The present application claims priority to Chinese Patent Application No. 202011399587.X, titled “METHOD AND SYSTEM FOR AUTOMATICALLY ADJUSTING INTENSITY OF SIGNAL OUTPUTTED BY HDMI TRANSMITTER”, filed on Dec. 2, 2020 with the China National Intellectual Property Administration, which is incorporated herein by reference in its entirety.

FIELD

The present disclosure relates to the technical field of signal transmission, and in particular to a method and a system for automatically adjusting an intensity of a signal outputted by a high definition multimedia interface (HDMI) transmitter.

BACKGROUND

An HDMI is a common video signal interface, and may be applied in devices such as a set-top box, a digital versatile disc (DVD) player, a personal computer, a game console, a digital audio and a television.

When an HDMI transmitter transmits a signal to an HDMI receiver via an HDMI transmission line, the signal is increasingly damaged as a frequency of the signal increases during transmission. In order for the HDMI receiver to receive the signal with a better waveform, it is required to compensate for the damaged signal. In the pre-emphasis technology, a high-frequency component in the signal is enhanced at the beginning of the transmission line to compensate for excessive attenuation of the high-frequency component during the transmission. However, the current pre-emphasis processing adopts a fixed pre-emphasis intensity. Energy is wasted in case of a short HDMI transmission line, and insufficient compensation for high-frequency energy results in poor quality of a signal received by the HDMI receiver in case of a long HDMI transmission line.

SUMMARY

In view of this, a method and a system for automatically adjusting intensity of a signal outputted by an HDMI transmitter are provided according to the present disclosure, to optimally adjust the intensity of the signal for different HDMI transmission line lengths and different signal frequencies, so as to acquire best quality of an outputted signal.

The following technical solutions are provided according to the present disclosure.

A method for automatically adjusting intensity of a signal outputted by an HDMI transmitter is provided according to a first aspect of the present disclosure. The method includes: determining a length of an HDMI transmission line between the HDMI transmitter and an HDMI receiver; determining a swing amplitude and a pre-emphasis intensity of the signal outputted by the HDMI transmitter based on the length of the HDMI transmission line and a frequency of the signal outputted by the HDMI transmitter; and configuring an HDMI output drive circuit based on the swing amplitude and the pre-emphasis intensity.

In an embodiment, the determining a length of an HDMI transmission line between the HDMI transmitter and an HDMI receiver includes: determining whether the HDMI receiver is in a connection state, and transmitting a detection pulse signal to the HDMI receiver via an interface of the HDMI transmitter and starting timing when the detection pulse signal is transmitted in a case that the HDMI receiver is in a connection state; and receiving a pulse signal reflected by the HDMI receiver via a detection port of the HDMI transmitter, and stopping the timing when the reflected pulse signal is received. A timing result indicates the length of the HDMI transmission line.

In an embodiment, the detection port is one of a hot plug detection (HPD) port, a display data channel (DDC) port, and a consumer electronics control (CEC) port.

In an embodiment, the detection pulse signal is a negative pulse signal.

A system for automatically adjusting intensity of a signal outputted by an HDMI transmitter is provided according to a second aspect of the present disclosure. The system includes a detection module, a microcontroller unit (MCU) and an HDMI output drive circuit. The detection module is configured to determine a length of an HDMI transmission line between the HDMI transmitter and an HDMI receiver. The MCU is configured to determine a swing amplitude and a pre-emphasis intensity of the signal outputted by the HDMI transmitter based on the length of the HDMI transmission line and a frequency of the signal outputted by the HDMI transmitter. The MCU is further configured to configure the HDMI output drive circuit based on the swing amplitude and the pre-emphasis intensity.

In an embodiment, the detection module includes an HPD port, a detection pulse generation circuit, a detection port, a counter controller and a counter. The HPD port is configured to: determine whether the HDMI receiver is in a connection state; and transmit a signal to the MCU, where the signal indicates whether the HDMI receiver is in a connection state. The detection pulse generation circuit is configured to, when a detection start signal transmitted by the MCU is received, generate a pulse signal and transmit the pulse signal to the detection port. The detection port is configured to output a detection pulse signal to a channel of the HDMI transmission line corresponding to the detection port in response to the pulse signal transmitted by the detection pulse generation circuit, and transmit a first trigger signal to the counter controller. The counter controller is configured to control the counter to start timing when the first trigger signal is received. The counter is configured to record the number of cycles of a clock signal during the timing. The detection port is further configured to receive a pulse signal reflected by the HDMI receiver, and transmit a second trigger signal to the counter controller when the reflected pulse signal is received. The counter controller is further configured to, when the second trigger signal is received, control the counter to stop timing, and transmit a detection completion signal to the MCU. The MCU is further configured to read a timing result of the counter when the detection completion signal is received. The timing result indicates the length of the HDMI transmission line.

In an embodiment, the detection port is one of an HPD port, a DDC port, and a CEC port.

In an embodiment, each of the detection pulse signal, the first trigger signal, the second trigger signal, and the pulse signal generated by the detection pulse generation circuit is a negative pulse signal.

Compared with the conventional technology, technical solutions of the present disclosure have the following beneficial effects.

A method and a system for automatically adjusting intensity of a signal outputted by an HDMI transmitter are provided according to the present disclosure. With the method, a correspondence among the length of the HDMI transmission line, the frequency of the signal outputted by the HDMI transmitter, and the swing amplitude of the signal outputted by the HDMI transmitter is preset, and a correspondence among the length of the HDMI transmission line, the frequency of the signal outputted by the HDMI transmitter, and the pre-emphasis intensity of the signal outputted by the HDMI transmitter is preset, such that the swing amplitude and the pre-emphasis intensity of the signal outputted by the HDMI transmitter can be determined based on the length of the HDMI transmission line and the frequency of the signal outputted by the HDMI transmitter in an actual communication system, thereby configuring the HDMI output drive circuit. Therefore, a swing amplitude and a pre-emphasis intensity of a signal outputted by the HDMI transmitter can vary with a length of an HDMI transmission line and a frequency of the signal, to compensate for attenuation of the signal due to the transmission line, such that an HDMI receiver can receive a signal with optimum quality.

