TDC1000: EXT Clock

user5837998

Part Number: TDC1000

Hello,

I am using the TDC1000-TDC2700EVM and want to use a external function generator, to ensure i can excite my ultrasonic transducers at a variety of different frequencies.

The setup was as following:

- the external function generator was connected to the input on the board designated for external clock (sine wave @ 1.6MHz, U(peak to peak) = 5V)

- JP6 jumper was moved to the EXT position

- On setup page of GUI set:

TDC_CLK_SOURCE_SEL to EXT_CLK

CLKFREQ(1-16MHz) to 1.600000- for 1.6MHz as source input.

- On TDC1000 tab

set the divider to 8 (1.6MHz/8 = 200kHz)

- Turned on the continuous trigger mode and couldnt see anything on my scope, probing the TX path.

Any suggestions on what could be wrong at my setup?

Thanks in advance and best regards.

over 6 years ago

0 Bharat Aravamudhan over 6 years ago

TI__Genius 11015 points

Hello,

We have received your question & will respond by tomorrow.

0 Bharat Aravamudhan over 6 years ago

TI__Genius 11015 points

Hello,

Please let me know the resonant frequency of the transducer that your are using.

Incase you are using a transducer with a resonant frequency 1Mhz, then you could setup the external clock to 2Mhz and the divider to 2 and match the external clock to the resonant freq of the transducer.

The idea of the frequency divider is to match the ext clock with the resonant frequency of the transducer in use.

0 user5837998 over 6 years ago in reply to Bharat Aravamudhan

Prodigy 40 points

Hi,

The resonance frequency is 200kHz.

To achieve this frequency at the Output i set the my function generator to 1.6MHz and the ext_clk frequency in the GUI to 1.6MHz as well.

The divider was set to 8.

0 Bharat Aravamudhan over 6 years ago in reply to user5837998

TI__Genius 11015 points

Hello,

Please send me plot of the Tx & Rx signal from the transducer. Have you tried to read the signals at the various test points in the EVM. Also is your transducer that is attached to the EVM have a transmit frequency of 200Khz. I see your setup as mentioned by you to be fine and it should work.

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TDC1000: EXT Clock