JP2008216027A - Signal recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately record and reproduce a broadcasting signal by automatically performing adjustment so that the output level of the recorded broadcasting signal does not exceed a dynamic range of AD conversion when the broadcasting signal is AD converted and recorded, and returning the output level to the output level before the adjustment when the recorded broadcasting signal is reproduced. <P>SOLUTION: In recording the signal, the output level of the signal received by a signal receiving section 11 is detected by an output level setting section 12, amplification or attenuation is performed by a recorded signal amplification section 13 to adjust the output level so that the output level of a recorded signal frequency conversion section 14 does not exceed a dynamic range of an AD conversion section 15, and the gain of the recorded signal amplification section 13, namely the signal and the adjustment amount of signal, is recorded on a recording section 110. In reproducing the signal, the amplification or attenuation of the signal recorded on the recording section is performed by a reproduced signal amplification section 22 based on the gain recorded on the recording section 110, and the output level is returned to the output level before the adjustment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a signal recording / playback apparatus.

When evaluating the performance of a receiver developed for various broadcast signals, field tests in a moving environment of the vehicle are an important item, particularly when the receiver is mounted on the vehicle. However, this field test requires enormous time and man-hours for preparation and evaluation, and even when the same field test is performed, reproducibility is difficult to maintain, and the same evaluation result may not be obtained. There was a point. In order to solve this problem, there has been proposed a signal recording / reproducing apparatus that can once reproduce a broadcast signal under a mobile environment in a laboratory once the broadcast signal is acquired under the mobile environment (patent) References 1, 2).
Japanese Patent Laid-Open No. 6-265587 JP 11-183544 A

  By the way, in such a signal recording / playback apparatus, it is common to record a broadcast signal by AD conversion. However, if the output level of the broadcast signal exceeds the dynamic range of AD conversion, the AD conversion value is saturated. It becomes impossible to record the original signal faithfully. For this reason, a signal recording / reproducing apparatus that detects the output level of a broadcast signal and records the output level after attenuating the output level by a predetermined amount with an attenuator when the detected output level exceeds the dynamic range of AD conversion is conceivable.

  However, in such a signal recording / playback apparatus, if the output level of the broadcast signal is attenuated by a predetermined amount by an attenuator and the dynamic range of AD conversion is exceeded, there remains a problem that recording cannot be performed. In addition, since the amount of attenuation of the output level by the attenuator is fixed, if the output level of the broadcast signal slightly exceeds the dynamic range of AD conversion, the output level is attenuated more than necessary. There is a problem that the dynamic range of conversion cannot be used efficiently.

  It is an object of the present invention to detect the output level of a received broadcast signal when recording a broadcast signal by AD conversion, and automatically so that the output level of the broadcast signal to be recorded does not exceed the dynamic range of AD conversion. When adjusting and recording with the adjustment amount and playing back the recorded broadcast signal, DA conversion is performed on the recorded broadcast signal and adjustment amount, and the output level of the broadcast signal is set to the output level before output level adjustment based on the adjustment amount. The object is to propose a signal recording / reproducing apparatus for recording and reproducing broadcast signals with high accuracy.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a signal recording / reproducing apparatus that performs AD conversion and recording of a radio frequency signal and DA-converts and reproduces the recorded radio frequency signal. When recording a frequency signal, detect the output level of the received radio frequency signal, adjust the output level so that the output level of the recorded radio frequency signal does not exceed the dynamic range of the AD conversion, The radio frequency signal whose output level has been adjusted and the adjustment amount of the output level are AD-converted with a sampling clock signal generated based on a predetermined reference signal, recorded together with the reference signal, and the recorded radio frequency signal is reproduced. When performing the sampling, the recorded radio frequency signal and the adjustment amount are generated based on the reference signal. And DA conversion on the basis of the lock signal, is characterized by playing back the output level of the radio frequency signal to the output level before the adjustment based on the adjustment amount.

  According to the above configuration, when a broadcast signal is recorded after AD conversion, the output level of the recorded broadcast signal is automatically adjusted so as not to exceed the dynamic range of AD conversion, and the recorded broadcast signal is reproduced. In addition, the broadcast signal can be recorded and reproduced with high accuracy by returning to the output level before the output level adjustment.

  According to a second aspect of the present invention, a signal receiving unit that receives a radio frequency signal, and an output level of the radio frequency signal received by the signal receiving unit are detected, and the radio frequency signal is detected based on the output level. An output level setting unit for calculating a gain at the time of amplification, a recorded signal amplifying unit for amplifying the radio frequency signal based on the gain calculated by the output level setting unit, and the radio amplified by the recorded signal amplifying unit A recording signal frequency conversion unit that performs frequency conversion of a frequency signal, a recording signal processing unit having the frequency signal converted by the recording signal frequency conversion unit, and the gain calculated by the output level setting unit An AD conversion unit that performs AD conversion using a sampling clock signal generated based on a reference signal, and the radio frequency signal and AD converted by the AD conversion unit A recording control unit that outputs the gain and the reference signal as recording data; and a recording unit that records the recording data output by the recording control unit; and Reading the recorded data recorded in the recording unit and separating the radio frequency signal and the gain and the reference signal into a reproduction control unit; and the radio frequency signal and the gain separated by the reproduction control unit as the reference signal A DA converter that performs DA conversion based on the sampling clock signal generated based on the radio frequency, and the radio that is DA-converted by the DA converter based on the gain DA-converted by the DA converter. A reproduction signal amplification unit that amplifies a frequency signal, and a reproduction signal frequency conversion unit that performs frequency conversion of the radio frequency signal amplified by the reproduction signal amplification unit It is characterized by comprising a signal reproduction portion and a reproduction signal processing unit having a.

  According to a third aspect of the present invention, in the second aspect, the output level setting unit is configured such that the output level of the radio frequency signal frequency-converted by the recorded signal frequency conversion unit does not exceed the dynamic range of the AD conversion unit. The gain is set as described above.

  According to a fourth aspect of the present invention, in the second or third aspect, the reproduction signal amplifying unit is configured to input the radio frequency signal in which an output level of the radio frequency signal after amplification is input to the recorded signal amplifying unit. The radio frequency signal is amplified so as to be equal to the level.

  According to the above configuration, when a broadcast signal is recorded after AD conversion, the output level of the recorded broadcast signal is automatically adjusted so as not to exceed the dynamic range of AD conversion, and the recorded broadcast signal is reproduced. In addition, the broadcast signal can be recorded and reproduced with high accuracy by returning to the output level before the output level adjustment.

  When the broadcast signal is recorded after AD conversion, the output level of the received broadcast signal is detected and automatically adjusted so that the output level of the recorded broadcast signal does not exceed the dynamic range of AD conversion. When recording and playing back the recorded broadcast signal, the recorded broadcast signal and adjustment amount are DA converted, and the broadcast signal output level is returned to the output level before output level adjustment based on the adjustment amount. Can be recorded and reproduced with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic block diagram of an embodiment of the present invention.

  The signal recording / playback apparatus according to the embodiment of the present invention includes a signal recording unit 100 and a signal playback unit 200.

  The signal recording unit 100 includes a receiving antenna 101, a recorded signal processing unit 102, a recording unit 103, and a recording unit 110.

  The broadcast signal received by the receiving antenna 101 is input to the recorded signal processing unit 102 as the received signal SR01.

  The recording signal processing unit 102 adjusts the output level of the reception signal SR01 so that the recording signal SR02 output by the recording signal processing unit 102 does not exceed the dynamic range of AD conversion (described later) performed by the recording unit 103. Output level control is performed, and frequency conversion (described later) to an intermediate frequency, which is common in radio frequency signal processing, is performed. Further, a control signal for output level control is output as a recording gain control signal SR03.

  The recording unit 103 takes in the recording signal SR02 and the recording gain control signal SR03 output from the recording signal processing unit 102, performs AD conversion, and records them as recording data SR04 in the recording unit 110.

  The signal reproduction unit 200 includes a reproduction unit 201 and a reproduction signal processing unit 202.

  The reproducing unit 201 reads the recorded data SR04 recorded in the recording unit 110 as the reproduced data SP01, separates the recorded signal SR02 and the recorded gain control signal SR03, and DA-converts each to reproduce the reproduced IF signal SP02 and the reproduced gain control signal. The signal is output to the reproduction signal processing unit 202 as SP03.

  The reproduction signal processing unit 202 returns the output level of the reproduction IF signal SP02 to the output level before adjusting the output level based on the reproduction gain control signal SP03, and converts the frequency to a high frequency that is common in radio frequency signal processing ( To be output as a reproduction RF signal SP04.

  The reproduction RF signal SP04 output from the reproduction signal processing unit 202 is input to the receiver under test 300, and an evaluation test is performed.

  Next, this embodiment will be described in detail with reference to FIGS.

  First, a description will be given of a signal recording operation for capturing a broadcast signal and automatically adjusting and recording the output level of the broadcast signal so as not to exceed the dynamic range of AD conversion.

  FIG. 2 shows a detailed block diagram of the recorded signal processing unit 102.

  The recorded signal processing unit 102 includes a reception antenna 101, a band-pass filter 111 (described as BPF 111 in FIG. 2), a signal reception unit 11 including an amplification unit 112, an output level detection unit 113, and an output level control unit 114. Recorded signal amplifying unit 13 including output level setting unit 12, variable gain amplifying unit 115, band pass filter 116 (described as BPF 116 in FIG. 2), frequency converting unit 117, band pass filter 118 (FIG. 2). In FIG. 2, the recording signal frequency conversion unit 14 includes an amplification unit 119 and a low-pass filter 11A (described as LPF 11A in FIG. 2).

  The broadcast signal received by the reception antenna 101 is input to the bandpass filter 111 as the reception signal SR01, and an unnecessary frequency band is cut, and the band-limited RF signal SR11 is output.

  The RF signal SR11 is input to the amplifying unit 112, subjected to predetermined signal amplification, and output as the RF signal SR12.

  The RF signal SR12 is input to the variable gain amplifier 115 and also input to the output level detector 113.

  The output level detector 113 detects the output level of the input RF signal SR12, and outputs an output level signal SR13 indicating the detected output level.

  The output level signal SR13 is input to the output level control unit 114. When the RF signal SR12 is amplified by the variable gain amplifying unit 115, the output level control unit 114 sets the output level of the recording signal SR02 output from the recording signal frequency conversion unit 14 to the dynamics of the AD conversion unit 11B of the recording unit 103 described later. The gain control signal SR14 is set based on the output level signal SR13 so as not to exceed the range, and is output.

  The gain control signal SR14 is input to the variable gain amplifying unit 115 and input to the recording unit 103 (described later). The variable gain amplifier 115 amplifies or attenuates the RF signal SR12 based on the gain control signal SR14, and outputs the amplified RF signal SR15. The output RF signal SR15 is amplified or attenuated so that the output level of the recording signal SR02 output by the recording signal frequency conversion unit 14 does not exceed the dynamic range of the AD conversion unit 11B of the recording unit 103.

  The RF signal SR15 is input to the bandpass filter 116, unnecessary frequency bands are cut, and the band-limited RF signal SR16 is output.

  The RF signal SR16 is input to the mixer 117B provided in the frequency conversion unit 117. The mixer 117B also receives a predetermined oscillation signal SR17 output from the local oscillator 117A included in the frequency converter 117, and the mixer 117B performs frequency conversion of the RF signal SR16 based on the oscillation signal SR17 (so-called intermediate frequency). Conversion) and output as IF signal SR18.

  The IF signal SR18 is input to the bandpass filter 118, and an unnecessary noise signal generated by frequency conversion is cut and output as a band-limited IF signal SR19.

  The IF signal SR19 is input to the amplifying unit 119, subjected to predetermined signal amplification, and output as the IF signal SR1A.

  The IF signal SR1A is input to the low-pass filter 11A, unnecessary harmonics are cut, and output to the recording unit 103 as the recording signal SR02.

  FIG. 3 shows a detailed block diagram of the recording unit 103.

  The recording unit 103 includes an AD conversion unit 15 including an AD conversion unit 11B, an AD conversion unit 11C, and a sampling clock generation unit 11D (described as SCLK generation unit 11D in FIG. 3), and a recording control unit 11E. .

  The recording signal SR02 is input to the AD conversion unit 11B. The gain control signal SR03 is input to the AD conversion unit 11C.

  Here, the recording control unit 11E outputs a sampling clock control signal SR1D (described as SCLK control signal SR1D in FIG. 3), which is a reference signal, to the sampling clock generation unit 11D.

  The sampling clock generator 11D generates a sampling clock signal SR1E (described as SCLK signal SR1E in FIG. 3) based on the sampling clock control signal SR1D.

  Sampling clock signal SR1E is input to AD converter 11B and AD converter 11C.

  The AD converter 11B samples the recording signal SR02 based on the input sampling clock signal SR1E, performs AD conversion, and outputs it as recording signal data SR1B.

  The AD converter 11C samples the gain control signal SR03 based on the input sampling clock signal SR1E, performs AD conversion, and outputs the gain control signal data SR1C.

  The recording signal data SR1B and the gain control signal data SR1C are input to the control unit 11E. The control unit 11E outputs the recording signal data SR1B, the gain control signal data SR1C, and the sampling clock control signal SR1D to the recording unit 110 as the recording data SR04.

  The recorded data SR04 output to the recording unit 110 is recorded in the recording unit 110.

  The recording unit may be a known unit such as a hard disk, an optical disk, a magneto-optical disk, or various memory cards.

  The above is the signal recording operation.

  Next, the reproduction operation of the signal recorded in the recording unit 110 will be described.

  FIG. 4 shows a detailed block diagram of the playback unit 201.

  The reproduction unit 201 includes a reproduction control unit 211, and a DA conversion unit 21 including a DA conversion unit 212, a DA conversion unit 213, and a reproduction sampling clock generation unit 214 (described as a reproduction SCLK generation unit 214 in FIG. 4). ing.

  The reproduction control unit 211 reads the recording data SR04 recorded in the recording unit 110 as reproduction data SP01, separates the recording signal data SR1B, the gain control signal data SR1C, and the sampling clock control signal SR1D, and regenerates each of the reproduction signal data SP11. The reproduction gain control signal data SP12 and the reproduction sampling clock control signal SP13 (described as the reproduction SCLK control signal SP13 in FIG. 4) are output.

  The reproduction signal data SP11 is input to the DA converter 212.

  The reproduction gain control signal data SP12 is input to the DA conversion unit 213.

  The reproduction sampling clock control signal SP13 that is a reference signal is input to the reproduction sampling clock generation unit 214.

  The reproduction sampling clock generation unit 214 generates a reproduction sampling clock signal SP14 (described as a reproduction SCLK signal SP14 in FIG. 4) based on the reproduction sampling clock control signal SP13.

  The reproduced sampling clock signal SP14 is input to the DA converter 212 and the DA converter 213.

  The DA conversion unit 212 performs DA conversion of the reproduction signal data SP11 based on the input reproduction sampling clock signal SP14, and outputs it to the reproduction signal processing unit 202 as a reproduction IF signal SP02.

  The DA conversion unit 213 performs DA conversion of the reproduction gain control signal data SP12 based on the input reproduction sampling clock signal SP14, and outputs it to the reproduction signal processing unit 202 as a reproduction gain control signal SP03.

  FIG. 5 shows a detailed block diagram of the reproduction signal processing unit 202.

  The reproduction signal processing unit 202 includes a low-pass filter 215 (described as LPF 215 in FIG. 5), a reproduction level control unit 216, and a reproduction signal amplification unit 22 including a variable gain amplification unit 217, a frequency conversion unit 218, and a bandpass filter 219. (Represented as BPF 219 in FIG. 5), a level adjusting unit 21A, and a reproduction signal frequency converting unit 23 including a band pass filter 21B (denoted as BPF 21B in FIG. 5).

  The reproduction IF signal SP02 is input to the low-pass filter 215 and output as an IF signal SP15 from which unnecessary harmonics are removed.

  The IF signal SP15 is input to the variable gain amplifier 217.

  The reproduction gain control signal SP03 is input to the reproduction level control unit 216, necessary signal processing is performed, and is output as the reproduction gain control signal SP16.

  Based on the reproduction gain control signal SP16, the variable gain amplification unit 217 amplifies or attenuates the IF signal SP15 so as to be equal to the output level before the recording signal amplification unit 13 performs adjustment, and outputs it as the IF signal SP17. .

  The IF signal SP17 is input to the mixer 218B provided in the frequency conversion unit 218. The mixer 218B also receives a predetermined oscillation signal SP18 output from the local oscillator 218A included in the frequency converter 218, and the mixer 218B performs frequency conversion of the IF signal SP17 based on the oscillation signal SP18 (to a high frequency). Conversion) and output as an RF signal SP19.

  The RF signal SP19 is input to the bandpass filter 219, an unnecessary noise signal generated by frequency conversion is cut, and the band-limited RF signal SP1A is output.

  The RF signal SP1A is input to the level adjustment unit 21A, subjected to signal amplification so as to have a predetermined output level, and output as an RF signal SP1B.

  The RF signal SP1B is input to the band-pass filter 21B, unnecessary bands are cut, and the band-limited reproduction RF signal SP04 is output to the receiver under test 300.

  The above is the reproduction operation of the recorded signal.

  Through the above operation, when the broadcast signal is recorded after AD conversion, the output level of the received broadcast signal is detected and automatically adjusted so that the output level of the recorded broadcast signal does not exceed the dynamic range of AD conversion. When recording with the adjustment amount and playing back the recorded broadcast signal, the recorded broadcast signal and the adjustment amount are DA converted, and the output level of the broadcast signal is returned to the output level before the output level adjustment based on the adjustment amount. Thus, recording and reproduction of broadcast signals can be performed with high accuracy.

  As mentioned above, although the Example of this invention was explained in full detail with drawing, an Example is only an illustration of this invention and this invention is not limited only to the structure of an Example. Accordingly, it goes without saying that design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

  For example, the block diagrams are not limited to those shown in FIGS. 2 to 5, for example, the recording control unit 11 </ b> E and the reproduction control unit 211 are made one control unit.

1 is a schematic block diagram of a signal recording / reproducing apparatus in an embodiment of the present invention. It is a block diagram of the recorded signal processing part in the embodiment of the present invention. It is a block diagram of the recording part in embodiment of this invention. It is a block diagram of the reproducing part in embodiment of this invention. It is a block diagram of the reproduction | regeneration signal processing part in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Signal receiving part 12 Output level setting part 13 Recording signal amplification part 14 Recording signal frequency conversion part 15 AD conversion part 21 DA conversion part 22 Reproduction signal amplification part 23 Reproduction signal frequency conversion part 100 Signal recording part 101 Reception antenna 102 Recording signal processing Unit 103 recording unit 111, 116, 118, 219, 21B bandpass filter 112, 119 amplifier 113 output level detector 114 output level controller 115, 217 variable gain amplifier 117, 218 frequency converter 117A, 218A local oscillator 117B 218B Mixer 11B, 11C AD conversion unit 11D Sampling clock generation unit 11E Recording control unit 110 Recording unit 200 Signal reproduction unit 201 Reproduction unit 202 Reproduction signal processing unit 211 Reproduction control unit 212, 213 DA conversion unit 214 Reproduction sampling clock generation unit 1 1A, 215 Low-pass filter 216 Reproduction level control unit 21A Level adjustment unit 300 Receiver under test

Claims (4)

A signal recording / reproducing apparatus for performing AD conversion and recording of a radio frequency signal and DA converting and reproducing the recorded radio frequency signal,
When recording the radio frequency signal, the output level of the received radio frequency signal is detected, and the output level is adjusted so that the output level of the radio frequency signal to be recorded does not exceed the dynamic range of the AD conversion. And, the radio frequency signal whose output level is adjusted and the adjustment amount of the output level are AD-converted with a sampling clock signal generated based on a predetermined reference signal and recorded together with the reference signal,
When reproducing the recorded radio frequency signal, the recorded radio frequency signal and the adjustment amount are DA-converted based on the sampling clock signal generated based on the reference signal, and the radio frequency signal is converted based on the adjustment amount. A signal recording / playback apparatus, wherein the output level of a frequency signal is returned to the output level before the adjustment and played back. A signal receiving unit that receives a radio frequency signal, and an output level that detects an output level of the radio frequency signal received by the signal receiving unit, and calculates a gain when the radio frequency signal is amplified based on the output level A recording signal amplifying unit for amplifying the radio frequency signal based on the gain calculated by the output level setting unit; and a recording signal frequency for performing frequency conversion of the radio frequency signal amplified by the recording signal amplifying unit. A recording signal processing unit having a conversion unit;
An AD converter that AD converts the radio frequency signal frequency-converted by the recording signal frequency converter and the gain calculated by the output level setting unit with a sampling clock signal generated based on a predetermined reference signal; and the AD conversion A recording control unit that outputs the radio frequency signal, the gain, and the reference signal that are AD-converted by a unit as recording data;
A recording unit for recording the recording data output by the recording control unit;
A signal recording unit with
A reproduction control unit for reading the recorded data recorded in the recording unit and separating it into the radio frequency signal, the gain and the reference signal, and the radio frequency signal and the gain separated by the reproduction control unit as the reference signal A DA converter that performs DA conversion based on the sampling clock signal generated based on
A reproduction signal amplification unit that amplifies the radio frequency signal DA-converted by the DA conversion unit based on the gain DA-converted by the DA conversion unit, and the radio frequency signal amplified by the reproduction signal amplification unit A reproduction signal processing unit having a reproduction signal frequency conversion unit for performing frequency conversion;
A signal reproduction unit comprising:
A signal recording / reproducing apparatus comprising:   The output level setting unit sets the gain so that an output level of the radio frequency signal frequency-converted by the recording signal frequency conversion unit does not exceed a dynamic range of the AD conversion unit. The signal recording and playback device described in 1. The reproduction signal amplifying unit amplifies the radio frequency signal so that an output level of the radio frequency signal after amplification is equal to an input level of the radio frequency signal input to the recorded signal amplification unit. The signal recording / reproducing apparatus according to claim 3 or 4.

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