CN110753255A

CN110753255A - Transmission stream receiving device and clock frequency setting method thereof

Info

Publication number: CN110753255A
Application number: CN201810815720.1A
Authority: CN
Inventors: 宋新爱; 叶执政
Original assignee: Ali Corp
Current assignee: Ali Corp
Priority date: 2018-07-24
Filing date: 2018-07-24
Publication date: 2020-02-04
Anticipated expiration: 2038-07-24
Also published as: CN110753255B

Abstract

A transmission stream receiving device and a clock frequency setting method thereof. The transmission stream receiving device comprises a demodulator, a controller and a conditional access device. The demodulator receives an external signal and converts the external signal into serial data. The controller is coupled to the demodulator. The conditional access device is coupled to the controller. The controller sets the demodulator to transmit the stream data to the conditional access device according to the clock frequency, and detects a maximum allowable clock frequency that can be used and allowed by the conditional access device.

Description

Transmission stream receiving device and clock frequency setting method thereof

[ technical field ] A method for producing a semiconductor device

The present invention relates to a transmission stream technology, and more particularly, to a transmission stream receiving apparatus and a clock frequency setting method thereof.

[ background of the invention ]

A Digital Video Broadcasting (DVB) is a device that receives an external signal source and displays an image from the external signal source on a display screen. In response to the development of technology, some digital set-top boxes may be additionally equipped with a Conditional Access Module (CAM) to view pay digital tv content ordered by the user. Some digital television systems also have corresponding interfaces to allow users to install additional conditional access modules.

In the process of watching specific paid digital images or television contents, a general interface on the television or a digital set top box needs to be provided with a corresponding conditional access module so that the played contents can be decrypted/decoded normally and played on a display screen. When the external signal source encodes the digital video using a video modulation technique such as digital video broadcasting satellite second generation (DVB-S2) Adaptive Coded Modulation (ACM)/Variable Coded Modulation (VCM), the clock frequency corresponding to each frame in the transmission stream will be changed due to different operation modes. Although the set-top box or the digital television system can calculate the clock frequency of the transmission stream by using the demodulator and adjust the demodulator thereof, the conditional access module installed in the set-top box or the digital television system only has limited one or more clock frequencies due to the relationship of hardware or design, so that the conditional access module may not support the corresponding clock frequency. Therefore, how to coordinate the clock frequency between the set-top box or the digital television system and the conditional access module becomes one of the important issues in this field.

[ summary of the invention ]

The invention provides a transmission stream receiving device and a clock frequency setting method thereof, which can accurately obtain the highest allowable clock frequency used by a conditional access device so as to be compatible with various conditional access devices and obtain the best digital image presentation effect.

The invention discloses a transmission stream receiving device. The transmission stream receiving device comprises a demodulator, a controller and a conditional access device. The demodulator receives an external signal and converts the external signal into serial data. The controller is coupled to the demodulator. The conditional access device is coupled to the controller. The controller sets the demodulator to transmit the stream data to the conditional access device according to the clock frequency, and detects a maximum allowable clock frequency that can be used and allowed by the conditional access device.

The invention discloses a clock frequency setting method of a transmission stream receiving device. The transmission stream receiving device comprises a demodulator and a conditional access device. The clock frequency setting method comprises the following steps. The demodulator is configured to transmit the stream data to the conditional access apparatus according to the clock frequency. And detecting the highest allowable clock frequency that the conditional access apparatus can use and can tolerate.

Based on the above, the transmission stream receiving device and the clock frequency setting method thereof according to the embodiments of the present invention provide the to-be-tested stream data corresponding to different clock frequencies to the conditional access device when the transmission stream receiving device and the conditional access device are connected to each other, and determine whether the stream data processed by the conditional access device is normally output. Therefore, the transmission stream receiving device can detect the highest clock frequency which can be used and allowed by the conditional access device according to the method, so that the subsequent demodulation/decoding operation of the transmission stream is smoother. In addition, the transmission stream receiving device of the embodiment can be compatible with various types of conditional access devices, and can obtain the best image decoding effect under the hardware limitation of the conditional access devices.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

[ description of the drawings ]

Fig. 1 is a block diagram of a transmission stream receiving apparatus according to an embodiment of the invention.

Fig. 2 is a flowchart illustrating a clock frequency setting method of a transmission stream receiving apparatus according to an embodiment of the invention.

Fig. 3 is a detailed flowchart of a clock frequency setting method according to an embodiment of the invention.

Fig. 4 is a detailed flowchart of a clock frequency setting method according to another embodiment of the invention.

Fig. 5 is a flowchart illustrating a clock frequency setting method of a transmission stream receiving apparatus according to another embodiment of the invention.

[ notation ] to show

100: transmission series flow receiving device

110: demodulator

120: conditional access apparatus

130: stream decoder

140: controller

200. 500: method of producing a composite material

S210, S220, S310-S360, S440-S460, S510-S530: step (ii) of

ES: external signal

TS: streaming data

[ detailed description ] embodiments

Fig. 1 is a block diagram of a ts receiving apparatus 100 according to an embodiment of the invention. The apparatus 100 can be installed in a set-top box or a digital television system. Referring to fig. 1, the apparatus 100 for receiving a transport stream of the present embodiment mainly includes a demodulator 110, a conditional access apparatus 120 and a controller 140. The transmission stream receiving device 100 may also include a stream decoder 130.

The demodulator 110 is for example an ADSL modem, a cable modem and a fiber modem or other similar devices or combinations of the above. The demodulator 110 receives an external signal ES from a signal source (e.g., a satellite antenna or a cable), and converts the external signal ES into a stream data TS to output the stream data TS to the conditional access apparatus 120. In detail, the demodulator 110 may include a Transmission Stream Output (TSO) module. When the external signal ES employs a video modulation technique such as digital video broadcasting satellite second generation (DVB-S2) Adaptive Coding Modulation (ACM)/Variable Coding Modulation (VCM), the transport stream output module may determine a transport rate (bitrate) for outputting the streaming data TS according to the relevant parameters and internal settings of the external signal ES. And sets the clock frequency of the transmission stream output module according to the transmission code rate, so that the demodulator 110 demodulates the external signal ES according to the set clock frequency to obtain the stream data TS, and transmits the stream data TS to the conditional access apparatus 120. The demodulator 110 may also include other modules for generating data streams, but is not limited thereto.

The Conditional Access device 120 (or CAM) of the present embodiment is a card-type device, and a user can purchase the Conditional Access device 120 from a specific vendor and electrically connect to the transport stream receiving device 100 through a Common Interface (CI), so that the user can view additional digital image content. Examples of the Universal Interface include, but are not limited to, Universal Serial Bus (USB), firewire, ethernet, Universal Asynchronous Receiver/Transmitter (UART), Serial Peripheral Interface (SPI), and the like. The stream decoder 130 is, for example, a binary decoder, a binary-decimal decoder, a display decoder, or other similar devices or combinations of devices capable of decoding a stream. The stream decoder 130 receives the streamed data output from the conditional access device 120, decompresses the compressed streamed data, and presents the video content to the user.

The controller 140 includes, for example, a Central Processing Unit (CPU), or other Programmable general purpose or special purpose Microprocessor (Microprocessor), Digital Signal Processor (DSP), Programmable controller, Application Specific Integrated Circuit (ASIC), Programmable Logic Device (PLD), or other similar Device or combination of devices. Further, the controller 140 may also include a memory. The controller 140 is coupled to the demodulator 110 and the conditional access device 120. The controller 140 of the present embodiment is connected to the conditional access apparatus 120 via a general-purpose interface.

In order to view the extra digital video content, the conditional access apparatus 120 obtains the stream data TS through the demodulator 110 and performs a specific type of decryption/decoding on the stream data TS, so that the decoded stream data can be decompressed by the stream decoder 130 to obtain a digital video for normal playing. If the conditional access apparatus 120 is not available, the additional digital video contents cannot be played normally because they are not decrypted/decoded. Therefore, the conditional access apparatus 120 still needs to know the clock frequency corresponding to the stream data TS when performing decryption/decoding.

Since some of the current image modulation techniques (e.g., Adaptive Code Modulation (ACM)/Variable Code Modulation (VCM)) allow the clock frequency to vary based on different situations, the demodulator 110 can configure a higher clock frequency and have a larger redundancy for various clock frequency variations, so that the demodulation/decoding operation can be performed normally. However, the conditional access device 120 may only support a specific number of clock frequencies or a specific range of clock frequencies due to hardware or design concerns. Therefore, when the conditional access apparatus 120 cannot support some clock frequencies adjusted or set by the demodulator 110, an error will occur in the decryption/decoding process of the conditional access apparatus 120, and the stream decoder 130 cannot output digital images for normal playing.

Therefore, the embodiment of the invention uses the controller 140 to configure the demodulator 110 such that the demodulator 110 transmits the corresponding streaming data TS to the conditional access device 120 according to the preset clock frequency, and thereby detects the maximum allowable clock frequency that can be used and allowed by the conditional access device 120. In this way, the controller 140 can control the modem 110 to perform demodulation/decoding operations mainly using the highest allowable clock frequency supported by the conditional access apparatus 120, so that the transmission stream processed by the conditional access apparatus 120 can be normally outputted and played. The operation of each element and the related step flow are described in detail by the following embodiments.

Fig. 2 is a flowchart illustrating a clock frequency setting method 200 of a transmission stream receiving apparatus according to an embodiment of the invention. Referring to fig. 1 and fig. 2, the clock frequency setting method 200 of the present embodiment is applied to the transmission stream receiving apparatus 100 of fig. 1. The timing of the clock frequency setting method 200 can be adjusted according to the requirement of the user. For example, one implementation is that when the dsrx apparatus 100 is booted and the controller 140 detects that the dsr 120 is coupled to the dsr, the clock frequency setting method 200 can be performed to detect the highest allowable clock frequency that the dsr 120 can use and the dsr 120 can tolerate. Alternatively, the clock frequency setting method 200 may be performed by the controller 140 when the ts receiver 100 is running and the conditional access apparatus 120 is connected to the controller 140 of the ts receiver 100 by using the universal interface. Furthermore, when the ts rx 100 needs to utilize the conditional access apparatus 120 to decrypt/decode the encrypted/locked stream data, the controller 140 can perform the clock frequency setting method 200 at this time.

In step S210, the controller 140 configures the demodulator 110 such that the demodulator 110 transmits the corresponding streaming data TS to the conditional access device 120 according to one or more predetermined clock frequencies. In detail, the controller 140 configures the demodulator 110 such that the demodulator 110 transmits the test data corresponding to the predetermined clock frequency to the conditional access device 120. Also, the controller 140 controls the conditional access apparatus 120 to convert the test data into streaming data to be tested. Then, the controller 140 adjusts the predetermined clock frequency according to whether the stream data to be tested can be normally output through the stream decoder 130 or not, until the test data corresponding to the predetermined clock frequency can be normally output through the conditional access apparatus 120 and the stream decoder 130.

In step S220, the controller 140 utilizes the above step S210 to detect the highest allowable clock frequency that can be used and allowed by the conditional access device 120. In detail, the controller 140 sets the predetermined clock frequency corresponding to the streaming data to be tested that can be normally output as the highest allowable clock frequency that can be allowed by the conditional access apparatus 120. Therefore, the demodulator 110 and the conditional access apparatus 120 can normally demodulate/decrypt/decode the serial data TS contained in the external signal ES according to the maximum allowable clock frequency, and the stream decoder 130 can decompress the serial data processed by the conditional access apparatus 120 to normally present the digital image to the user.

The controller 140 can implement the clock frequency setting method in various ways, which will be described in the following with different embodiments and subsequent figures (e.g., fig. 3 and 4). Fig. 3 is a detailed flowchart of a clock frequency setting method according to an embodiment of the invention. The embodiment of FIG. 3 illustrates the controller 140 gradually increasing the default clock frequency to determine whether the highest allowable clock frequency that the conditional access device 120 can use and can tolerate is detected. Steps S310 to S350 in fig. 3 may correspond to step S210 in fig. 2; step S360 in fig. 3 may correspond to step S220 in fig. 2. Referring to fig. 1 and 3, the controller 140 transmits the test data corresponding to the predetermined clock frequency to the conditional access device 120 (step S310). Next, the controller 140 controls the conditional access apparatus 120 to convert the test data into streaming data to be tested (step S320). Then, the controller 140 determines whether the streaming data to be tested can be normally output (step S330). The "whether the streaming data to be tested can be normally outputted" is to compare the original data corresponding to the test data and the streaming data processed by the streaming decoder 130 with each other in a binary manner or in a comparison manner by calculating the result with an algorithm, so as to know whether the two data are the same. If the comparison result is the same, then it is determined that the stream data to be tested can be normally output; if the comparison result is different, it is determined that the stream data to be tested cannot be outputted normally. In addition, the controller 140 can also compare the encoded original data corresponding to the test data with the encoded streaming data that is output by the conditional access device 120 but not decoded by the streaming decoder 130, so as to know whether the encoded original data and the encoded streaming data are the same, and further determine whether the streaming data to be tested can be normally output.

It should be noted that, in other embodiments, it may also be determined whether the streaming data to be tested can be normally output by other internal modules or external devices connected to the ts receiving apparatus 100, instead of the controller 140 only performing the above determination.

If the determination in step S330 is yes, it means that the streaming data to be tested can be normally output. If the determination in step S330 is the first determination and the determination is yes, since the controller 140 cannot know whether the preset clock frequency corresponding to the current streaming data to be tested is the highest allowable clock frequency of the conditional access apparatus 120, the controller 140 gradually increases the preset clock frequency (step S340), and retransmits the test data according to the increased preset clock frequency (step S350). After step S350, the process returns to step S320, and the controller 140 controls the conditional access apparatus 120 to convert the test data into the streaming data to be tested, and determines whether the streaming data to be tested can be normally output again (step S330) until the controller 140 determines that the streaming data to be tested cannot be normally output (i.e., the process proceeds from step S330 to step S360).

If the determination in step S330 is "no", which indicates that the streaming data to be tested corresponding to the predetermined clock frequency cannot be normally output, the controller 140 sets the predetermined clock frequency corresponding to the streaming data to be tested that can be normally output last time to the maximum allowable clock frequency (step S360). That is, the controller 140 sets the predetermined clock frequency of the streaming data to be tested that can be normally outputted through the conditional access apparatus 120 at the previous time as the highest allowable clock frequency that can be allowed by the conditional access apparatus 120.

Fig. 4 is a detailed flowchart of a clock frequency setting method according to another embodiment of the invention. The embodiment of FIG. 4 illustrates the controller 140 gradually ramping down the default clock frequency to determine whether the highest allowable clock frequency that the conditional access device 120 can use and tolerate is detected. Steps S310, S320, S330, S440 and S450 in fig. 4 may correspond to step S210 in fig. 2; step S460 in fig. 4 may correspond to step S220 in fig. 2. Referring to fig. 1 and 4, steps S310 to S330 in fig. 4 are the same as steps S310 to S330 in fig. 3. The difference between the two is that steps S440, S450 and S460 of fig. 4 are different from steps S340, S350 and S360 of fig. 3, and steps S440, S450 and S460 are further described below.

If the determination in step S330 is negative, it means that the streaming data to be tested cannot be output normally. If the step S330 is the first determination and the determination is no, the controller 140 can only know that the preset clock frequency at this time is not the clock frequency supported by the conditional access apparatus 120. Therefore, the controller 140 gradually decreases the predetermined clock frequency (step S440), and retransmits the test data according to the decreased predetermined clock frequency (step S450). After step S450, the process returns to step S320, and the controller 140 controls the conditional access apparatus 120 to convert the test data into the streaming data to be tested, and determines whether the streaming data to be tested can be normally output again (step S330) until the controller 140 determines that the streaming data to be tested can be normally output (i.e., the process proceeds from step S330 to step S460).

If the determination in step S330 is yes, which indicates that the to-be-tested serial data can be normally output, the controller 140 sets the preset clock frequency corresponding to the to-be-tested serial data that can be normally output this time as the maximum allowable clock frequency (step S460). That is, the controller 140 sets the preset clock frequency of the streaming data to be tested that can be normally output through the conditional access apparatus 120 this time to the highest allowable clock frequency that can be allowed by the conditional access apparatus 120.

It should be noted that the maximum allowable clock frequency in the embodiments of the present invention refers to the highest value of all clock frequencies that enable normal data output, which are detected by the ts receiving apparatus and the clock frequency setting method of the present invention. Therefore, in the step of gradually increasing/decreasing the frequency, the frequency interval of each frequency increase/decrease will affect the detected maximum allowable clock frequency. For example, assume that the maximum allowable clock frequency of the conditional access apparatus is 11.6MHz and the default clock frequency is 8MHz, i.e. the controller is turned up from 8 MHz. If the frequency interval is gradually increased by 1MHz each time, the frequency is increased from 8MHz to 12MHz (for example, gradually increased to 9MHz, 10MHz, 11MHz, and 12MHz) through 4 frequency-adjusting steps, and then the serial data to be measured cannot be normally output because 12MHz exceeds 11.6 MHz. Therefore, the present embodiment selects the frequency (i.e., 11MHz) that can be normally outputted last time as the maximum allowable clock frequency. Therefore, the maximum allowable clock frequency detected finally is 11MHz, and the total number of the required frequency-up steps is 4; if the frequency is gradually increased from 8MHz at a frequency interval of 0.5MHz each time, the maximum allowable clock frequency detected finally is 11.5MHz (for example, the maximum allowable clock frequency is gradually increased to 8.5MHz, 9MHz, 9.5MHz, 10MHz, 10.5MHz, 11MHz, 11.5MHz, and 12MHz), and the total number of the required frequency-increasing steps is 8, and the frequency-increasing step is not terminated until 12MHz exceeds 11.6MHz and the serial data to be measured cannot be normally output. Therefore, in the step of gradually increasing/decreasing the frequency, the smaller the frequency interval is, the higher the accuracy of the detected maximum allowable clock frequency is, but the total number of steps required for detection is relatively increased. However, the user can use the present invention according to the actual requirement, and the present invention is not limited thereto.

The controller 140 of the present embodiment can store the maximum allowable clock frequency corresponding to each conditional access device 120 in addition to detecting and obtaining the maximum allowable clock frequency of the conditional access device 120. Therefore, when the user is replacing a different conditional access device 120, the controller 140 does not need to detect the corresponding highest allowable clock frequency again, so that the ts receiving device 100 is more easily compatible with different types of conditional access devices 120. Fig. 5 and the corresponding exemplary embodiment are described here.

Fig. 5 is a flowchart illustrating a clock frequency setting method 500 of a transmission stream receiving apparatus according to another embodiment of the invention. Referring to fig. 1 and 5, it is assumed that the controller 140 in the ts rx 100 detects the maximum allowed clock frequency for a plurality of different dscs 120, and the controller 140 stores the maximum allowed clock frequency and the identification code corresponding to the dscs 120 in a corresponding table or database, and corresponds the stored identification code corresponding to the dscs 120 to the maximum allowed clock frequency.

The controller 140 detects whether the conditional access device 120 is connected to the controller 140 of the ts sink 100 through the universal interface (step S510). If the step S510 is yes, the controller 140 determines whether the identifier corresponding to the currently connected conditional access apparatus 120 is one of the stored identifiers (step S520). If yes in step S520, the controller 140 sets the demodulator 110 using the stored clock frequency corresponding to one of the stored identification codes (step S530). That is, the demodulator 110 performs the processing of the external signal ES using the clock frequency corresponding to the current conditional access apparatus 120 that has been detected last time. The identification code corresponding to the conditional access device 120 is, for example, one of a device name, a device model, a built-in identification code of a manufacturer, a media access control address (MAC), or a combination thereof.

If the step S510 is no, which means that the conditional access apparatus 120 and the controller 140 are not connected through the universal interface, the step S510 may be continuously repeated. If the step S520 is no, which means that the identification code corresponding to the current conditional access apparatus 120 is not one of the stored identification codes, the controller 140 continues to perform the steps S210 and S220 to detect the highest allowable clock frequency that can be used and allowed by the conditional access apparatus 120. Please refer to the flowchart of fig. 2 and the descriptions of the above embodiments for step S210 and step S220.

In summary, the transmission stream receiving apparatus and the clock frequency setting method thereof according to the embodiments of the invention provide the to-be-tested stream data corresponding to different clock frequencies to the conditional access apparatus when the transmission stream receiving apparatus and the conditional access apparatus are connected to each other, and determine whether the stream data processed by the conditional access apparatus is normally output. Therefore, the transmission stream receiving device can detect the highest clock frequency which can be used and allowed by the conditional access device according to the method, so that the subsequent demodulation/decoding operation of the transmission stream is smoother. In addition, the transmission stream receiving device of the embodiment can be compatible with various types of conditional access devices, and can obtain the best image decoding effect under the hardware condition of the conditional access devices.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. A transmission stream receiving apparatus, comprising:

a demodulator for receiving an external signal and converting the external signal into serial data;

a controller coupled to the demodulator; and

a conditional access apparatus coupled to the controller,

the controller sets the demodulator to transmit the streaming data to the conditional access device according to a clock frequency, and detects a highest allowable clock frequency that can be used and allowed by the conditional access device.

2. The apparatus of claim 1, wherein the controller transmits test data corresponding to a predetermined clock frequency to the conditional access apparatus, controls the conditional access apparatus to convert the test data into streaming data to be tested, and adjusts the predetermined clock frequency according to whether the streaming data to be tested is normally output, so as to obtain the maximum allowable clock frequency that the conditional access apparatus can tolerate.

3. The transmission stream receiving apparatus according to claim 2, wherein when the streaming data to be tested can be normally output, the controller increases the predetermined clock frequency, retransmits the test data according to the increased predetermined clock frequency, controls the conditional access apparatus to convert the test data into the streaming data to be tested, and determines whether the streaming data to be tested is normally output again until the streaming data to be tested cannot be normally output,

and the controller sets the preset clock frequency corresponding to the streaming data to be tested which can be normally output in the previous time as the highest allowable clock frequency.

4. The transmission stream receiving apparatus according to claim 2, wherein the controller decreases the predetermined clock frequency when the streaming data under test cannot be normally output, controls the conditional access apparatus to convert the test data into the streaming data under test according to the decreased predetermined clock frequency to retransmit the test data, and determines whether the streaming data under test is normally output again until the streaming data under test can be normally output,

and the controller sets the preset clock frequency corresponding to the current to-be-detected serial data which can be normally output at this time as the highest allowable clock frequency.

5. The transmission stream receiving device according to claim 1, wherein the controller is connected to the conditional access apparatus through a common interface,

wherein the controller stores the clock frequency and an identification code corresponding to the conditional access apparatus, and corresponds the identification code corresponding to the conditional access apparatus and having been stored to the clock frequency, and,

when the current conditional access device is connected to the controller through the universal interface, the controller determines whether the identification code corresponding to the current conditional access device is one of the stored identification codes,

if the current identification code corresponding to the conditional access device is one of the stored identification codes, the controller uses the stored clock frequency corresponding to the one of the stored identification codes to set the demodulator.

6. The transmission stream receiving device according to claim 1, wherein the controller is connected to the conditional access apparatus through a common interface,

upon connecting the controller to the conditional access apparatus through the generic interface, the controller detects the highest allowable clock frequency that the conditional access apparatus is capable of using and that the conditional access apparatus is capable of allowing.

7. The transmit stream receiver apparatus of claim 1, wherein the controller detects the highest allowable clock frequency that the conditional access apparatus can use and the conditional access apparatus can tolerate when the transmit stream receiver apparatus performs a power-on initialization and the controller and the conditional access apparatus are coupled to each other.

8. A clock frequency setting method of a transmission stream receiving device, wherein the transmission stream receiving device comprises a demodulator and a conditional access device, the clock frequency setting method comprises:

setting the demodulator to transmit serial data to the conditional access device according to a clock frequency; and

the highest allowable clock frequency that the conditional access apparatus can use and can tolerate is detected.

9. The clock frequency setting method of claim 8, wherein setting the demodulator to transmit streamed data to the conditional access apparatus according to the clock frequency comprises:

transmitting test data corresponding to a preset clock frequency to the conditional access device;

controlling the conditional access apparatus to convert the test data into streaming data to be tested; and

adjusting the preset clock frequency according to whether the streaming data to be detected is normally output,

and, detecting a highest allowable clock frequency that the conditional access apparatus can use and can tolerate includes:

and setting the preset clock frequency corresponding to the normally output streaming data to be detected as the highest allowable clock frequency.

10. The method of claim 9, wherein adjusting the predetermined clock frequency according to whether the streaming data to be tested is normally output comprises:

when the streaming data to be detected can be normally output, increasing the preset clock frequency;

retransmitting the test data according to the increased preset clock frequency, controlling the conditional access device to convert the test data into streaming data to be tested, and judging whether the streaming data to be tested is normally output again until the streaming data to be tested cannot be normally output; and

and setting the preset clock frequency corresponding to the streaming data to be tested which can be normally output in the previous time as the highest allowable clock frequency.

11. The method of claim 9, wherein adjusting the predetermined clock frequency according to whether the streaming data to be tested is normally output comprises:

when the streaming data to be detected cannot be normally output, reducing the preset clock frequency;

retransmitting the test data according to the reduced preset clock frequency, controlling the conditional access device to convert the test data into streaming data to be tested, and judging whether the streaming data to be tested is normally output again until the streaming data to be tested can be normally output; and

and setting the preset clock frequency corresponding to the current to-be-detected serial data which can be normally output at this time as the highest allowable clock frequency.

12. The clock frequency setting method of claim 8, wherein the controller of the TS receiver is connected to the conditional access apparatus through a common interface,

the clock frequency setting method further includes:

storing the identification code corresponding to the highest allowable clock frequency and the conditional access device, and corresponding the identification code which corresponds to the conditional access device and is stored to the clock frequency;

when the current conditional access device is connected to the transmission stream receiving device through the universal interface, judging whether an identification code corresponding to the current conditional access device is one of the stored identification codes or not; and

if the identification code corresponding to the current conditional access device is one of the stored identification codes, the stored clock frequency corresponding to the one of the stored identification codes is used for setting the demodulator.

13. The clock frequency setting method of claim 8, wherein the controller of the TS receiver is connected to the conditional access apparatus through a common interface,

14. The method of claim 8, wherein the controller detects the highest allowable clock frequency that the conditional access apparatus can use and the conditional access apparatus can tolerate when the ts rx apparatus performs power-on initialization and the controller of the ts rx apparatus and the conditional access apparatus are coupled to each other.