System on chip and display system

Abstract

A system-on-chip and a display system. The system-on-chip can include an on-screen display circuit, a memory control circuit, and an audio processor. The on-screen display circuit can be used to control an on-screen display of textual information. The memory control circuit can be coupled to a memory and can be used to read text-to-speech data corresponding to the textual information from the memory. The audio processor can be coupled to the memory control circuit and can include a text-to-speech circuit, where the text-to-speech circuit can be used to receive the text-to-speech data from the memory control circuit and generate an audio output based on at least the text-to-speech data.

Description

Technical Field

[0001] This invention relates to display systems, and more particularly to a system on a chip (SoC) for use in display systems, which integrates a text-to-speech circuit with text-to-speech function and an on-screen display circuit for controlling the display of text information on the screen into the same chip. Background Technology

[0002] In existing display systems, when text information is displayed on-screen (OSD) menus, if the display system also needs to play the corresponding audio through speakers or headphones, a system-on-a-chip (SoC) with text-to-speech (TOS) functionality needs to be coupled externally to the scaler SoC in the display system. This increases costs. Furthermore, the display system needs to control the TOS SoC via a user command interface, which may cause desynchronization between text display and audio playback, leading to certain side effects. Therefore, there is a strong need for a novel SoC that integrates both the TOS circuitry and the on-screen display circuitry for controlling the text information display on the screen into a single chip, thereby solving the aforementioned problems without introducing side effects or in a way that is unlikely to introduce side effects. Summary of the Invention

[0003] Therefore, one of the objectives of this invention is to provide a system-on-a-chip that integrates a text-to-speech circuit with text-to-speech function and an on-screen display circuit for controlling the display of text information on a screen into the same chip, as well as a related display system, to solve the above-mentioned problems.

[0004] According to an embodiment of the present invention, a system-on-a-chip (SoC) is provided. The SoC may include a screen display circuit, a memory control circuit, and an audio processor. The screen display circuit can be used to control the screen display of text information. The memory control circuit may be coupled to a memory and used to read text-to-speech data corresponding to the text information from the memory. The audio processor may be coupled to the memory control circuit and includes a text-to-speech circuit, wherein the text-to-speech circuit is used to: receive text-to-speech data from the memory control circuit; and generate an audio output based on at least the text-to-speech data.

[0005] According to an embodiment of the present invention, a display system is provided. The display system may include a memory and a system-on-a-chip (SoC), wherein the memory can be used to store text-to-speech data. The SoC may include an on-screen display circuit, a memory control circuit, and an audio processor. The on-screen display circuit can be used to control the on-screen display of text information. The memory control circuit is coupled to the memory and is used to read text-to-speech data corresponding to the text information from the memory. The audio processor is coupled to the memory control circuit and includes a text-to-speech circuit, wherein the text-to-speech circuit is used to: receive text-to-speech data from the memory control circuit; and generate an audio output based on at least the text-to-speech data.

[0006] One advantage of this invention is that, since the system-on-a-chip provided by this invention integrates a text-to-speech circuit with text-to-speech function and an on-screen display circuit for controlling the display of text information on the screen into the same chip, the asynchrony between text display and voice playback can be greatly improved. In addition, since the display system provided by this invention does not require an additional system-on-a-chip, but is coupled to the outside of the scaler system-on-a-chip in the display system to perform the text-to-speech function, the cost can be greatly reduced. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a display system according to an embodiment of the present invention.

[0008] Figure 2 This is a schematic diagram of an audio processor according to an embodiment of the present invention.

[0009] Figure 3 According to an embodiment of the present invention Figure 1 The control flowchart of the finite state machine is shown.

[0010] Figure 4 According to an embodiment of the present invention Figure 3 The diagram shown is an example of a control flow chart.

[0011] Figure 5 According to an embodiment of the present invention Figure 3 Another example of a control flow diagram is shown.

[0012] Symbol Explanation

[0013] 10: Display System

[0014] 100: Scaler System Single Chip

[0015] 102: Receiving circuit

[0016] 104: Video Processor

[0017] 106,20: Audio Processor

[0018] 107,200: Text-to-speech circuit

[0019] 108: Display circuit on the screen

[0020] 110: Finite State Machine

[0021] 112: Transmission circuit

[0022] 114: Memory control circuit

[0023] 120: Memory

[0024] 140: Monitor

[0025] 160, 220: Audio processing circuit

[0026] 180: Audio playback device

[0027] IN_S: Input signal

[0028] VI_S: Video signal

[0029] AU_S: Audio signal

[0030] TTS_CMD: Text-to-Speech command

[0031] CS: Control Commands

[0032] AU_OUT: Audio output

[0033] TTS_DATA: Text-to-speech data

[0034] P_AU_OUT: Processed audio output

[0035] TEXT: Text Information

[0036] 202: First-In-First-Out Circuit

[0037] 204: Upsampling processing circuit

[0038] 206, 208: Volume control circuit

[0039] 210: Synthetic Circuit

[0040] AD_AU_S: Adjusted audio signal

[0041] AD_TTS_DATA: Adjusted text-to-speech data

[0042] MIX_AU_S: Synthesized audio signal

[0043] 300, 400, 500: Audio preparation status

[0044] 302, 402, 502: Text-to-speech playback status

[0045] 304, 404, 504: Audio playback status Detailed Implementation

[0046] Figure 1 This is a schematic diagram of a display system 10 according to an embodiment of the present invention. Figure 1 As shown, the display system 10 may include a scaler system-on-a-chip (SoC) 100, a memory 120, a display 140, an audio processing circuit 160, and an audio playback device 180. The memory 120 may be a random access memory (RAM) or a sequential peripheral interface flash memory (SPI flash memory), but the invention is not limited to these. The scaler SoC 100 may include a receiving circuit 102, a video processor 104, an audio processor 106, an on-screen display (OSD) circuit 108, a finite-state machine (FSM) 110, a transmission circuit 112, and a memory control circuit 114. The receiving circuit 102 can be used to receive an input signal IN_S, wherein the input signal IN_S may include a video signal VI_S and an audio signal AU_S. For example, the input signal IN_S can be a displayport (DP) signal, a high definition multimedia interface (HDMI) signal, a video graphics array (VGA) signal, or an auxiliary input (AUX IN) signal, etc.

[0047] Video processor 104 is coupled to receiving circuit 102 and can be used to process video signal VI_S. When a text message TEXT needs to be displayed on display 140, video processor 104 can notify on-screen display circuit 108 to perform relevant processing. Video processor 104 in display system 10 is well known to those skilled in the art, and the operation of video processor 104 is not the focus of this disclosure. Therefore, this application's specification only describes the operation between audio processor 106, on-screen display circuit 108, and finite state machine 110. On-screen display circuit 108 is coupled to video processor 104 and display 140 and can be used to control the on-screen display of text message TEXT. Memory 120 can be used to store text-to-speech data TTS_DATA corresponding to text message TEXT. Note that, to save memory space, text-to-speech data TTS_DATA can be a mono audio signal. Memory control circuit 114 is coupled to memory 120 and can read text-to-speech data TTS_DATA from memory 120. The audio processor 106 can be coupled to the receiving circuit 102 and can be used to receive the audio signal AU_S. Furthermore, the audio processor 106 can also be coupled to the memory control circuit 120 and may include a text-to-speech (TTS) circuit 107 (for simplicity, ). Figure 1 The text-to-speech circuit 107 (labeled as "TTS circuit") is used to: receive text-to-speech data TTS_DATA from the memory control circuit 120; and generate an audio output AU_OUT based on at least the text-to-speech data TTS_DATA. A finite state machine 110 is coupled to the audio processor 106 and the on-screen display circuit 108, and can receive a text-to-speech command TTS_CMD from the on-screen display circuit 108, and transmit a control command CS to the audio processor 106 based on the text-to-speech command TTS_CMD to control the audio processor 106 (especially the text-to-speech circuit 107) to generate the audio output AU_OUT based on at least the text-to-speech data TTS_DATA.

[0048] For example, when the text-to-speech circuit 107 in the audio processor 106 receives text-to-speech data TTS_DATA from the memory control circuit 120 and the audio processor 106 does not receive an audio signal AU_S from the receiver circuit 102, the finite state machine 110 transmits a control command CS to the audio processor 106 based on the text-to-speech command TTS_CMD, so as to control the audio processor 106 (especially the text-to-speech circuit 107) to generate audio output AU_OUT based solely on the text-to-speech data TTS_DATA. As another example, when the audio processor 106 receives an audio signal AU_S from the receiver circuit 102 and the text-to-speech circuit 107 receives text-to-speech data TTS_DATA from the memory control circuit 120, the finite state machine 110 transmits a control command CS to the audio processor 106 based on the text-to-speech command TTS_CMD, so as to control the audio processor 106 (especially the text-to-speech circuit 107) to perform synthesis processing based on the audio signal AU_S and the text-to-speech data TTS_DATA to generate audio output AU_OUT.

[0049] The transmission circuit 112 can be coupled to the audio processor 106 and can be used to transmit the audio output AU_OUT to the audio processing circuit 160. The transmission circuit 112 can be an I2S (integrated interchip sound) transmission circuit, an S / PDIF (Sony / Philips Digital Interface Format) transmission circuit, or an auxiliary input interface transmission circuit, etc. The audio processing circuit 160 can be coupled to the transmission circuit 112 and can perform audio processing on the audio output AU_OUT transmitted by the transmission circuit 112 to generate a processed audio output P_AU_OUT. For example, the audio processing circuit 160 may include an audio codec and an audio amplifier system-on-a-chip (SoC), but the invention is not limited thereto. The audio playback device 180 can be coupled to the audio processing circuit 160 and can be used to play the processed audio output P_AU_OUT. For example, the audio playback device 180 can be a speaker or headphones, etc.

[0050] Figure 2 This is a schematic diagram of an audio processor 20 according to an embodiment of the present invention, wherein... Figure 1 The audio processor 106 shown can be used Figure 2 The audio processor 20 shown is used to implement this. Figure 2As shown, the audio processor 20 may include a text-to-speech circuit 200 and an audio processing circuit 220. The text-to-speech circuit 200 may include a first-in-first-out (FIFO) circuit 202, an upsampling circuit 204, multiple volume control circuits 206 and 208, and a synthesis circuit 210. The FIFO circuit 202 may be coupled to the memory control circuit 114 and may be used to receive text-to-speech data (TTS_DATA) from the memory control circuit 114. The upsampling processing circuit 204 can be coupled to the first-in-first-out circuit 202 and can be used to upsample the text-to-speech data TTS_DATA. For example, if the audio processor 20 receives the audio signal AU_S, the upsampling processing circuit 204 can be used to: upsample the text-to-speech data TTS_DATA so that the sampling rate of the text-to-speech data TTS_DATA is the same as the sampling rate of the audio signal AU_S; adjust the data size of the text-to-speech data TTS_DATA so that the bit depth of the text-to-speech data TTS_DATA is the same as the bit depth of the audio signal AU_S; and / or map the text-to-speech data TTS_DATA from a mono audio signal to a stereo audio signal. For example, if the audio processor 20 does not receive the audio signal AU_S, the upsampling processing circuit 204 can be used to: upsample the text-to-speech data TTS_DATA to increase the sampling frequency of the text-to-speech data TTS_DATA to a predetermined sampling frequency; adjust the data size of the text-to-speech data TTS_DATA to adjust the bit depth of the text-to-speech data TTS_DATA to a predetermined bit depth; and / or map the text-to-speech data TTS_DATA from a mono audio signal to a stereo audio signal.

[0051] Volume control circuit 206 can be coupled to upsampling processing circuit 204 and can be used to control the volume of text-to-speech data TTS_DATA to generate adjusted text-to-speech data AD_TTS_DATA. Volume control circuit 208 can be used to receive audio signal AU_S and can control the volume of audio signal AU_S to generate adjusted audio signal AD_AU_S. Synthesis circuit 210 can be coupled to volume control circuit 206 and volume control circuit 208, and can be used to synthesize the adjusted audio signal AD_AU_S and the adjusted text-to-speech data AD_TTS_DATA to generate a synthesized audio signal MIX_AU_S. For example, if audio processor 20 receives audio signal AU_S, synthesis circuit 210 can synthesize the adjusted audio signal AD_AU_S and the adjusted text-to-speech data AD_TTS_DATA to generate the synthesized audio signal MIX_AU_S (that is, audio output AU_OUT is generated based on synthesized audio signal MIX_AU_S). For another example, if audio processor 20 does not receive audio signal AU_S, synthesis circuit 210 directly transmits the adjusted text-to-speech data AD_TTS_DATA to audio processing circuit 220 (that is, audio output AU_OUT is generated based on adjusted text-to-speech data AD_TTS_DATA) for subsequent processing. The audio processing circuit 220 can be coupled to the synthesis circuit 210 and can perform audio processing on the synthesized audio signal MIX_AU_S (or the adjusted text-to-speech data AD_TTS_DATA) to generate audio output AU_OUT. For example, the audio processing circuit 220 may include a volume adjustment circuit (not shown) and the volume adjustment circuit can be used to control the volume of the synthesized audio signal MIX_AU_S (or the adjusted text-to-speech data AD_TTS_DATA) to generate audio output AU_OUT.

[0052] Figure 3 According to an embodiment of the present invention Figure 1 The control flowchart of the finite state machine 110 for the text-to-speech circuit 107 is shown below, in which... Figure 1 The audio processor 106 and text-to-speech circuit 107 shown can be respectively transmitted through... Figure 2 The audio processor 20 and text-to-speech circuit 200 shown are used to implement this. Finite state machine 110 can transmit control command CS to audio processor 106 based on the text-to-speech command TTS_CMD from the on-screen display circuit 108, to control audio processor 106 (especially text-to-speech circuit 107) to generate audio output AU_OUT based on at least text-to-speech data TTS_DATA. Figure 3As shown, the initial state of finite state machine 110 is audio preparing state 300, and the states of finite state machine 110 also include text-to-speech playback state (TTS playback state; for simplicity, ...). Figure 3 The states are marked as "TTS playback state" 302 and audio playback state 304. When the finite state machine 110 is in the audio preparation state 300, the finite state machine 110 waits for the text-to-speech circuit 107 to receive the audio signal AU_S or waits to receive the text-to-speech command TTS_CMD from the on-screen display circuit 108.

[0053] When finite state machine 110 is in audio preparation state 300, when finite state machine 110 receives a text-to-speech command TTS_CMD from the on-screen display circuit 108, finite state machine 110 transitions from audio preparation state 300 to text-to-speech playback state 302, and controls text-to-speech circuit 107 to generate audio output AU_OUT based solely on text-to-speech data TTS_DATA (especially adjusted text-to-speech data AD_TTS_DATA) via control command CS. After text-to-speech circuit 107 generates audio output AU_OUT (e.g., after audio playback device 180 finishes playing processed audio output P_AU_OUT), finite state machine 110 transitions back from text-to-speech playback state 302 to audio preparation state 300.

[0054] When the finite state machine 110 is in the audio preparation state 300, when the text-to-speech circuit 107 receives the audio signal AU_S, the finite state machine 110 transitions from the audio preparation state 300 to the audio playback state 304 to control the playback of the audio signal AU_S, and controls the text-to-speech circuit 107 to generate the audio output AU_OUT based solely on the audio signal AU_S (especially the adjusted audio signal AD_AU_S) through the control command CS. After the text-to-speech circuit 107 no longer receives the audio signal AU_S, the finite state machine 110 transitions from the audio playback state 304 back to the audio preparation state 300.

[0055] When the finite state machine 110 is in the audio playback state 304, when the finite state machine 110 receives the text-to-speech command TTS_CMD from the display circuit 108 on the screen, the finite state machine transitions from the audio playback state 304 to the text-to-speech playback state 302. It then controls the text-to-speech circuit 107 to perform synthesis processing based on the audio signal AU_S and the text-to-speech data AU_OUT (that is, to synthesize the adjusted audio signal AD_AU_S and the adjusted text-to-speech data AD_TTS_DATA to generate the synthesized audio signal MIX_AU_S) through the control command CS. The audio output AU_OUT is then generated based on the synthesized audio signal MIX_AU_S. After the text-to-speech circuit 107 generates the audio output AU_OUT (for example, after the audio playback device 180 finishes playing the processed audio output P_AU_OUT), the finite state machine 110 transitions from the text-to-speech playback state 302 back to the audio playback state 304 to continue playing the audio signal AU_S.

[0056] Figure 4 According to an embodiment of the present invention Figure 3 The example shown is a control flow diagram, in which Figure 1 The audio processor 106 and text-to-speech circuit 107 shown can be respectively transmitted through... Figure 2The audio processor 20 and text-to-speech circuit 200 shown are used to implement this. In this embodiment, the audio processor 20 does not receive the audio signal AU_S, and the upsampling processing circuit 204 sets the predetermined sampling frequency and predetermined bit depth to 48 kHz and 24 bits, respectively. Furthermore, for this example, the state transitions of the finite state machine 110 can be represented by dashed lines. When it is necessary to control the display of the text information TEXT on the screen, the screen display circuit 108 transmits the text-to-speech command TTS_CMD to the audio processor 20, and the finite state machine 110 transitions from the audio preparation state 400 to the text-to-speech playback state 402 to perform playback processing of the text-to-speech data TTS_DATA. The memory control circuit 114 can be used to read the text-to-speech data TTS_DATA corresponding to the text information TEXT from the memory 120. The text-to-speech circuit 200 receives the text data from the memory control circuit 114. After the text-to-speech data TTS_DATA is converted to speech data, the upsampling processing circuit 204 can be used to: upsample the text-to-speech data TTS_DATA to increase the sampling frequency of the text-to-speech data TTS_DATA to a predetermined sampling frequency (i.e., 48 kHz); adjust the data size of the text-to-speech data TTS_DATA to adjust the bit depth of the text-to-speech data TTS_DATA to a predetermined bit depth (i.e., 24 bits); and map the text-to-speech data TTS_DATA from a mono audio signal to a stereo audio signal.

[0057] Next, the volume control circuit 206 can control the volume of the text-to-speech data TTS_DATA to generate adjusted text-to-speech data AD_TTS_DATA. For example, the volume control circuit 206 can be used to set the volume setting of playing the text-to-speech data TTS_DATA from 0% to 80%. Even though the audio processor 20 does not receive the audio signal AU_S, the volume control circuit 208 can still be used to maintain the volume setting of playing the audio signal AU_S at a predetermined volume (e.g., 0%). Synthesis circuit 210 can be used to directly transmit the adjusted text-to-speech data AD_TTS_DATA to audio processing circuit 220 (i.e., the audio output AU_OUT is generated based on the adjusted text-to-speech data AD_TTS_DATA) for subsequent processing. Audio processing circuit 220 can perform audio processing on the adjusted text-to-speech data AD_TTS_DATA to generate audio output AU_OUT. After text-to-speech circuit 200 generates audio output AU_OUT (e.g., after audio playback device 180 finishes playing the processed audio output P_AU_OUT), finite state machine 110 transitions from text-to-speech playback state 402 back to audio preparation state 400. In addition, volume control circuit 206 can be used to set the volume setting of playing text-to-speech data TTS_DATA from 80% back to 0%, and volume control circuit 208 can be used to maintain the volume setting of playing audio signal AU_S at the predetermined volume (e.g., 0%). For the sake of brevity, a similar description of this embodiment will not be repeated in detail here.

[0058] Figure 5 According to an embodiment of the present invention Figure 3 Another example of a control flow diagram is shown, in which Figure 1 The audio processor 106 and text-to-speech circuit 107 shown can be respectively transmitted through... Figure 2The audio processor 20 and text-to-speech circuit 200 shown are used to implement this. In this embodiment, the audio processor 20 receives an audio signal AU_S, and the sampling frequency and bit depth of the audio signal AU_S are 96 kHz and 24 bits, respectively, where the audio signal AU_S is a display port audio signal. Furthermore, for this example, the state transitions of the finite state machine 110 can be represented by dashed lines. Initially, the finite state machine 110 is in the audio playback state 504. When the finite state machine 110 receives the text-to-speech command TTS_CMD from the display circuit 108 on the screen, the finite state machine transitions from the audio playback state 504 to the text-to-speech playback state 502, and controls the text-to-speech circuit 200 to perform synthesis processing based on the audio signal AU_S and the text-to-speech data TTS_DATA through the control command CS. The memory control circuit 114 can be used to read the text-to-speech data TTS_DATA corresponding to the text information TEXT from the memory 120. The text-to-speech circuit 200 receives the text-to-speech data TTS_DATA from the memory control circuit 114. After ATA, the upsampling processing circuit 204 can be used to: upsample the text-to-speech data TTS_DATA so that the sampling frequency of the text-to-speech data TTS_DATA is the same as the sampling frequency of the audio signal AU_S (i.e., the sampling frequency of TTS_DATA is equal to 96 kHz); adjust the data size of the text-to-speech data TTS_DATA so that the bit depth of the text-to-speech data TTS_DATA is the same as the bit depth of the audio signal AU_S (i.e., the bit depth of the text-to-speech data TTS_DATA is equal to 24 bits); and map the text-to-speech data TTS_DATA from a mono audio signal to a stereo audio signal.

[0059] Next, the volume control circuit 206 can control the volume of the text-to-speech data TTS_DATA to generate adjusted text-to-speech data AD_TTS_DATA, and the volume control circuit 208 can control the volume of the audio signal AU_S to generate adjusted audio signal AD_AU_S. For example, the volume control circuit 206 can be used to set the volume setting of playing the text-to-speech data TTS_DATA from 0% to 80%, and the volume control circuit 208 can be used to set the volume setting of playing the audio signal AU_S from a predetermined volume to 20%. Synthesis circuit 210 can be used to synthesize the adjusted audio signal AD_AU_S and the adjusted text-to-speech data AD_TTS_DATA to generate a synthesized audio signal MIX_AU_S. Audio processing circuit 220 can perform audio processing on the synthesized audio signal MIX_AU_S to generate an audio output AU_OUT. After the text-to-speech circuit 200 generates the audio output AU_OUT (e.g., after the audio playback device 180 finishes playing the processed audio output P_AU_OUT), finite state machine 110 can transition from text-to-speech playback state 502 back to audio playback state 504 to continue playing the audio signal from the display port. In addition, volume control circuit 206 can be used to set the volume setting of the text-to-speech data TTS_DATA from 80% back to 0%, and volume control circuit 208 can be used to set the volume setting of the audio signal AU_S from 20% back to a predetermined volume. For the sake of brevity, a similar description of this embodiment will not be repeated in detail here.

[0060] In summary, since the system-on-a-chip provided by this invention integrates a text-to-speech circuit with text-to-speech function and an on-screen display circuit for controlling the display of text information on the screen into the same chip, the asynchrony between text display and voice playback can be greatly improved. In addition, since the display system provided by this invention does not require an additional system-on-a-chip, but is coupled externally to the scaler system-on-a-chip in the display system to perform the text-to-speech function, the cost can be greatly reduced.

[0061] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. A system-on-a-chip (SoC) comprising: A screen display circuit used to control the display of text information on the screen; A memory control circuit, coupled to a memory, is used to read text-to-speech data corresponding to the text information from the memory; An audio processor, coupled to the memory control circuit, includes a text-to-speech circuit, wherein the text-to-speech circuit is used to: The text-to-speech data is received from the memory control circuit. as well as Generate an audio output based on at least the text-to-speech data; A finite state machine is coupled to the display circuitry on the screen and the audio processor, and is used to receive a text-to-speech command from the display circuitry on the screen, and to control the audio processor to generate the audio output based on at least the text-to-speech data according to the text-to-speech command. The finite state machine has an initial state of audio preparation. When the finite state machine is in the audio preparation state, it waits for the text-to-speech circuit to receive an audio signal or waits to receive the text-to-speech command from the on-screen display circuit. When the text-to-speech circuit receives the audio signal, the state of the finite state machine transitions from the audio preparation state to an audio playback state to control the playback of the audio signal. When the finite state machine is in the audio playback state and receives the text-to-speech command from the display circuit on the screen, the state of the finite state machine transitions from the audio playback state to a text-to-speech playback state, and the finite state machine controls the text-to-speech circuit to perform synthesis processing based on the audio signal and the text-to-speech data to generate the audio output. After the text-to-speech circuit generates the audio output, the state of the finite state machine transitions from the text-to-speech playback state back to the audio playback state.

2. The system-on-a-chip as claimed in claim 1, wherein the text-to-speech circuit is further configured to control the volume of the text-to-speech data to generate adjusted text-to-speech data, and the audio output is generated based on the adjusted text-to-speech data.

3. The system-on-a-chip as described in claim 1, wherein the text-to-speech circuit is further configured to: Receive an audio signal; The volume of the audio signal and the text-to-speech data are controlled separately to generate an adjusted audio signal and an adjusted text-to-speech data. as well as The adjusted audio signal and the adjusted text-to-speech data are synthesized to produce a synthesized audio signal. The audio output is generated based on the synthesized audio signal.

4. The system-on-a-chip as described in claim 3, wherein the text-to-speech circuit comprises: An upsampling processing circuit is used to upsample the text-to-speech data so that the sampling frequency of the text-to-speech data is the same as the sampling frequency of the audio signal.

5. The system-on-a-chip as described in claim 3, wherein the text-to-speech circuit comprises: An upsampling processing circuit is used to adjust the data size of the text-to-speech data so that the bit depth of the text-to-speech data is the same as the bit depth of the audio signal.

6. The system-on-a-chip as claimed in claim 1, wherein the text-to-speech data is a mono audio signal, and the text-to-speech circuit comprises: The sampling processing circuit is used to: The text-to-speech data is upsampled so that a sampling frequency of the text-to-speech data is the same as a predetermined sampling frequency. The data size of the text-to-speech data is adjusted so that the bit depth of the text-to-speech data is the same as a predetermined bit depth; and The text-to-speech data is mapped from the mono audio signal to a stereo audio signal.

7. The system-on-a-chip as claimed in claim 1, wherein when the finite state machine receives the text-to-speech command from the on-screen display circuit, the finite state machine transitions from the audio preparation state to a text-to-speech playback state, and controls the text-to-speech circuit to generate the audio output based on the text-to-speech data; and after the text-to-speech circuit generates the audio output, the finite state machine transitions from the text-to-speech playback state back to the audio preparation state.

8. A display system comprising: A memory for storing text-to-speech data; and A single-chip system includes: A screen display circuit used to control the display of text information on the screen; A memory control circuit is coupled to the memory and is used to read the text-to-speech data from the memory, wherein the text-to-speech data corresponds to the text information; as well as An audio processor, coupled to the memory control circuit, includes a text-to-speech circuit, wherein the text-to-speech circuit is used to: The text-to-speech data is received from the memory control circuit. as well as Generate an audio output based on at least the text-to-speech data; as well as A finite state machine is coupled to the display circuitry on the screen and the audio processor, and is used to receive a text-to-speech command from the display circuitry on the screen, and to control the audio processor to generate the audio output based on at least the text-to-speech data according to the text-to-speech command. The finite state machine has an initial state of audio preparation. When the finite state machine is in the audio preparation state, it waits for the text-to-speech circuit to receive an audio signal or waits to receive the text-to-speech command from the on-screen display circuit. When the text-to-speech circuit receives the audio signal, the state of the finite state machine transitions from the audio preparation state to an audio playback state to control the playback of the audio signal. When the finite state machine is in the audio playback state and receives the text-to-speech command from the display circuit on the screen, the state of the finite state machine transitions from the audio playback state to a text-to-speech playback state, and the finite state machine controls the text-to-speech circuit to perform synthesis processing based on the audio signal and the text-to-speech data to generate the audio output. After the text-to-speech circuit generates the audio output, the state of the finite state machine transitions from the text-to-speech playback state back to the audio playback state.

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