal and transmitted as a modulated wave.

  In the circuit of FIG. 1, in order to switch the frequency of the radio frequency signal, normally, the IF is fixed and the frequency of the local oscillator 109 is set by the setting from the RF control unit 110 in the subsequent high-frequency processing unit 101 as in the conventional case. Switch the radio frequency. The RF control unit 110 is connected to the main control unit 111 via the control bus 120, and the frequency setting information and the monitoring / control information for setting the frequency of the local oscillator 109 with the main control unit 111. Send and receive.

  However, for communication related to frequencies for which communication is disabled, appropriate setting values are given to the RF control unit 110 and the signal processing unit 102 based on the frequency information. These will be described with reference to FIG. 2 and FIG. 2 shows in more detail the main control unit 111, the setting change circuit 105, and the signal processing unit 102 of the transmission circuit shown in FIG. 1. In the flowchart of FIG. 3, the frequency setting procedure in the circuit of FIG. Will be explained.

  The BB signal that is the data of the transmission source is delivered to the modulation unit 200 (FIG. 2) of the signal processing unit 102, and modulation processing is performed. The modulation unit 200 receives control of the signal processing unit 202, exchanges control signals / monitoring control signals and the like with the signal processing control unit 202, and executes modulation processing. The signal processing control unit 202 is connected to the control bus 120 and is also connected to the main control unit 111 via the control bus 120. The signal processing control unit 202 receives a control signal / monitoring control signal from the monitoring control unit 204 of the main control unit 111 via the control bus 120. For example, transmission start and stop. The data output from the modulation unit 200 is processed by the rate conversion circuit 103, the mixer 104, and the D / A converter 107, and delivered to the high frequency processing unit 101 as an IF signal.

  Here, frequency setting will be described with reference to FIG. When setting the frequency, the frequency control unit 203 of the main control unit 111 transmits frequency information for instructing the setting to the signal processing control unit 202 in the signal processing unit 102 via the control bus 120. (FIG. 3: Step S10). The signal processing control unit 202 receives the frequency information from the frequency control unit 203 and refers to the frequency information in the frequency information storage unit 201 for the frequency information.

  Regarding the IF, the setting value of the NCO 106 corresponding to the frequency information from the frequency control unit 203 is determined (S12). The determined setting value of the NCO 106 is checked against the frequency information stored in the frequency information storage unit 201 to determine whether or not the setting value of the NCO 106 needs to be changed (S13). As a result of the determination in step S13, if the frequency is usable, the signal processing control unit 202 instructs the setting control unit 205 of the setting change circuit 105 to set the NCO 106 with the setting value determined in step S12. finish. In accordance with this instruction, the NCO setting information output unit 206 of the setting change circuit 105 sets a setting value in the NCO 106.

  However, if the frequency is unusable as a result of the determination in step S13, the signal processing control unit 202 sets the setting control unit of the setting change circuit 105 so as to perform the change according to the frequency information in the frequency information storage unit 201. A change instruction is given to 205 (S14). The change instruction is a setting value for change and an instruction to change using the set value. The setting control unit 105 that has received the setting value for changing and the change instruction for setting it sets the setting value to the NCO 106 via the NCO setting information output unit 206, and the NCO 106 that has received the setting value receives the mixer. In cooperation with 104, an IF signal is generated (S15).

  On the other hand, regarding the RF for the inquiry of the frequency information in step S11, the set value of the local oscillator 109 of the high frequency processing unit 101 is determined based on the frequency information (S22). The determined setting value of the local oscillator 109 is checked against the frequency information in the frequency information storage unit 201, and it is determined whether or not the setting value of the local oscillator 109 needs to be changed because it is not usable (S23). If the frequency is usable as a result of the determination in step S23, the signal processing control unit 202 sets the local oscillator 109 with the setting value determined in step S22 via the control bus 120 to the RF control unit 110. Instructed (S24) and the process ends.

  However, if the result of determination in step 23 is that the frequency of the RF is unusable, the signal processing control unit 202 should change the set value and change so as to make the change according to the frequency information in the frequency information storage unit 201. An instruction to that effect is given to the RF control unit 110 of the high-frequency processing unit 101 via the control bus 120. The RF control unit 110 sets the given setting value in the local oscillator 109, and the local oscillator 109 that has received the setting value cooperates with the mixer 108 to generate an RF signal (S25).

  Accordingly, the frequencies of the IF signal and the RF signal can be adjusted simultaneously and collectively. Needless to say, it may be possible to cope with a change in the frequency of either the IF signal or the RF signal. In particular, when an element with high resolution is used for the NCO for generating the IF signal, fine adjustment is possible. The frequency information stored in the frequency information storage unit 201 may be stored in a memory device such as a ROM, or may be stored so as to be rewritable from the outside under the control of the main control unit 111. Good. That is, the frequency information is a set value for setting a frequency in consideration of the surrounding environment, although it depends on the clock configuration of the device, and is not necessarily unique to the device.

  In the above case, if the AD6623, which is a data converter IC manufactured by Analog Devices, is used as the NCO 106 of the modulation processing unit 100, the frequency is set over a wide range with a resolution of about 0.01 Hz, depending on the frequency used. It is possible to avoid the problem by adjusting the IF frequency even when the local oscillation of the local oscillator or the like in the high-frequency processing unit 101 occurs.

  Next, an embodiment of the receiving circuit section of the radio frequency control circuit of the present invention will be described with reference to FIG. The receiving circuit unit 50 in FIG. 4 includes a demodulation processing unit 500 and a high frequency processing unit 501. An RF signal that is received data is input to the high frequency processing unit 501, converted into a desired IF signal by the mixer 508, and delivered to the demodulation processing unit 500. The IF signal delivered to the demodulation processing unit 500 is converted into a digital signal by the A / D converter 507 of the demodulation processing unit 500, and becomes a tuning signal by the NCO 506 and the mixer 504. The setting value of the NCO 506 is controlled by the setting change circuit 505 under the instruction of the signal processing unit 502.

  The output from the mixer 504 is down-converted by the rate conversion circuit 503 so that the sampling frequency is BB processing frequency. A filtering process is usually added to remove unnecessary images generated during rate conversion. The data whose sampling rate has been converted to a desired rate is delivered to the signal processing unit 502, where demodulation processing (AM demodulation, FM demodulation, 16QAM, etc.) is performed to obtain a BB signal and an audio signal. At the time of SSB voice communication, etc., there is a problem that it is difficult to hear the received voice due to a minute frequency shift, and the conventional radio apparatus is also set to a frequency that is easy to hear by performing tuning. Even in such a case, if the present invention is applied, the SSB reception frequency can be finely adjusted.

It is a block diagram which shows embodiment of the transmission circuit part of the radio frequency control circuit of this invention. It is a block diagram which shows the modulation process part of FIG. 1 in detail. 3 is a flowchart for explaining a frequency setting procedure in the circuit shown in FIGS. 1 and 2. It is a block diagram which shows embodiment of the receiving circuit part of the radio frequency control circuit of this invention. It is a block diagram which shows the prior art example of the transmission circuit part of a radio frequency control circuit.

Explanation of symbols

10 transmission circuit unit, 50 reception circuit unit, 100 modulation processing unit, 101, 501 high frequency processing unit, 102, 502 signal processing unit, 103, 503 rate conversion circuit, 104, 108, 504, 508 mixer, 105, 505 setting change Circuit, 106, 506 NCO (Numerically Controlled Oscillator), 107 D / A Converter, 109, 509 Local Oscillator, 110, 510 RF Control Unit, 111 Main Control Unit, 120, 520 Control Bus, 200 Modulation Unit, 201 Frequency Information Storage unit, 202 signal processing control unit, 203 frequency control unit, 204 monitoring control unit, 205 setting control unit, 206 NCO setting information output unit, 500 demodulation processing unit, 507 A / D converter, S10 to S25 steps.

Claims (1)

In a radio frequency control circuit that performs processing related to transmission and reception using an NCO for generating an IF signal under the control of the main control unit and a local oscillator for generating an RF signal,
When the radio frequency to be processed is a specific radio frequency, a frequency information storage unit that stores IF and RF to be changed and used as frequency information;
A setting change circuit capable of changing the setting value of the NCO of the modulation / demodulation processing unit for IF setting in accordance with the change instruction;
An RF control unit capable of changing the frequency of the local oscillator according to the change instruction;
When the radio frequency to be processed instructed from the main control unit is a specific radio frequency, the setting change circuit and the RF are used so as to use IF and RF based on the frequency information stored in the frequency information storage unit. A radio frequency control circuit comprising a signal processing control unit for giving a change instruction to the control unit.

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