Code of Federal Regulations Title 47. Telecommunication § 47.90.214 Transient frequency behavior

Current as of January 02, 2025 | Updated by Findlaw Staff

Transmitters designed to operate in the 150–174 MHz and 421–512 MHz frequency bands must maintain transient frequencies within the maximum frequency difference limits during the time intervals indicated:

		All equipment
Time intervals^1,²	Maximum frequency difference³	150 to 174 MHz	421 to 512 MHz
Transient Frequency Behavior for Equipment Designed to Operate on 25 kHz Channels
t₁⁴	± 25.0 kHz	5.0 ms	10.0 ms
t₂	± 12.5 kHz	20.0 ms	25.0 ms
t₃⁴	± 25.0 kHz	5.0 ms	10.0 ms
Transient Frequency Behavior for Equipment Designed to Operate on 12.5 kHz Channels
t₁⁴	± 12.5 kHz	5.0 ms	10.0 ms
t₂	± 6.25 kHz	20.0 ms	25.0 ms
t₃⁴	± 12.5 kHz	5.0 ms	10.0 ms
Transient Frequency Behavior for Equipment Designed to Operate on 6.25 kHz Channels
t₁⁴	± 6.25 kHz	5.0 ms	10.0 ms
t₂	± 3.125 kHz	20.0 ms	25.0 ms
t₃⁴	± 6.25 kHz	5.0 ms	10.0 ms

¹ t_on is the instant when a 1 kHz test signal is completely suppressed, including any capture time due to phasing.

t ₁ is the time period immediately following t_on.

t ₂ is the time period immediately following t₁.

t ₃ is the time period from the instant when the transmitter is turned off until t_off.

t _off is the instant when the 1 kHz test signal starts to rise.

² During the time from the end of t₂ to the beginning of t₃, the frequency difference must not exceed the limits specified in § 90.213.

³ Difference between the actual transmitter frequency and the assigned transmitter frequency.

⁴ If the transmitter carrier output power rating is 6 watts or less, the frequency difference during this time period may exceed the maximum frequency difference for this time period.

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Cite this article: FindLaw.com - Code of Federal Regulations Title 47. Telecommunication § 47.90.214 Transient frequency behavior - last updated January 02, 2025 | https://codes.findlaw.com/cfr/title-47-telecommunication/cfr-sect-47-90-214/

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