JP3397462B2 - Analog-digital conversion circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog-digital conversion circuit provided for supplying a received intermediate frequency signal to a digital signal processing circuit in a wireless communication device such as a digital portable telephone device or a digital cordless telephone device. .

[0002]

2. Description of the Related Art In a digital wireless communication device such as a digital portable telephone device or a digital cordless telephone device, a digital signal processing circuit (not shown) performs signal demodulation processing such as digital demodulation of a received signal, error correction decoding, voice decoding and echo cancellation processing. DSP). In order to perform the above-mentioned signal reproduction processing in this digital signal processing circuit, it is necessary to convert the received intermediate frequency signal into a digital signal. Therefore, an analog-digital conversion circuit is provided in the preceding stage of the digital signal processing circuit. There is.

FIG. 8 is a circuit block diagram showing the structure of an analog-digital conversion circuit of this type which has been conventionally used. In the figure, a reception intermediate frequency signal output from a reception circuit (not shown) is first detected by the low-pass filter 1.
01 is input to the sampling circuit 102 after being band-limited. This sampling circuit 10
2, the low-pass filter 10 according to the sampling clock generated from the clock signal generator 103.
The received signal that has passed 1 is sampled. Then, this sampled received signal is analog-
Input to the digital converter (A / D converter) 104,
After being converted into a digital signal here, it is supplied to a digital signal processing circuit (not shown).

Here, in the preceding stage of the sampling circuit 102
The reason for providing the low pass filter 101 is as follows.
It is a thing. That is, if the bandwidth is not limited,
If the signal is sampled, the sampling circuit
Desired signal from 102Signal after is sampled
And add the sampling frequency to this desired signal frequency
Frequency signalSignal after is sampledAnd desired
Signal obtained by subtracting the sampling frequency from the signal frequencyIs
Signal after being sampledA signal with and superimposed appears
It That is, frequency wrapping occurs. And this
In the state, the above-mentioned signal and the frequency overlap, for example,
When a signal from another radio channel is received, this other radio
The received signal of the channel becomes an interfering wave, which results in A / D conversion.
After the replacement, the desired signal cannot be reproduced. So conventionally,
As described above, the sampling circuit 102 has a low
The low pass filter 1 is provided with the pass filter 101.
01, the sampling frequency is 1/2 or less.
The received signal is filtered at the
Reduce the received signals of other channels that may become harmful waves in advance.
I am trying to weaken.

However, the analog low-pass filter 10
Since 1 is composed of many passive components, it is generally difficult to achieve high-density integration. This is a great obstacle to downsizing the circuit configuration. In addition, the low-pass filter 10
In No. 1, it is difficult to reduce the manufacturing cost because adjustment is required.

[0006]

As described above, in the conventional analog-digital conversion circuit, since the analog low-pass filter 101 is provided in the preceding stage of the sampling circuit 102, the circuit structure can be downsized by the integration and the manufacturing cost can be reduced. It has a problem that it is difficult to reduce.

The present invention has been made in view of the above circumstances, and a first object thereof is to avoid the influence of an interference wave without using a filter for removing an interference wave component. It is an object of the present invention to provide an analog-digital conversion circuit which can always convert a desired signal accurately into a digital signal, and can reduce the size of the circuit configuration and reduce the manufacturing cost.

A second object of the present invention is to provide a filter for removing an interfering wave component,
A / D conversion of a desired signal can be performed without being affected by an interfering wave while the sampling frequency for A / D conversion is fixed, thereby further simplifying and downsizing the circuit configuration. It is to provide an analog-to-digital conversion circuit capable of performing.

[0009]

In order to achieve the first object, the first invention is an analog-digital conversion circuit for converting a desired analog signal having a frequency in an intermediate frequency band into a digital signal. In addition to sampling means for sampling and outputting an analog signal and analog-digital conversion means for converting the signal output from the sampling means into a digital signal, for supplying the sampling signal to the sampling means Variable frequency oscillating means and sampling frequency controlling means. Then, the Ri by the sampling frequency control means, in which the selectively set sampling frequency based on the presence or absence of other analog signals that may be disturbance if example embodiment was as specified in the variable frequency oscillating means.

According to the present invention, the sampling frequency control means is provided with a judging means for judging the presence or absence of an interfering wave whose frequency overlaps with the signal output from the sampling means, and a sampling frequency changing means. When it is determined by the means that there is an interfering wave, the sampling frequency changing means selects a sampling frequency corresponding to another frequency at which the interfering wave is not detected, and designates it to the variable frequency oscillating means.

On the other hand, in order to achieve the above-mentioned second object, a second invention is a base station apparatus equipped with a channel allocation control means for selecting and allocating an appropriate wireless channel from a plurality of wireless channels having different frequencies. In an analog-digital conversion circuit provided in a wireless communication device that performs wireless communication with a sampling signal generating means for generating a sampling signal of a predetermined frequency, and a sampling signal generated by the sampling signal generating means. Sampling means for sampling and outputting a reception intermediate frequency signal of a desired radio channel at a designated timing, and an analog for converting the signal output from this sampling means into a digital signal and subjecting it to predetermined signal processing. In addition to digital conversion means, wireless channel detection means, And a person request sending means. Then, the wireless channel detection means detects a wireless channel corresponding to the frequency of the received intermediate frequency signal in which no interfering wave appears in the frequency range of the signal output from the sampling means, and requests the allocation of this detected wireless channel. The data is transmitted to the channel allocation control means of the base station device.

[0012]

As a result, according to the first aspect of the invention, the sampling is selected so that the desired signal frequency due to the aliasing after sampling does not overlap with other signals which may become interfering waves, based on the existence of other signals. The frequency is set in the sampling means. For this reason, another signal is not superimposed on the desired signal after sampling as an interfering wave, and thus the desired signal after A / D conversion can be reliably reproduced. Further, this eliminates the need for the low-pass filter provided to prevent the superposition of the above-mentioned interfering waves, which makes it possible to reduce the manufacturing cost by simplifying the circuit adjustment including the downsizing of the circuit configuration.

Further, according to the present invention, the determination means determines whether or not there is an interfering wave whose frequency overlaps with the desired signal after sampling, and when the interfering wave is present by this determination, the interfering wave is not detected. The sampling frequency is changed to the frequency of. For this reason, for example, when the use of a wireless channel that has not been communicated until then is started and the interfering wave is received by this, the sampling frequency is automatically changed to another frequency without the interfering wave. Be changed. Therefore, it is possible to prevent the desired signal and the interfering wave from being superposed due to the aliasing after sampling without using a low-pass filter, and thereby to perform a reliable A / D conversion by a small-sized and inexpensive circuit. -A digital conversion circuit can be provided.

On the other hand, according to the second aspect of the present invention, the radio channel corresponding to the received intermediate frequency signal frequency in which the interfering wave does not appear in the frequency of the sampled signal is detected, and the detected radio channel allocation request is issued to the base station. Sent to the device.
Therefore, the mobile station apparatus is assigned a radio channel that is not affected by the interfering wave when the reception intermediate frequency signal is sampled by the A / D conversion circuit. Therefore, the mobile station device does not have a filter for removing an interfering wave component in the front stage of the A / D conversion circuit, and further, the sampling frequency for the A / D conversion is fixed, and the influence of the interfering wave is affected. A of desired signal without receiving
It becomes possible to perform / D conversion. Therefore, not only the filter for removing the interfering wave but also the variable frequency oscillating means for generating the sampling signal can be dispensed with, and the circuit configuration can be further simplified and downsized.

[0015]

【Example】

(First Embodiment) FIG. 1 is a circuit block diagram showing the configuration of a digital portable telephone apparatus equipped with an analog-digital conversion circuit according to the first embodiment of the present invention.

A radio communication signal sent from a base station (not shown) via a radio communication channel is input to a receiving circuit (RX) 3 via an antenna 1 and an antenna duplexer (DUP) 2. In the receiving circuit 3, the wireless communication signal is mixed with the receiving local oscillation signal generated from the frequency synthesizer (SYN) 4 and converted into an intermediate frequency. Further, the receiving circuit 3 is provided with a receiving electric field intensity detector. The received electric field intensity detector detects the signal level of the received intermediate frequency signal, and the detected value RCS of this signal level is transferred to the control circuit 20A. The reception intermediate frequency signal IFS is converted into a digital signal DRS by an analog-digital (A / D) conversion circuit 7 which will be described later, and then input to a digital demodulation circuit (DEM) 6. In the digital demodulation circuit 6, the received signal is frame-synchronized and bit-synchronized, and then signal processing for digital demodulation is performed.

The digital speech signal output from the digital demodulation circuit 6 is an error correction decoding circuit (CH-DE).
C) Error correction decoding is performed in 8. Then, this error-correction-decoded digital speech signal is converted into a voice decoding circuit (SP
-DEC) 9 performs the decoding process, and the D / A converter 10 returns the analog call signal, and then the speaker 1
1 is supplied to the loudspeaker 11 and is output as loudspeaker from the speaker 11.

On the other hand, the transmission signal detected by the microphone 12 is digitized by the A / D converter 13, the acoustic echo component is canceled by the acoustic echo canceller (AEC) 14, and then the voice coding circuit ( SP-COD) 15 is input. In the voice coding circuit 15, the voice coding of the digital transmission signal is performed by a coding system such as the VSELP system. The encoded digital transmission signal obtained by this encoding is
After the error correction code circuit (CH-COD) 16 performs error correction coding together with the digital control signal output from the control circuit 20A, the digital modulation circuit (MOD) 17
Entered in. The digital modulation circuit 17 generates a modulation signal according to the coded digital transmission signal, and the modulation signal is converted into an analog signal by the D / A converter 18 and then input to the transmission circuit (TX) 5. . Transmission circuit 5
Then, after the modulated signal is mixed with the transmission local oscillation signal output from the frequency synthesizer 4 and converted into a radio frequency signal, the transmission power is controlled according to the control signal TCS supplied from the control circuit 20A. The radio frequency signal output from the transmission circuit 5 is transmitted from the antenna 1 to the base station (not shown) via the antenna duplexer 2.

In the apparatus of the present embodiment, among the above circuits, the digital demodulation circuit 6 , the digital modulation circuit 17, the error correction code circuit 8, the error correction decoding circuit 16, the voice decoding circuit 9, the voice code circuit 15 and the acoustic echo canceller. 14
Each function of (1) is realized by a digital signal processing circuit (DSP) 19.

Reference numerals 21 and 24 denote a key input section and a liquid crystal display (LCD), of which the key input section 21 is provided with a transmission key, an end key, a dial key and various function keys. The LCD is used to display the telephone number of the communication partner terminal, the operating state of the device, and the like. Reference numeral 22 denotes a power supply circuit (POW), which generates a required operating voltage Vcc based on the output voltage of the battery 23 and supplies it to the above circuits.

By the way, the A / D conversion circuit 7 and the control circuit 20A for digitizing the received intermediate frequency signal IFS are constructed as follows. FIG. 2 is a circuit block diagram showing the configuration.

[0022] First A / D conversion circuit 7, the sampling circuit 7 1, the signal SRS output from the sampling circuit 7 1 and A / D converter 72 for converting A / D,
It is composed of a sampling clock generator 73. The sampling circuit 71 includes a sampling clock generator 7
The reception intermediate frequency signal output from the reception circuit 3 is sampled in synchronization with the sampling clock SCK generated from the reception circuit 3. The sampling clock generator 73 is composed of a frequency synthesizer and generates a sampling clock SCK having a frequency according to the frequency control signal PR supplied from the control circuit 20A.

On the other hand, the control circuit 20A is provided with a microcomputer as a main control section, and its control function includes a normal control function such as wireless connection control and communication control, a sampling frequency designating means 20a1 and an interfering wave. It has a determination means 20a2.

It is now assumed that the center frequency of the desired signal is FC, the bandwidth of one channel is ± FB, and the sampling frequency is FS. At this time, from the sampling circuit 71 , FC ± FB
A pre-sampled signal with a frequency of
In addition to the signal after, FS + FC ± FB and FS -F
A sampled signal with a frequency of C ± FB is sampled.
The frequency component after pulling is output. The interfering wave determining means 20a2 uses the above FS + FC ± FB and FS -F.
Signal level R of the received intermediate frequency signal IFS in each frequency range of the signal before sampling having a frequency of C ± FB
By comparing CS with a predetermined threshold value Vth, a signal exceeding the threshold value Vth, that is, a sun
After the pulling, the sun becomes the interference wave FU that interferes with the desired signal.
It is determined whether there is a signal before pulling .

The sampling frequency designating means 20a1 is
When setting the sampling frequency, first, a predetermined initial value FS0 is designated to the sampling clock generator 73, and in this state, FS0 + FC ± FB and FS0−FC ± F
From the received intermediate frequency signal IFS in each frequency range of B
It is determined from the determination result of the interference wave determination means 20a2 whether or not the signal which becomes the interference wave FU is detected after the sampling . If no interfering signal is detected after sampling, the initial value FS0 is designated as it is.

On the other hand , when a signal which becomes an interfering wave is detected after sampling, a new frequency FS1 = FS0 + Δf obtained by adding a predetermined shift amount Δf to the initial value FS0 is designated to the sampling clock generator 73. Then, this time, the frequencies of FS1 + FC ± FB and FS1−FC ± FB are included.
From receiving the intermediate frequency signal IFS at each frequency band of sampling the signal before the interference wave FU after sampling to
Comprising signal it is determined whether the detected, after sampling
When a signal that becomes an interfering wave FU is detected at the new frequency FS2 =
FS1 + Δf is designated to the sampling clock generator 73. In the same way, the signal that becomes the interference FU after sampling
No. by shifting the frequency by Δf each time it is detected a new frequency FS3, FS4, ... sequentially specified, where the signal becomes interfere <br/> Gaiha FU after sampling is found sampling frequency is not detected, the Fix to frequency. In addition,
Even if a signal that becomes an interfering wave after sampling is detected after fixing the sampling frequency, the frequency at which the signal that becomes the interfering wave FU is not detected after sampling is detected and specified in the same manner as in the above procedure.

Next, the operation of the circuit configured as described above will be described. When the wireless channel is determined in response to the generation of an outgoing call or an incoming call, the control circuit 20A first sets the initial value FS0 of the sampling frequency to the sampling clock generator 73.
Specify in. At this time, since the sampling clock generator 73 is composed of a frequency synthesizer, the frequency division value PR corresponding to the sampling frequency FS0 is actually designated.

In this state, of the frequency range sampled and output at the sampling frequency FS0, the frequencies FS0 + FC ± FB and FS0-FC ± FB are output.
Presampled signal with number sampled
Received intermediate frequency signal IFS in each frequency range of the latter signal
It is determined whether or not the interfering wave FU is detected.

For example, as shown in FIG. 3, the frequency of the received intermediate frequency signal corresponding to the radio channel, that is, the desired signal frequency Fc is 100 MHz and the channel bandwidth FB is ±.
Initial value FS0 of 10 KHz and sampling frequency is 250
If the frequency is set to MHz, the control circuit 20A has 149.99
MHz to 150.01 MHz and 349.99 MHz
Threshold V in each frequency range of ~ 350.01MHz
signal exceeding th, that is, disturbance FU after sampling
Comprising signal determines whether the detected.

If no interfering signal is detected after sampling in any frequency range as shown in FIG. 3 (b), the sampling circuit 71 thereafter receives the signal at the sampling frequency FS0 = 250 MHz. The frequency signal IFS is sampled. That is, the A / D conversion of the received signal can be performed without being affected by the interfering wave without using the low-pass filter.

On the other hand, during the sampling operation, communication is started, for example, on a wireless channel that has been vacant until then, and the signal on this wireless channel is, for example, 149.99 MHz to 150.01 MHz or 3 as shown in FIG. 3C.
It is assumed that the signal appears at any of 49.99 MHz to 350.01 MHz. Then, the control circuit 20A recognizes this appearing signal as a signal which becomes the interference wave FU after sampling, and sets the sampling frequency FS0 to the new frequency FS1 = FS0.
Change to + Δf.

After this change, similarly to the case of the sampling frequency FS0, it is monitored whether or not the signal which becomes the interfering wave FU is detected after the sampling .
If the interference wave FU is not detected, the sampling frequency FS1 continues to be specified. On the other hand, if an interfering wave is detected even during the sampling operation at the sampling frequency FS1, the sampling frequency FS1 is changed to a new frequency FS2 = FS1 + Δf which is further shifted by Δf. After that, the sampling frequency is shifted each time an interference wave is detected.

As described above, in this embodiment, the interference wave determining means 2a2 causes FS + FC ± FB and FS -FC ± FB.
Monitoring the presence or absence of a signal which becomes interference wave FU after sampling had <br/> Contact to each frequency band of the sampling before the signal having a frequency of, the sampling frequency specifying means 20a1,
The sampling clock generator 73 sets the sampling frequency FS at which no interfering signal is detected after sampling.
With specified to, sampling during the sampling operation
When a signal which becomes an interfering wave is detected after the switching, the sampling frequency is changed to a new frequency shifted by Δf.

Therefore, according to this embodiment, the sump is always
The received intermediate frequency signal IFS can be A / D-converted without being affected by a signal that becomes an interfering wave after ringing , and an accurate A / D-converted output can be obtained. Also sump
Since it is not necessary to provide a low-pass filter for cutting the signal that becomes an interfering wave after ringing in advance, the circuit configuration can be simplified and miniaturized accordingly, and the adjustment of circuit elements can be eliminated. The manufacturing cost can be reduced.

In the above embodiment, when the sampling frequency FS is changed, the sampling frequency FS is sequentially shifted by Δf. However, the frequency is arbitrarily selected and specified within the range of FS ≧ 2 · FC. You may. At this time, the frequency values may be selected in a random order according to a random function generated by the random function generating circuit.

(Second Embodiment) In this embodiment, candidates for the sampling frequency FS are stored in advance in a memory, and when the sampling frequency is initialized and changed, sampling is performed from this memory in a random or fixed order. The frequency FS candidates are read out and designated to the sampling clock generator 73.

FIG. 4 is a circuit block diagram showing the configuration. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof is omitted. A memory circuit (MEM) 25 including a ROM, a RAM, an E ² PROM or a flash memory is attached to the control circuit 20B. The storage circuit 25 stores a plurality of sampling frequency FS candidates, for example, FS1, FS1 + 2 · F,
FS1-2.F, FS1 + 3.F, FS1-3.F, ... Are stored in advance. Here, F corresponds to the channel intervals of a plurality of wireless channels possessed by the mobile phone system.

When the sampling frequency is initially designated or changed, the sampling frequency designating means 20b1 of the control circuit 20B reads the candidates of the sampling frequency FS from the storage circuit 25 sequentially or randomly and designates them to the sampling clock generator 73. . The function of the interfering wave determining means 20b2 is the same as that of the interfering wave determining means 20a2 described in FIG.

With such a configuration, when the sampling frequency FS is designated or changed, the storage circuit 25
It suffices to read the candidates from, and there is no need to perform the calculation each time. Therefore, the sampling frequency can be specified easily and in a short time as compared with the case where the calculation is performed each time. Further, since the sampling frequency candidates stored in advance in the storage circuit 25 are set in correspondence with the wireless channel interval F, the sampling frequency can be designated efficiently.

(Third Embodiment) In this embodiment, a voltage controlled oscillator (VCO) is used as a sampling clock generator, and the sampling frequency FS is used in the control circuit 20C.
By generating control voltage information corresponding to the control voltage information and converting this information into a control voltage by the control voltage generation circuit 26.
O is supplied.

FIG. 5 is a circuit block diagram showing its configuration. In FIG. 5, the same parts as those in FIG. 2 are designated by the same reference numerals. The A / D conversion circuit 70 is provided with a VCO 74 as a sampling clock generator. A control voltage generating circuit 26 is attached to the control circuit 20C. The control circuit 20C uses the sampling frequency designating means 2
0c1, and this sampling frequency designating means 20c1 generates control voltage information as sampling frequency designating information. The control voltage generating circuit 26 is, for example, D /
It is composed of an A converter or a voltage conversion circuit using a pulse width modulation circuit and a smoothing circuit, and generates an analog control voltage VC corresponding to the control voltage information output from the control circuit 20C and supplies it to the VCO 74. The function of the interfering wave determining means 20c2 is the same as that of the interfering wave determining means 20a2 shown in FIG.

Due to such a configuration, the control circuit 20C is used when the sampling frequency FS is designated or changed.
When the sampling frequency FS to be designated is determined, the sampling frequency designating means 20c1 reads the control voltage information corresponding to the sampling frequency FS from the memory table storing the correspondence relationship between the sampling frequency FS and the control voltage information. The control voltage information is supplied to the control voltage generation circuit 26. This control voltage generation circuit 26
Generates an analog control voltage VC according to the control voltage information and supplies it to the VCO 74. Therefore, VCO7
A sampling clock SCK corresponding to the analog control voltage is generated from 4, and the sampling circuit 71 samples the reception intermediate frequency signal IFS according to the sampling clock SCK.

Therefore, according to the present embodiment, the influence of the interfering wave can be avoided without using the low-pass filter as in the first and second embodiments, and the sampling clock generator can be composed of only the VCO. Therefore, the configuration of the A / D conversion circuit can be simplified and downsized as compared with the case where the frequency synthesizer is used as the sampling clock generator.

(Fourth Embodiment) In this embodiment, in a digital automobile / mobile phone system in which a base station device is provided with a radio channel allocation function, a digital mobile phone device as a mobile station is provided with a radio channel detection function. And a channel allocation request sending function, and the wireless channel detection function detects a wireless channel corresponding to the frequency of the received intermediate frequency signal in which no interference wave appears in the frequency range of the signal output from the sampling circuit, and this detection is performed. The wireless channel allocation request is transmitted to the channel allocation function of the base station device.

FIG. 6 is a block diagram showing a main configuration of a digital portable telephone apparatus having such a function. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof is omitted.

The A / D conversion circuit 700 is provided with a sampling clock oscillator 75 which is a fixed oscillator. The sampling clock oscillator 75 generates a sampling clock SCK whose frequency FS is fixedly set in advance. The control circuit 20D has a channel detection means 20d1, an interference wave determination means 20d2, and a channel allocation request transmission means 20d as control functions related to the A / D conversion operation.
3 and 3.

The channel detecting means 20d1 determines the frequency of each wireless channel held by the system and the frequency FS of the sampling clock SCK generated by the sampling clock oscillator 75, prior to the allocation of the wireless channel associated with the incoming and outgoing call. (FS-FC) ± FB and (FS
+ FC) ± FB sampling in each frequency range
This is to detect a radio channel corresponding to FC where a signal which becomes an interfering wave later is not detected.

The interfering wave determining means 20d2 takes in the received electric field intensity detection signal RCS from the receiving circuit 3 when the channel detecting means 20d1 detects FC in which a signal which becomes an interfering wave after sampling is not detected. sampled by comparing the level with a threshold value Vth of the detection signal
The presence or absence of a signal that becomes an interfering wave after ringing is determined.

The channel allocation request transmission means 20d3 generates information for requesting the allocation of the radio channel detected by the channel detection means 20d1 and uses this channel allocation request information together with the transmission request for the control channel. It is transmitted to the base station device.

With such a configuration, when the user makes a transmission operation at the key input unit 21, for example, the control circuit 20D uses the channel detection unit 20d1 while determining the presence or absence of the interference wave by the interference wave determination unit 20d2. (F
Frequency of S-FC) ± FB and (FS + FC) ± FB
In each frequency range of the signal before sampling with
The signal that becomes the interfering wave after sampling is not detected FC
Detect the wireless channel corresponding to. And the sample
When a wireless channel in which no interfering signal is detected is detected after ringing, the channel allocation request sending means 20d3 generates information for requesting the allocation of this wireless channel, and the allocation request information is transmitted together with the transmission request to the control channel. To the base station device via.

On the other hand, when the base station apparatus receives the call request and the channel allocation request information from the mobile station apparatus, it confirms that the radio channel represented by the channel allocation request information is free, and if it is free, A wireless link by this wireless channel is formed with the mobile station device.

Therefore, thereafter, in the A / D conversion circuit 700 of the mobile station device, the reception signal transmitted from the base station device via the radio channel is sampled in the sampling circuit 71, and further digitalized in the A / D converter 72. Will be realized. At this time, the above-mentioned wireless channel is a channel which is confirmed in advance that a signal of another channel does not appear as an interfering wave in the frequency range of the received signal SRS after the sampling. Therefore, the A / D conversion circuit 7
In 00, the received signal is digitized without being affected by the interfering wave, although the low pass filter for removing the interfering wave is not provided and the sampling clock SCK having a fixed frequency is used. You can

Therefore, without using the low-pass filter,
Moreover, since it is not necessary to use a frequency synthesizer for the sampling clock generator, the circuit configuration can be greatly simplified and downsized accordingly.

(Fifth Embodiment) In the present embodiment, a plurality of wireless channels f1 held by the system are periodically or at arbitrary timing during standby.
For each of f2, f3, ..., Fn, (FS-FC)
Service at each frequency range of ± FB and (FS + FC) ± FB
No interfering wave signal is detected after sampling. It is judged whether or not the wireless channel corresponds to FC, and if this judgment detects a wireless channel where no interfering wave signal is detected after sampling , this wireless channel is detected. The channel identification information is stored in the memory. Then, at the time of setting a wireless channel for incoming and outgoing calls, an arbitrary wireless channel is selected from the wireless channels stored in the memory, and a channel allocation request for requesting allocation of this wireless channel is generated to generate a base station. It is designed to be transmitted to the device.

FIG. 7 is a block diagram showing a main configuration of a digital portable telephone device having such a function. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof is omitted.

A memory circuit 27 using, for example, a RAM or a flash memory is attached to the control circuit 20E. The storage circuit 27 is used to store identification information of a radio channel in which a signal interfering with a sampled signal is not detected.

The control circuit 20E has a channel management means 20e1, a channel selection means 20e2, and a channel allocation request transmission means 20e3 as a function for setting a radio channel suitable for A / D conversion.

During standby, the channel management means 20e1 has (FS-FC) ± FB and (FS) for each of the radio channels f1, f2, f3, ..., Fn of the system at regular or random timing. + FC)
It becomes interference wave after the sampling at each frequency range of ± FB
Performs determination of whether the radio channel corresponding to the FC signal is not detected, after sampling this determination
When a radio channel in which a signal that becomes an interfering wave is not detected is detected, the identification information of this radio channel is stored in the storage circuit 27.

The channel selecting means 20e2 selects an empty wireless channel from the wireless channels stored in the storage circuit 27 when a communication request such as an outgoing / incoming call occurs.

The channel allocation request transmission means 20e3 generates information for requesting allocation of the radio channel selected by the channel selection means 20e2, and uses this channel allocation request information together with, for example, a call origination request using the control channel. It is transmitted to the base station device.

With such a configuration, the channel management means 20e1 is provided in the control circuit 20E during the standby period.
, A plurality of radio channels f1, f2, f3, ..., F
A wireless channel capable of A / D conversion without being affected by an interfering wave is detected from among n, and the detected wireless channel is stored in the storage circuit 27. The wireless channel information stored in the storage circuit 27 is updated every time a new detection result is obtained. That is, the memory circuit 2
The latest available wireless channel information is stored in 7.

In this state, for example, when an incoming call request arrives from the base station device, the control circuit 20E confirms the available channel from the wireless channels stored in the memory circuit 27 by the channel selection means 20e2, and then confirms the available channel. Select one. Then, the channel allocation request transmitting means 20
By e3, channel allocation request information for requesting allocation of the selected wireless channel is generated, and this channel allocation request information is sent to the base station apparatus together with the incoming call response information for the incoming call request.

On the other hand, when the base station apparatus receives the incoming call response information and the channel allocation request information from the mobile station apparatus, the base station apparatus confirms that the wireless channel represented by the channel allocation request information is free, and if it is free. For example, a radio link by this radio channel is formed with the mobile station device.

Therefore, thereafter, in the A / D conversion circuit 7 of the mobile station device, the reception signal transmitted from the base station device via the radio channel set by the allocation request is sampled in the sampling circuit 71, and further A / D conversion is performed.
It will be digitized by the D converter 72. At this time, the above-mentioned wireless channel is a channel which is confirmed in advance that a signal of another channel does not appear as an interfering wave in the frequency range of the received signal SRS after the sampling. Therefore, the A / D conversion circuit 700 is not provided with a low-pass filter for removing an interfering wave, and is affected by the interfering wave even though the sampling clock SCK having a fixed frequency is used. The received signal can be digitized without the need.

Further, in this embodiment, since the wireless channel suitable for A / D conversion is previously stored and held in the memory circuit 27, it is not necessary to perform the wireless channel detecting operation every time the communication request is generated. As a result, the wireless channel can be set in a short time.

In the above description, the mobile station device is used as one wireless system (digital automobile / mobile phone system).
However, when using not only one wireless system but also another wireless system having a different frequency band used (for example, PHS), it is determined for each frequency band used by each wireless system. It is necessary to be able to generate each sampling clock frequency.

Therefore, in the device of the fifth embodiment,
The sampling clock generator of the A / D conversion circuit 7 is composed of the variable frequency oscillator 73, and thereby the sampling clock frequency according to each wireless system can be generated. Further, the storage circuit 27 stores and holds, for each wireless system, identification information of a wireless channel that can be A / D converted without being affected by an interfering wave.

Therefore, the device of this embodiment can be applied to a plurality of wireless systems. The present invention is not limited to the above embodiments.
For example, in a system having a function of notifying the use status of the wireless channel held by the system from the base station device to the mobile station device, in the control circuit of the mobile station device, the wireless channel transmitted from the base station device It is also possible to select the sampling frequency Fs at which the signal frequency after sampling and the interfering wave do not overlap with each other based on the information indicating the usage status.

When the sampling frequency FS is determined based on the usage of each radio channel, the sampling frequency FS designation information is output to the sampling clock generator 73 by trial and error in the process of determining the sampling frequency FS. Instead, it is preferable to output the designation information to the sampling clock generator 73 after the sampling frequency FS that can surely avoid the influence of the interference wave is determined. In this way, in the process of determining the sampling frequency FS, the sampling circuit 71 and the A / D converter 72 can be stably operated without destabilizing the operating states.

Further, the frequency synthesizer for generating the sampling clock may be shared with the frequency synthesizer 4 for generating the local oscillation signal. By doing so, the circuit configuration can be further simplified and downsized.

Further, the constituent elements of each of the above-described embodiments may be arbitrarily and selectively combined to form an apparatus having a function equivalent to or different from that of each of the above-described embodiments, which may be used as a new embodiment.

Further, in each of the above-described embodiments, the control circuit performs the designation of the sampling frequency, the determination of the signal which becomes the interference wave after the sampling , the channel management, the transmission control of the channel allocation request, etc. You may do it in. In addition, the sampling frequency is specified and it becomes an interfering wave after sampling.
Various modifications are also made to the control procedures and control contents such as signal determination, channel management, and channel assignment request transmission control, the configuration of the sampling clock generator, the use of the A / D conversion circuit, etc. without departing from the scope of the present invention. Can be implemented.

[0073]

As described above in detail, in the present invention, the sampling means for sampling and outputting the desired analog signal, and the analog-digital conversion for converting the signal output from this sampling means into a digital signal. In addition to the means, a variable frequency oscillating means for supplying a sampling signal to the sampling means,
And a sampling frequency control means, to specify Ri by the sampling frequency control means, the selectively set sampling frequency based on the presence or absence of other analog signals that may be disturbance if example embodiment to the variable frequency oscillation means I have to.

Therefore, according to the present invention, sampling
The influence of the interfering wave can be avoided without using a filter for removing a component which becomes an interfering wave later, whereby the desired signal can always be accurately converted into a digital signal, and the circuit configuration can be downsized and manufactured. It is possible to provide an analog-digital conversion circuit that can reduce cost.

On the other hand, according to the second aspect of the invention, a radio communication apparatus for performing radio communication with a base station apparatus having a channel allocation control means for selecting and allocating an appropriate radio channel from a plurality of radio channels having different frequencies. In the analog-to-digital conversion circuit provided in, a sampling signal generating means for generating a sampling signal of a predetermined frequency and reception of a desired radio channel at a timing specified by the sampling signal generated by the sampling signal generating means. In addition to sampling means for sampling and outputting the intermediate frequency signal and analog-digital converting means for converting the signal output from the sampling means into a digital signal for use in predetermined signal processing, radio channel detection Means and allocation request sending means Then, the wireless channel detection means detects a wireless channel corresponding to the frequency of the received intermediate frequency signal in which no interfering wave appears in the frequency range of the signal output from the sampling means, and requests the allocation of this detected wireless channel. The data is transmitted to the channel allocation control means of the base station device.

Therefore, according to the present invention, sampling
A / D conversion of a desired signal can be performed without being affected by an interference wave without providing a filter for removing a component that becomes an interference wave later and further with a sampling frequency for A / D conversion fixed. Therefore, it is possible to provide an analog-digital conversion circuit which can be further simplified and downsized.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a digital mobile phone device including an analog-digital conversion circuit according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing configurations of an analog-digital conversion circuit and a control circuit shown in FIG.

FIG. 3 is a frequency spectrum diagram used for explaining the operation of the analog-digital conversion circuit shown in FIG.

FIG. 4 is a block diagram showing a configuration of an analog-digital conversion circuit and a control circuit according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an analog-digital conversion circuit and a control circuit according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of an analog-digital conversion circuit and a control circuit according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of an analog-digital conversion circuit and a control circuit according to a fifth embodiment of the present invention.

FIG. 8 is a circuit block diagram showing an example of a configuration of a conventional analog-digital conversion circuit.

[Explanation of symbols]

1 ... Antenna 2 ... Antenna duplexer (DUP) 3 ... Reception circuit (RX) 4 ... Frequency synthesizer (SYN) 5 ... Transmission circuit (TX) 6 ... Digital demodulation circuit (DEM) 7, 70, 700 ... A / D conversion Circuit 8 ... Error correction decoding circuit (CHDEC) 9 ... Voice decoding circuit (SPDEC) 10 ... D / A converter 11 ... Speaker 12 ... Microphone 13 ... A / D converter 14 ... Acoustic echo canceller (AEC) 15 ... Voice code Circuit (SPCOD) 16 ... Error correction code circuit (CHCOD) 17 ... Digital modulation circuit (MOD) 18 ... D / A converter 19 ... Digital signal processing circuit (DSP) 20A, 20B, 20C, 20D, 20E ... Control circuit ( CONT) 20a1, 20b1, 20c1 ... Sample frequency designating means 20a2, 20b2, 20c2, 20d2 ... Interference Wave determining means 20d1 ... Channel detecting means 20e1 ... Channel managing means 20e2 ... Channel selecting means 20d3, 20e3 ... Channel assignment request sending means 21 ... Key input section 22 ... Liquid crystal display (LCD) 23 ... Battery 24 ... Power supply circuit (POW) 25, 27 ... Memory circuit (MEM) 26 ... Control voltage generating circuit 71 ... Sampling circuit 72 ... A / D converter 73 ... Sampling clock generator 74 consisting of variable frequency oscillator ... Voltage controlled oscillator (VCO) 75 ... Fixed frequency oscillator Sampling clock generator consisting of

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Obayashi 1 Komukai Toshiba Town, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Toshiba Research and Development Center (72) Inventor Takashi Amano Komukai Toshiba Town, Kawasaki City, Kanagawa Prefecture No. 1 in Research & Development Center, Toshiba Corporation (56) Reference JP-A-2-218223 (JP, A) JP-A-5-336185 (JP, A) JP-A-6-276129 (JP, A) JP-A 3-231543 (JP, A) JP-A-3-231542 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 1/10 H03M 1/12 H04B 7/26 H04Q 7 / 38

Claims (2)

(57) [Claims] 1. An analog-digital conversion circuit for converting a desired analog signal having a frequency in an intermediate frequency band into a digital signal, and sampling means for sampling and outputting the desired analog signal at a timing designated by a sampling signal. An analog-to-digital conversion means for converting the signal output from the sampling means into a digital signal, a variable frequency oscillating means for supplying the sampling signal to the sampling means in a frequency changeable manner, and after sampling, Analog-to-digital conversion, comprising: sampling frequency control means for designating to the variable frequency oscillating means a sampling frequency selectively set on the basis of the presence of a signal before sampling which becomes an interfering wave circuit 2. Sampling frequency control means, determining means for determining the presence or absence of an interfering wave whose frequency overlaps with the signal output from the sampling means, and when the determining means determines that there is an interfering wave, 2. The analog-digital conversion according to claim 1, further comprising: sampling frequency changing means for selecting a sampling frequency corresponding to another frequency in which no interference wave is detected and designating it as the variable frequency oscillating means. circuit.