DS90UB934-Q1: fdev and fmod

Shinji Tsuji

Genius 14139 points

Part Number: DS90UB934-Q1

Hi team,

fdev is specified as +/-0.5% to +/-2.5% at 25 to100MHz

fmod is specified as 5 to 50kHz at 25 to 100MHz.

Could you advise the fdev and fmod at PCLK = 74.25MHz?

SSCG_MOD_RATE register describes as frequency modulation PCLK/3168 +/-1%

74.25MHz/3168 = 23.4kHz +/-1%

Is this modulation frequency?

Or 23.4kHz is the modulation frequency and +/-1% is the deviation?

deviation frequency also changes by PCLK?

regards,

over 4 years ago

0 Jiashow Ho over 4 years ago

TI__Genius 11340 points

Hi Tsuji-san,

fdev is the actual frequency deviation, and fmod is the modulation frequency and describes how quickly the frequency deviates.

Regarding your question on SSCG, yes, 23.4kHz would be the modulation frequency and +/- 1% is the deviation. However, the datasheet has a spec that shows possible deviation from +/-1%.

Best,

Jiashow

0 Shinji Tsuji over 4 years ago in reply to Jiashow Ho

TI__Genius 14139 points

HI Jiashow,

Does it mean the deviation range at 74.25MHz is +/-1% = +/- 742.5kHz typical

and varies from +/-0.5%(371.25kHz) to +/-2.5% (1.856MHz) over PVT at 74.25MHz?

Or fdev range is also proportional to PCLK frequency?

regards,

0 Jiashow Ho over 4 years ago in reply to Shinji Tsuji

TI__Genius 11340 points

Hi Tsuji-san,

You're correct. The deviation range would be 74.25 between +/-0.5% and +/- 2.5%, with +/-1% being the nomimal value.

Best,

Jiashow

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DS90UB934-Q1: fdev and fmod