WO2022113269A1 - タイムインターリーブ型adc - Google Patents
タイムインターリーブ型adc Download PDFInfo
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M1/08—Continuously compensating for, or preventing, undesired influence of physical parameters of noise
- H03M1/0836—Continuously compensating for, or preventing, undesired influence of physical parameters of noise of phase error, e.g. jitter
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/124—Sampling or signal conditioning arrangements specially adapted for A/D converters
- H03M1/1245—Details of sampling arrangements or methods
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/06—Continuously compensating for, or preventing, undesired influence of physical parameters
- H03M1/0617—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence
- H03M1/0624—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by the use of methods or means not specific to a particular type of detrimental influence by synchronisation
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/1205—Multiplexed conversion systems
- H03M1/121—Interleaved, i.e. using multiple converters or converter parts for one channel
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/1205—Multiplexed conversion systems
- H03M1/121—Interleaved, i.e. using multiple converters or converter parts for one channel
- H03M1/1215—Interleaved, i.e. using multiple converters or converter parts for one channel using time-division multiplexing
Definitions
- the present invention relates to a semiconductor integrated circuit, and particularly to an analog-to-digital converter (ADC).
- ADC analog-to-digital converter
- An analog-to-digital converter (ADC: Analog-to-Digital Converter) is a circuit that periodically acquires (samples) an analog input signal at the timing synchronized with the clock signal, converts it into a digital value, and outputs it.
- ADC Analog-to-Digital Converter
- the ADC 100 samples the analog input signal in at the timing synchronized with the clock signal ck and converts it into the digital output signal out.
- sampling rate fck ⁇ ⁇ ⁇ (1)
- ADCs are used in a wide range of fields such as communication and measurement, but the required sampling rate is also increasing with the increase in communication speed, capacity, and performance of measurement systems.
- As a method of increasing the sampling rate of the ADC there is a method of increasing the clock frequency.
- the clock frequency is increased, there is a problem that the required level in the circuit design for the clock generation circuit and the ADC becomes strict.
- FIG. 10 is a simplified drawing of the configuration disclosed in Non-Patent Document 1.
- each ADC is referred to as a sub-ADC in this document.
- the number of sub-ADCs is called the number of interleaves.
- the number of interleaves is N (N is an integer of 2 or more), and N sub-ADCs 200-1 to 200-N are arranged.
- the analog input signal in is applied to the N sub-ADCs 200-1 to 200-N at the same time.
- the clock signal ck having a period of Tck is applied so that the timing is delayed by ⁇ ck between the sub-ADCs.
- delay circuits 211-1 to 201- (N-1) having a delay time of ⁇ ck are inserted one by one into the clock line between the sub-ADCs.
- the delay circuits 211-1 to 201- (N-1) are realized by, for example, an inverter chain circuit composed of a transistor, a resistor, or the like.
- any one of the sub ADCs 200-1 to 200-N performs sampling. Therefore, the sampling interval of the entire time-interleaved ADC is ⁇ ck. That is, the period of the input clock signal ck is Tck, and while each sub-ADC also operates at the period Tck, sampling can be performed with a period ⁇ ck shorter than Tck in the entire circuit. Therefore, the sampling rate of the time-interleaved ADC is N times the sampling rate of each sub-ADC.
- the digital output signals out-1 to out-N of the sub ADCs 200-1 to 200-N are usually integrated by a digital signal processing circuit or the like in the subsequent stage.
- fs fck ⁇ N ⁇ ⁇ ⁇ (3)
- the time-interleaved ADC it is necessary to increase the number of interleaves N in order to achieve a faster sampling rate fs with respect to the clock frequency fck.
- N sub-ADCs are connected in parallel to the input signal source, so the total input impedance is 1 / N of the input impedance of one sub-ADC, and the total input load is 1. It increases N times in the case of one sub-ADC. For this reason, the time-interleaved ADC has a problem that a large amount of current flows from the input signal source to affect the operation of the input signal source and the input band is narrowed, so that the input characteristics are deteriorated.
- the present invention has been made to solve the above problems, and to provide a time-interleaved ADC capable of maintaining good input characteristics without increasing the load of the input signal source with respect to an increase in the number of interleaves. With the goal.
- the time-interleaved ADC of the present invention is a plurality of ADCs configured to sample an analog input signal and convert it into a digital output signal at a timing synchronized with a clock signal, and an array of the plurality of ADCs in which the analog input signal is used.
- a plurality of first delay circuits configured to give a time difference to the analog input signals so that the analog input signals are sequentially delayed by the first delay time and input to the individual ADCs, and the clock signal of the plurality of ADCs. It is characterized by including a plurality of second delay circuits configured to give a time difference to the clock signal so that they are input to each ADC with a delay of each second delay time in the order of arrangement. ..
- the time-interleaved ADC of the present invention includes a plurality of ADCs configured to sample an analog input signal and convert it into a digital output signal at a timing synchronized with the clock signal, and the plurality of ADCs in which the analog input signal is the plurality of ADCs.
- a plurality of first delay circuits configured to give a time difference to the analog input signals so that they are input to the individual ADCs with a delay of the first delay time in the order of the above, and the clock signal is the analog input. It is characterized by comprising a plurality of second delay circuits configured to give a time difference to the clock signal so that the signals are input to the individual ADCs with a delay of the second delay time in the reverse input order. Is to be.
- the load of the input signal source does not increase with respect to the increase in the number of interleaves, and good input characteristics can be maintained.
- An interleaved ADC can be realized.
- FIG. 1 is a block diagram showing a configuration of a time-interleaved ADC according to a first embodiment of the present invention.
- FIG. 2 is a block diagram showing another configuration of the time-interleaved ADC according to the first embodiment of the present invention.
- FIG. 3 is a block diagram showing a configuration of a time-interleaved ADC according to a second embodiment of the present invention.
- FIG. 4 is a block diagram showing a configuration of a time-interleaved ADC according to a third embodiment of the present invention.
- FIG. 5 is a block diagram showing another configuration of the time interleaved ADC according to the third embodiment of the present invention.
- FIG. 1 is a block diagram showing a configuration of a time-interleaved ADC according to a first embodiment of the present invention.
- FIG. 2 is a block diagram showing another configuration of the time-interleaved ADC according to the first embodiment of the present invention.
- FIG. 3 is
- FIG. 6 is a block diagram showing a configuration of a time-interleaved ADC according to a fourth embodiment of the present invention.
- FIG. 7 is a block diagram showing another configuration of the time interleaved ADC according to the fourth embodiment of the present invention.
- FIG. 8 is a block diagram showing a configuration of a time-interleaved ADC according to a fifth embodiment of the present invention.
- FIG. 9 is a diagram illustrating the operation of the ADC.
- FIG. 10 is a block diagram showing a configuration of a time interleaved ADC.
- FIG. 1 is a block diagram showing a configuration of a time-interleaved ADC according to a first embodiment of the present invention.
- the time-interleaved ADC of this embodiment is N sub-ADC1s (N is an integer of 2 or more) that samples an analog input signal at a timing synchronized with a clock signal and converts it into digital output signals out-1 to out-N.
- the analog input signals are input to the individual sub-ADCs 1-1 to 1-N with a delay of the first delay time ⁇ in in the order of the sub-ADCs 1-1 to 1-N.
- Delay circuits 2-1 to 2- that give a time difference to the input signal, and individual sub-ADC1-1 with a delay of the second delay time ⁇ ck in the order in which the clock signals are arranged in the order of sub-ADC1-1 to 1-N. It is composed of delay circuits 3-1 to 3- (N-1) that give a time difference to the clock signal so as to be input to 1-N.
- the analog input signal in is input to the time interleaved ADC from an input signal source (not shown).
- the clock signal ck is input to the time-interleaved ADC from a clock generation circuit (not shown).
- delay circuits 2-1 to 2- (N-1) are provided between the sub ADCs not only for the clock signal but also for the analog input signal.
- the time be ⁇ ck (i).
- the delay time ⁇ in (i) of each delay circuit 2-i may be a different value or the same value.
- the delay time ⁇ ck (i) of each delay circuit 3-i may be a different value or the same value.
- All delay circuits 2-i and 3-i are designed so that their delay times ⁇ in (i) and ⁇ ck (i) satisfy the following equations.
- 1 / N ⁇ Tck ⁇ ⁇ ⁇ (4)
- N is the number of interleaves and Tck is the clock period.
- ⁇ ck (i) - ⁇ in (i) 1 / N ⁇ Tck ⁇ ⁇ ⁇ (5)
- the relative difference between the delay times of the analog input signal and the clock signal is 1 / N ⁇ Tck in each of the sub ADCs 1-2 to 1-N.
- a sampling rate N times the clock frequency can be obtained.
- the feature of this embodiment is that the input signal source only needs to drive the sub-ADC1-1 and the delay circuit 2-1 of the first stage regardless of the number of interleaves N. That is, unlike the conventional time-interleaved ADC, the load of the input signal source does not increase even if the number of interleaves N increases. Further, each delay circuit 2-i only needs to drive the sub ADC1- (i + 1) and the delay circuit 2- (i + 1) of the next stage. Therefore, the time-interleaved ADC of this embodiment can maintain good input characteristics even if the number of interleaves N increases.
- an input buffer may be provided between the input signal source that outputs the analog input signal in and the analog input signal terminal of the sub-ADC1-1 of the first stage.
- the configuration in this case is shown in FIG. In the case of the configuration of FIG. 2, the input signal source need only drive the input buffer 4.
- the first embodiment has the following problems.
- the number of interleaves N and the value of the clock period Tck are determined by the determined specifications. Therefore, the delay circuits 2-i, 3- The delay times ⁇ in (i) and ⁇ ck (i) of i may be determined.
- the problem of the first embodiment is that the delay time ⁇ ck (i) of the delay circuit 3-i is longer by ⁇ in (i) than the delay time 1 / N ⁇ Tck of the conventional delay circuit 201-i. ..
- characteristics such as circuit delay time vary depending on the accuracy of circuit manufacturing technology, temperature fluctuations during operation, fluctuations in power supply voltage, and the like. For example, even if the variation is 1% or 3%, the longer the delay time ⁇ ck (i), the larger the absolute value of the variation.
- the delay time variation of the delay circuit 3-i becomes large, it causes a sampling timing error of each sub-ADC. That is, the input signal is sampled at a timing deviated from the time when the analog input signal should be sampled, and an error is superimposed on the output waveform by the amount deviated from the timing. The larger the timing error, the larger the error in the output waveform, and the worse the performance as an ADC.
- FIG. 3 is a block diagram showing a configuration of a time-interleaved ADC according to the present embodiment.
- the time-interleaved ADC of this embodiment has sub-ADCs 1-1 to 1-N, delay circuits 2-1 to 2- (N-1), and a second clock signal in the reverse input order of the analog input signal. It is composed of delay circuits 5- (N-1) to 5-1 that give a time difference to the clock signals so that they are input to the individual sub-ADCs 1-N to 1-1 with a delay time of ⁇ ck.
- the analog input signal is input in the order of sub ADC1-1, 1-2, ..., 1-N as in the first embodiment.
- the clock signal is input in the order of sub ADC1-N, ..., 1-2, 1-1. That is, the difference from the first embodiment is that the order of input to each sub-ADC is reversed between the analog input signal and the clock signal.
- the delay time of the delay circuit 5- (i) between the sub ADC1-i and the sub ADC1- (i + 1) is defined as ⁇ ck (i).
- the delay time ⁇ ck (i) of each delay circuit 5-i may be a different value or the same value.
- a sampling rate of N times the clock frequency is obtained as in the conventional time-interleaved ADC and the first embodiment. be able to.
- the feature of this embodiment is that the delay time ⁇ ck (i) of the delay circuit 5-i is set to a value shorter than the delay time 1 / N ⁇ Tck of the conventional delay circuit 201-i. There is a point that can be done. Therefore, in this embodiment, the error in the delay time of the delay circuit 5-i can be reduced as compared with the conventional time-interleaved ADC and the first embodiment. As a result, it is possible to design a highly accurate ADC.
- an input buffer may be provided between the input signal source and the analog input signal terminal of the sub-ADC1-1 of the first stage.
- the delay circuit of either the analog input signal or the clock signal, or the delay of both the analog input signal and the clock signal it is conceivable to make the delay time in the circuit variable by inputting a control signal from the outside. By making the delay time variable, it is possible to calibrate the variation in the delay time in the usage state after the circuit is manufactured.
- FIG. 4 is a block diagram showing a configuration of a time-interleaved ADC according to a third embodiment of the present invention.
- the time-interleaved ADC of this embodiment is composed of sub-ADCs 1-1 to 1-N and variable delay circuits 2a-1 to 2a- (N-1) and 3a-1 to 3a- (N-1). To.
- the delay circuits 2-1 to 2- (N-1) are replaced with the variable delay circuits 2a-1 to 2a- (N-1) in the first embodiment, and the delay circuits 3-1 to 3 are used.
- -(N-1) is replaced with variable delay circuits 3a-1 to 3a- (N-1).
- the delay time ⁇ in (i) of the variable delay circuit 2a-i between the sub-ADC1-i (i is an integer of 1 to (N-1)) and the sub-ADC1- (i + 1) is the delay control signal ctrl_ ⁇ in (i). ) Can be adjusted. Similarly, the delay time ⁇ ck (i) of the variable delay circuit 3a-i can be adjusted by the delay control signal ctrl_ ⁇ ck (i).
- FIG. 5 shows the configuration when this embodiment is applied to the second embodiment.
- the delay circuits 2-1 to 2- (N-1) are replaced with the variable delay circuits 2a-1 to 2a- (N-1), and the delay circuits 5- (N-) are replaced.
- 1) to 5-1 are replaced with variable delay circuits 5a- (N-1) to 5a-1.
- the delay time of both the analog input signal and the clock signal delay circuit is variable, but the delay circuit of only one of the analog input signal and the clock signal may be a variable delay circuit. good.
- an input buffer may be provided between the input signal source and the analog input signal terminal of the sub-ADC1-1 of the first stage.
- the analog input signals input to the individual sub-ADCs must all have the same waveform except that they have different time delays. That is, the gains of the delay circuits of the analog input signal should all be 1.
- the gain error is integrated as the analog input signal input to the sub-ADC in the subsequent stage, and the noise superimposed on the output signal is large.
- the gain (amplification factor) of the delay circuit variable so that the gain mismatch between the sub-ADCs can be calibrated to some extent.
- FIG. 6 is a block diagram showing a configuration of a time-interleaved ADC according to a fourth embodiment of the present invention.
- the time-interleaved ADC of this embodiment includes sub-ADCs 1-1 to 1-N and delay circuits 2b-1 to 2b- (N-1) whose gain can be adjusted by a gain control signal input from the outside. It is composed of delay circuits 3-1 to 3- (N-1).
- the delay circuits 2-1 to 2- (N-1) are replaced with the delay circuits 2b-1 to 2b- (N-1) in the first embodiment.
- the gain of the delay circuit 2b-i between the sub-ADC1-i (i is an integer of 1 to (N-1)) and the sub-ADC1- (i + 1) can be adjusted by the gain control signal ctrl_g (i). It is possible.
- the delay circuit 2bi can be realized by a combination of a delay circuit composed of, for example, an inverter chain circuit and a variable gain amplifier.
- FIG. 7 shows a configuration when this embodiment is applied to the second embodiment.
- the delay circuits 2b-1 to 2b- (N-1) may be a delay circuit having a variable delay and a variable gain. Further, the delay circuits 3-1 to 3- (N-1) and 5-1 to 5- (N-1) may be variable delay circuits. Further, as in the first embodiment, an input buffer may be provided between the input signal source and the analog input signal terminal of the sub-ADC1-1 of the first stage.
- the analog input signals are delay circuits 2-1 to 2- (N-1), 2a-1 to 2a- (N-1), 2b-1 to 2b- (N-1). ). Therefore, the output signals out-1 to out-N of the individual sub ADCs 1-1 to 1-N are the delay circuits 2-1 to 2- (N-1) and 2a-1 to 2a- (N-1). , 2b-1 to 2b- (N-1) are output at relatively different timings by the delay time. Due to the timing shift of the output signals out-1 to out-N, the processing of the digital signal processing circuit that integrates the output signals out-1 to out-N becomes complicated. In order to simplify the processing of the digital signal processing circuit, it is conceivable to provide a delay circuit for correcting the time difference between the output signals out-1 to out-N at the output of each sub-ADC.
- FIG. 8 is a block diagram showing a configuration of a time-interleaved ADC according to a fifth embodiment of the present invention.
- the time-interleaved ADCs of this embodiment include sub-ADCs 1-1 to 1-N, delay circuits 2-1 to 2- (N-1), 3-1 to 3- (N-1), and sub-ADC1-. It is provided for each of the outputs 1 to 1-N, and is composed of delay circuits 6-1 to 6-N that correct the time difference between the output signals out-1 to out-N of the sub ADCs 1-1 to 1-N.
- the sub-ADC1-2 receives an analog input signal delayed by ⁇ in (1) from the sub-ADC1-1. Therefore, the output signal out-2 of the sub-ADC1-2 is delayed by ⁇ in (1) from the output signal out-1 of the sub-ADC1-1. Therefore, delay circuits 6-1 and 6-2 are provided for the outputs of the sub-ADCs 1-1 and 1-2, respectively, and the delay time of the output of the sub-ADC1-1 is longer than the delay time of the output of the sub-ADC1-2 by ⁇ in (1). ), The outputs of the sub ADCs 1-1 and 1-2 can be processed on the same time axis.
- the delay circuit 6 so as to satisfy the following conditions for all integers M of 2 or more and N or less. Design -1 to 6-N.
- ⁇ out (1) is the delay time of the delay circuit 6-1 connected to the output of the sub-ADC1-1
- ⁇ out (M) is the delay circuit connected to the output of the sub-ADC1-M (M is an integer of 2 to N). It is a delay time of 6-M.
- delay circuits 6-1 to 6-N may be provided in the second to fourth embodiments.
- an input buffer may be provided between the input signal source and the analog input signal terminal of the sub-ADC1-1 of the first stage.
- the analog input signal and the clock signal are each a single-phase signal, but either one of the analog input signal and the clock signal, or both the analog input signal and the clock signal are used as differential signals. May be good. This is expected to improve the signal-to-noise ratio by removing common-mode noise.
- the delay circuits 2-1 to 2- (N-1), 2a-1 to 2a- (N-1), and 2b-1 to 2b- (N-1) are different. It is a dynamic input differential output type delay circuit.
- the sub ADCs 1-1 to 1-N are differential input type ADCs.
- the delay circuits 3-1 to 3- (N-1), 3a-1 to 3a- (N-1), 5-1 to 5- (N-1), 5a- 1 to 5a- (N-1) are differential input differential output type delay circuits.
- the sub ADCs 1-1 to 1-N are differential clock input type ADCs.
- the present invention can be applied to ADC.
- Sub ADC 2-1 to 2- (N-1), 2b-1 to 2b- (N-1), 3-1 to 3- (N-1), 5-1 ⁇ 5- (N-1), 6-1 ⁇ 6-N ...
- Delay circuit 2a-1 ⁇ 2a- (N-1), 3a-1 ⁇ 3a- (N-1), 5a-1 ⁇ 5a- (N-1) ...
- Variable delay circuit 4 ... Input buffer.
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Abstract
Description
fs=fck ・・・(1)
ADCのサンプリングレートを高速化する方法としては、クロック周波数を上げる方法がある。しかしながら、クロック周波数を上げると、クロック生成回路やADCに対する回路設計上の要求水準が厳しくなるという問題がある。
τck=1/N×Tck ・・・(2)
以上のタイムインターリーブ型ADCの動作について説明する。サブADC200-1がアナログ入力信号inをサンプリングする時刻を0とすると、サブADC200-2にはサブADC200-1よりもτckだけ遅れたクロック信号が印加される。したがって、サブADC200-2は、時刻τckにおいてアナログ入力信号inのサンプリングを行う。そして、時刻N×τck=Tckにおいて、再びサブADC200-1がサンプリングを行う。
以上の話を一般化すると、タイムインターリーブ型ADCでは、サンプリングレートをfs、クロック周波数をfck=1/Tckとすると、次式が成立する。
fs=fck×N ・・・(3)
以下、本発明の実施例について図面を参照して説明する。図1は本発明の第1の実施例に係るタイムインターリーブ型ADCの構成を示すブロック図である。本実施例のタイムインターリーブ型ADCは、クロック信号に同期したタイミングでアナログ入力信号をサンプリングしてデジタル出力信号out-1~out-Nに変換するN個(Nは2以上の整数)のサブADC1-1~1-Nと、アナログ入力信号がサブADC1-1~1-Nの並び順に第1の遅延時間τinずつ遅れて個々のサブADC1-1~1-Nに入力されるように、アナログ入力信号に時間差を与える遅延回路2-1~2-(N-1)と、クロック信号がサブADC1-1~1-Nの並び順に第2の遅延時間τckずつ遅れて個々のサブADC1-1~1-Nに入力されるように、クロック信号に時間差を与える遅延回路3-1~3-(N-1)とから構成される。
|τin(i)-τck(i)|=1/N×Tck ・・・(4)
τck(i)-τin(i)=1/N×Tck ・・・(5)
自明であるが、全てのiについてτin(i)=0とすれば、図10に示した従来のタイムインターリーブ型ADCと等価な構成となり、式(4)は式(2)と一致する。
第1の実施例には、次に述べる問題がある。所望のサンプリングレートを達成するタイムインターリーブ型ADCを設計する場合、決定した仕様によってインターリーブ数Nとクロック周期Tckの値が決まるので、式(5)が成立するように遅延回路2-i,3-iの遅延時間τin(i),τck(i)を決定すればよい。
一般的に回路の遅延時間等の特性は、回路の製造技術の精度や、動作中の温度の変動、電源電圧の変動等によってばらつく。例えば1%、3%といったばらつきであっても、遅延時間τck(i)が長くなれば、ばらつきの絶対値も大きくなる。
τin(i)+τck(i)=1/N×Tck ・・・(6)
なお、第1の実施例と同様に、入力信号源と初段のサブADC1-1のアナログ入力信号端子との間に入力バッファを設けるようにしてもよい。
第2の実施例で述べた遅延時間のばらつきに関しては、第1、第2の実施例共に、アナログ入力信号とクロック信号のどちらか一方の遅延回路、あるいはアナログ入力信号とクロック信号の両方の遅延回路における遅延時間を外部からの制御信号入力により可変にするという対応が考えられる。遅延時間を可変にすることにより、回路製造後の使用状態において遅延時間のばらつきを校正することができる。
また、第1の実施例と同様に、入力信号源と初段のサブADC1-1のアナログ入力信号端子との間に入力バッファを設けるようにしてもよい。
第1~第3の実施例では、個々のサブADCに入力されるアナログ入力信号は、それぞれ異なる時間遅れがあることを除いて全て同じ波形である必要がある。すなわち、アナログ入力信号の遅延回路の利得は全て1であるべきである。しかし、個々の遅延回路の利得が回路のばらつきの影響によりずれた場合、後段のサブADCに入力されるアナログ入力信号ほど、利得の誤差が積算されていき、出力信号に重畳される雑音が大きくなる。このような遅延回路の利得のばらつきに関しては、遅延回路の利得(増幅率)を可変にしてサブADC間の利得のミスマッチをある程度校正できるようにするという対応が考えられる。
サブADC1-i(iは1~(N-1)の整数)とサブADC1-(i+1)との間にある遅延回路2b-iの利得は、利得制御信号ctrl_g(i)によって調整することが可能である。遅延回路2b-iは、例えばインバータチェーン回路等から構成される遅延回路と可変利得増幅器の組み合わせによって実現することができる。
本実施例を第2の実施例に適用した場合の構成を図7に示す。
また、第1の実施例と同様に、入力信号源と初段のサブADC1-1のアナログ入力信号端子との間に入力バッファを設けるようにしてもよい。
第1~第4の実施例では、アナログ入力信号が遅延回路2-1~2-(N-1),2a-1~2a-(N-1),2b-1~2b-(N-1)を通っている。このため、個々のサブADC1-1~1-Nの出力信号out-1~out-Nは、遅延回路2-1~2-(N-1),2a-1~2a-(N-1),2b-1~2b-(N-1)の遅延時間分だけ、相対的にずれたタイミングで出力される。出力信号out-1~out-Nのタイミングのずれにより、出力信号out-1~out-Nを統合するデジタル信号処理回路の処理が複雑になる。デジタル信号処理回路の処理を簡潔にするために、出力信号out-1~out-Nの時間差を補正する遅延回路を各サブADCの出力に設けるという対応が考えられる。
こうして、本実施例では、サブADC1-1~1-Nの出力信号out-1~out-Nを同じ時間軸上で処理することができるため、後段の処理が簡潔になる。
また、第1の実施例と同様に、入力信号源と初段のサブADC1-1のアナログ入力信号端子との間に入力バッファを設けるようにしてもよい。
Claims (5)
- クロック信号に同期したタイミングでアナログ入力信号をサンプリングしてデジタル出力信号に変換するように構成された複数のADCと、
前記アナログ入力信号が前記複数のADCの並び順に第1の遅延時間ずつ遅れて個々のADCに入力されるように、前記アナログ入力信号に時間差を与えるように構成された複数の第1の遅延回路と、
前記クロック信号が前記複数のADCの並び順に第2の遅延時間ずつ遅れて個々のADCに入力されるように、前記クロック信号に時間差を与えるように構成された複数の第2の遅延回路とを備えることを特徴とするタイムインターリーブ型ADC。 - クロック信号に同期したタイミングでアナログ入力信号をサンプリングしてデジタル出力信号に変換するように構成された複数のADCと、
前記アナログ入力信号が前記複数のADCの並び順に第1の遅延時間ずつ遅れて個々のADCに入力されるように、前記アナログ入力信号に時間差を与えるように構成された複数の第1の遅延回路と、
前記クロック信号が前記アナログ入力信号と逆の入力順で第2の遅延時間ずつ遅れて個々のADCに入力されるように、前記クロック信号に時間差を与えるように構成された複数の第2の遅延回路とを備えることを特徴とするタイムインターリーブ型ADC。 - 請求項1または2記載のタイムインターリーブ型ADCにおいて、
前記第1の遅延回路と前記第2の遅延回路のうち少なくとも一方は、外部から入力される遅延制御信号により遅延時間の調整が可能であることを特徴とするタイムインターリーブ型ADC。 - 請求項1乃至3のいずれか1項に記載のタイムインターリーブ型ADCにおいて、
前記第1の遅延回路は、外部から入力される利得制御信号により利得の調整が可能であることを特徴とするタイムインターリーブ型ADC。 - 請求項1乃至4のいずれか1項に記載のタイムインターリーブ型ADCにおいて、
前記複数のADCの出力にそれぞれ設けられ、前記複数のADCの出力信号の時間差を補正するように構成された複数の第3の遅延回路をさらに備えることを特徴とするタイムインターリーブ型ADC。
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JP2008245002A (ja) * | 2007-03-28 | 2008-10-09 | Anritsu Corp | A/d変換装置 |
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US20150303934A1 (en) * | 2014-04-17 | 2015-10-22 | The Board Of Regents, The University Of Texas System | System and method for dynamic path-mismatch equalization in time-interleaved adc |
US20170005640A1 (en) * | 2015-07-03 | 2017-01-05 | Rohde & Schwarz Gmbh & Co. Kg | Delay line system, high frequency sampler, analog-to-digital converter and oscilloscope |
US20200244279A1 (en) * | 2019-01-24 | 2020-07-30 | Analog Devices, Inc. | Distributed adc for enhanced bandwidth and dynamic range |
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JP2013535943A (ja) * | 2010-08-17 | 2013-09-12 | 日本テキサス・インスツルメンツ株式会社 | 調整可能な帯域幅を備えたトラックアンドホールドアーキテクチャ |
US20150303934A1 (en) * | 2014-04-17 | 2015-10-22 | The Board Of Regents, The University Of Texas System | System and method for dynamic path-mismatch equalization in time-interleaved adc |
US20170005640A1 (en) * | 2015-07-03 | 2017-01-05 | Rohde & Schwarz Gmbh & Co. Kg | Delay line system, high frequency sampler, analog-to-digital converter and oscilloscope |
US20200244279A1 (en) * | 2019-01-24 | 2020-07-30 | Analog Devices, Inc. | Distributed adc for enhanced bandwidth and dynamic range |
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